阅读说明：本技术 一种用于肺癌早期筛查和诊断的联合检测血清标志物、试剂盒及检测方法 (Combined detection serum marker, kit and detection method for early screening and diagnosis of lung cancer ) 是由 张建营 代丽萍 史健翔 王鹏 王晓 叶华 蒋迪 于 2019-09-18 设计创作，主要内容包括：本发明涉及一种用于肺癌早期筛查和诊断的联合检测血清标志物、包含该联合检测血清标志物的试剂盒以及检测方法,属于生物医学技术领域。本发明基于癌症驱动基因在肿瘤发生和发展中所起的作用,定制138个癌症驱动基因编码的154个人源重组蛋白和本实验室提供的26种人源重组蛋白的蛋白质芯片,共包含180个人源重组蛋白质,通过蛋白质芯片初步筛选出肺癌的早期检测血清标志物,再经过ELISA实验进行验证,最终筛选出可用于肺癌早期筛查和诊断的一组肺癌联合检测血清标志物,其包括TP53、NPM1、GNA11、JAK2、TSC1和PIK3CA共6种基因编码的蛋白,可辅助肺癌的临床诊断,具有灵敏度高、特异性强、成本低等优点。(the invention relates to a combined detection serum marker for early screening and diagnosis of lung cancer, a kit containing the combined detection serum marker and a detection method, and belongs to the technical field of biomedicine. Based on the functions of the cancer driver genes in tumorigenesis and development, the invention customizes 154 human-derived recombinant proteins coded by 138 cancer driver genes and a protein chip of 26 human-derived recombinant proteins provided by the laboratory, totally comprises 180 human-derived recombinant proteins, preliminarily screens out early detection serum markers of lung cancer through the protein chip, verifies through an ELISA experiment, and finally screens out a group of lung cancer combined detection serum markers which can be used for early screening and diagnosis of lung cancer, wherein the lung cancer combined detection serum markers comprise 6 gene coded proteins including TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA, can assist clinical diagnosis of lung cancer, and has the advantages of high sensitivity, strong specificity, low cost and the like.)

1. A combined detection serum marker for early screening and diagnosis of lung cancer, characterized in that: the combined detection serum marker comprises proteins coded by TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA genes;

The protein coded by the TP53 gene has an amino acid sequence shown in SEQ ID NO. 1;

The protein coded by the NPM1 gene has an amino acid sequence shown as SEQ ID NO. 3;

The protein coded by the GNA11 gene has an amino acid sequence shown as SEQ ID NO. 5;

The protein coded by the JAK2 gene has an amino acid sequence shown in SEQ ID NO. 10;

The protein coded by the TSC1 gene has an amino acid sequence shown as SEQ ID NO. 11;

The protein coded by the PIK3CA gene has an amino acid sequence shown in SEQ ID NO. 12.

2. The combined detection serum marker for early screening and diagnosis of lung cancer according to claim 1, characterized in that: the combined detection serum marker consists of proteins coded by 6 genes including TP53, NPM1, GNA11, JAK2, TSC1 and PIK3 CA.

3. A kit for early screening and diagnosis of lung cancer, characterized by: a combined test serum marker for early screening and diagnosis of lung cancer comprising any one of claims 1-2.

4. The kit for early screening and diagnosis of lung cancer according to claim 3, wherein: the combined detection serum marker is coated on a solid phase carrier.

5. The kit for early screening and diagnosis of lung cancer according to claim 4, wherein: the solid phase carrier is made of any one of polyvinyl chloride, polystyrene, polyacrylamide and cellulose.

6. The kit for early screening and diagnosis of lung cancer according to any one of claims 3-5, wherein: the kit also comprises any one or the combination of more of positive control serum, negative control serum, confining liquid, sample diluent, a second antibody, second antibody diluent, washing liquid, developing liquid and stopping liquid.

7. An assay method for the combined detection of serum markers for the early screening and diagnosis of lung cancer using any one of claims 1-2, characterized in that: the method comprises the following steps:

1) Respectively coating the combined detection serum markers, sealing and cleaning;

2) Performing primary antibody incubation and cleaning with the serum to be detected, performing secondary antibody incubation and cleaning;

3) Stopping the reaction after the color development of the color development system, and measuring the absorbance value;

4) By OD₄₅₀-OD₆₂₀The relative OD value is obtained, then a blank control is deducted, and the absorbance value of each index (namely the serum marker) is substituted into the following formula to calculate the value of the prediction probability P;

P＝1/(1+Exp(-(-9.161+42.136×OD_TP53-12.510×OD_NPM1+15.889×OD_GNA11+17.433×OD_JAK2+34.955×OD_TSC1-56.240×OD_PIK3CA)))；

OD in the formula_TP53、OD_NPM1、OD_GNA11、OD_JAK2、OD_TSC1、OD_PIK3CARespectively subtracting the absorbance value of the blank control from the relative OD value of each index;

When the P value is more than or equal to 0.5, preliminarily judging as a suspected lung cancer sample;

And when the P value is less than 0.5, the sample is preliminarily judged to be a normal sample.

Technical Field

The invention belongs to the technical field of biomedicine, and particularly relates to a combined detection serum marker for early screening and diagnosis of lung cancer, a kit containing the combined detection serum marker and a detection method. .

background

lung cancer is the first malignancy of morbidity and mortality in china and worldwide. During the last 40 years, the 5-year survival rate of lung cancer has only risen from 12% to 16%, the most important reason being that the diagnosis is already advanced, and in contrast, the postoperative survival rate of early-diagnosed lung cancer can be improved to 80%. Therefore, the early detection and early diagnosis have important clinical significance for the treatment and prognosis of the lung cancer. The detection means widely used at present comprise non-invasive examination (such as X-ray, CT, molybdenum target film and the like) and invasive examination (such as fiber bronchoscope, bronchography, B-ultrasound or CT positioning biopsy and the like), but lack compliance and possibility of popularization and application. The search for new lung cancer molecular markers, especially serum molecular markers, enables lung cancer patients to be effectively and timely early checked, diagnosed and treated, and is a key scientific problem for improving the survival rate and reducing the death rate of the lung cancer patients. Although some tumor markers, such as CA125 (cancer antigen 125), CA19-9 (cancer antigen 19-9), CEA (carcinoembryonic antigen), etc., can be used for the auxiliary detection of lung cancer at present, the sensitivity and specificity are not high, so that no ideal marker for the clinical early screening and diagnosis of lung cancer exists so far.

In recent years, in the field of human oncology, many studies have found that the sera of cancer patients contain a unique set of cellular proteins that induce autoantibody responses, called tumor-associated antigens (TAAs), and the antibodies that they induce are called anti-TAA antibodies (autoantibodies). The proposal of the concept guides a new direction for the research of early diagnosis of lung cancer. Autoantibodies to tumor-associated antigens (TAAs) are absent or have low titers in the serum of normal human and non-tumor patients, and the level of autoantibodies in the serum of patients often increases earlier than the appearance of tumor symptoms. Furthermore, anti-TAA antibodies have the advantage that other tumor markers, on the one hand, are capable of sustained and stable presence in serum, while other markers, including TAA itself, are rapidly degraded after its release by tumor cells or cleared by the body shortly after it enters the blood circulation. Moreover, the popularity of methods and reagents for detecting autoantibodies has also contributed to the study of the production pattern and function of anti-TAA antibodies in cancer patients. Therefore, the detection of autoantibodies to anti-TAAs can be used as serum markers for early tumor-assisted screening and diagnosis. At present, various national scholars have carried out related multiple researches, and the research result of EarlyCDT-Lung test is worth mentioning. EarlyCDT-Lungtest is the first tool for detecting lung cancer by detecting autoantibodies in serum, and is used for assisting physical examination methods of physicians, thereby improving the diagnosis rate of lung cancer. Initially, the assay included the detection of six TAAs autoantibodies (p53, NY-ESO-1, CAGE, GBU4-5, Annexin I and SOX2) with a sensitivity and specificity of 40% and 82% for lung cancer, respectively. The new EarlyCDT-Lung test updates TAAs autoantibodies to 7 (p53, NY-ESO-1, CAGE, GBU4-5, SOX2, HuD and MAGE A4), and the sensitivity and specificity are also improved to 47% and 90%, respectively. More than half (57%) of the patients with non-small cell Lung cancer with positive detection results of the autoantibodies are early-stage Lung cancer in stage I and stage II, and the early CDT-Lung test can be used as a biological marker detection tool for assisting CT in early-stage Lung cancer detection. These research results suggest that the detection of tumor-associated antigen antibodies will be expected to become an important serological biomarker for early detection of lung cancer. However, it is worth noting that EarlyCDT-Lung test has high specificity and positive predictive value, but the sensitivity is still not ideal (less than 50%), and many missed cases lead to a large number of patients not being discovered in time and the good chance of surgical treatment is missed. Given the current inadequacy of autoantibody detection in clinical applications for lung cancer diagnosis, the continued discovery and identification of new lung cancer-associated TAAs is still an important task.

subsequent studies over a decade have attempted to find more sensitive and specific anti-TAA autoantibodies for lung cancer diagnosis, optimizing the combination for lung cancer diagnosis. There are two common methods for finding valuable TAA autoantibodies: the first is serological screening of recombinant cDNA expression library (serological analysis of recombinant cDNA expression libraries, SEREX); the other is proteomics technology. In contrast to SEREX, proteomics technology enables screening of multiple tumor sera and enables screening of TAAs with post-translational modifications. During the development of tumors, hundreds of thousands of mutations of genes are involved, but only some key genes, called cancer driver genes, are mutated to cause the development of tumors. Studies suggest that different types of tumorigenesis generally contain 2-8 driver genes, and that mutations in these genes lead to preferential tumor growth, and that these genes can be divided into 12 signaling pathways by regulating the cell cycle, cell survival and genome to maintain 3 cell core processes. 138 cancer driver genes (see Vogelstein B. science. (2013)339(6127):1546-1558), including 74 cancer suppressor genes and 64 cancer genes, are currently found in a variety of tumor whole genome sequencing studies. The protein coded based on the cancer driving gene can also induce the body to generate corresponding autoantibodies in circulating blood of the body, and the research on the protein coded by the cancer driving gene and the autoantibodies in serum induced by the protein can reveal the occurrence, development or prognosis of tumors to a certain extent.

Disclosure of Invention

The invention aims to provide a combined detection serum marker for early screening and diagnosis of lung cancer, which is used for assisting clinical diagnosis of lung cancer.

Meanwhile, the invention also provides a kit containing the combined detection serum marker.

Finally, the invention provides a detection method which has high sensitivity, strong specificity and low cost and can assist the clinical diagnosis of the lung cancer.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

A combined detection serum marker for early screening and diagnosis of lung cancer comprises proteins coded by TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA genes.

Further, the combined detection serum marker consists of proteins coded by 6 genes including TP53, NPM1, GNA11, JAK2, TSC1 and PIK3 CA.

The protein coded by the TP53 gene has an amino acid sequence shown in SEQ ID NO. 1.

the protein coded by the NPM1 gene has an amino acid sequence shown as SEQ ID NO. 3.

The protein coded by the GNA11 gene has an amino acid sequence shown in SEQ ID NO. 5.

the protein coded by the JAK2 gene has an amino acid sequence shown in SEQ ID NO. 10.

The protein coded by the TSC1 gene has an amino acid sequence shown in SEQ ID NO. 11.

The protein coded by the PIK3CA gene has an amino acid sequence shown in SEQ ID NO. 12.

A kit for early screening and diagnosis of lung cancer comprises the combined detection serum marker. Specifically, the protein encoded by TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA genes.

Further, the combined detection serum marker consists of proteins coded by 6 genes including TP53, NPM1, GNA11, JAK2, TSC1 and PIK3 CA.

furthermore, the combined detection serum marker is coated on a solid phase carrier.

The solid phase carrier is made of polyvinyl chloride, polystyrene, polyacrylamide, cellulose and the like.

The solid phase carrier exists in the form of concave hole plate, test tube, spherulite, etc.

Further, the kit also comprises any one or combination of more of positive control serum, negative control serum, confining liquid, sample diluent, a second antibody, second antibody diluent, washing liquid, developing liquid and stopping liquid. The above-mentioned reagents can be selected as required in practical use.

1) Respectively coating the combined detection serum markers, sealing and cleaning;

2) Performing primary antibody incubation and cleaning with the serum to be detected, performing secondary antibody incubation and cleaning;

3) Stopping the reaction after the color development of the color development system, and measuring the absorbance value;

4) By OD₄₅₀-OD₆₂₀The relative OD value is obtained, then a blank control is deducted, and the absorbance value of each index (namely the serum marker) is substituted into the following formula to calculate the value of the prediction probability P;

P＝1/(1+Exp(-(-9.161+42.136×OD_TP53-12.510×OD_NPM1+15.889×OD_GNA11+17.433×OD_JAK2+34.955×OD_TSC1-56.240×OD_PIK3CA)))；

OD in the formula_TP53、OD_NPM1、OD_GNA11、OD_JAK2、OD_TSC1、OD_PIK3CARespectively subtracting the absorbance value of the blank control from the relative OD value of each index;

when the P value is more than or equal to 0.5, preliminarily judging as a suspected lung cancer sample;

And when the P value is less than 0.5, the sample is preliminarily judged to be a normal sample.

The secondary antibody used in the secondary antibody incubation was HRP-labeled mouse anti-human IgG.

The invention has the beneficial effects that:

The invention is based on the role of cancer driver genes in tumorigenesis and development, and prepares a human protein chip coded by 138 cancer driver genes, which comprises 180 human-derived recombinant proteins in total and is used for screening potential markers which can be used for diagnosing or otherwise characterizing cancers. According to the invention, early detection serum markers of lung cancer are preliminarily screened through a protein chip, and are verified through an ELISA (enzyme-linked immunosorbent assay) experiment, and a group of lung cancer combined detection serum markers which can be used for early screening and diagnosis of lung cancer is finally screened, wherein the lung cancer combined detection serum markers comprise 6 gene-coded proteins including TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA, so that the lung cancer combined detection serum markers can assist clinical diagnosis of lung cancer and have a better reference value.

The kit containing the 6 serum protein markers can be used for early screening and diagnosis of lung cancer, and the detection method has the characteristics of high sensitivity, strong specificity, low cost and the like, is simple and quick to operate, and can provide a basis for early diagnosis of lung cancer.

Drawings

FIG. 1 is a schematic diagram of the detection of a focused array-based human protein chip in an experimental example;

FIG. 2 is ROC curve analysis chart of 12 TAAs individually diagnosed from the protein chip in the experimental example;

FIG. 3 is a scattergram of SNR values of 12 TAAs selected by the protein chip in the experimental example;

FIG. 4 is a schematic diagram of indirect ELISA detection in an experimental example;

FIG. 5 is a ROC curve analysis chart of ELISA for verifying 12 TAAs for lung cancer alone in experimental examples;

FIG. 6 is a graph showing the distribution of OD value scatter of 12 TAAs verified by ELISA in the experimental examples;

FIG. 7 is a ROC plot of the data in the training set for ELISA-verified 6 TAAs combined diagnosis of lung cancer in the experimental examples;

FIG. 8 is a ROC plot of the data in the validation set for the ELISA validation of 6 TAAs for combined diagnosis of lung cancer in the experimental examples.

Detailed Description

The following examples are intended to illustrate the invention in further detail, but are not to be construed as limiting the invention in any way. The equipment and reagents used in the following examples and experimental examples were obtained commercially, except where otherwise specified.

Examples of the experiments

1 preparation of serum samples

1.1 serum samples for protein chip experiments

Primary lung cancer patients (lung cancer pathologically diagnosed) were collected at the first subsidiary hospital of the university of zheng and youan, beijing, with patient consent and approval by institutional review board and hospital ethics committee. All samples are collected by a red blood collection tube for 5-10mL of whole blood of a research object, after the samples are placed for 2 hours at room temperature, 1000g of the whole blood is centrifuged for 15 minutes, supernatant is taken, each sample is divided into a plurality of parts, labels are attached to the parts, and the parts are stored in a low-temperature refrigerator at minus 80 ℃ to avoid repeated freezing and thawing.

According to epidemiological analysis, 100 primary lung cancer sera and 50 of the healthy control sera of the Yogan hospital for the contemporaneous physical examination were finally collected for primary chip screening. Among 100 patients with primary lung cancer, 66 (66%) men and 34 (34%) women have a mean age of 61 ± 11 years and an age range of 26-85 years; in 50 cases of normal serum, there were 23 (46.0%) cases of males and 27 (54.0%) cases of females, with the mean age of 40. + -. 13 and the age range of 20-71 years. All sera from lung cancer patients were collected at a time when the patient was initially diagnosed with lung cancer and had not received any radiotherapy, chemotherapy, or surgical treatment. The normal human serum is from the physical examination population participating in the annual health physical examination and free of any malignant tumor symptoms.

1.2 serum samples for ELISA Experimental validation

(1) Serum samples were collected from the Beijing Youran Hospital and the first subsidiary Hospital of Zhengzhou university (see section 1.1 above for details).

(2) From the clinical laboratory of the first subsidiary hospital of Zhengzhou university (155 cases of primary lung cancer) and the cardiovascular survey program of Jinshui district of Zhengzhou City (155 cases of normal persons), there were 116 cases (74.84%) of male patients with primary lung cancer, 39 cases (25.16%) of female patients with an average age of 61 ± 10 years and an age range of 30-83 years; in 155 cases, 116 cases (74.84%) of males and 39 cases (25.16%) of females were selected from normal serum, and the average age was 60. + -.11 and the age range was 28-81 years. All sera from lung cancer patients were collected at a time when the patient was initially diagnosed with lung cancer and had not received any radiotherapy, chemotherapy, or surgical treatment.

2 protein chip customization for screening lung cancer diagnosis marker

Proteins (180 total human recombinant proteins) encoded by 138 cancer driver genes (see Vogelstein B. science. (2013)339(6127):1546-1558) were immobilized on protein chips for screening of tumor markers. The protein chip for screening tumor markers was a HuProtTM human protein chip custom-made by Biotech, Inc. of Bo Chong, Guangzhou.

3 protein chip experiment

See figure 1 for experimental principles.

3.1 reagents required for the experiment:

1) sealing liquid: 3mL of 10% BSA, 7mL of 1 XPBS solution, mixed well and placed on ice.

2) Serum incubation liquid: 1mL of 10% BSA was added to 9mL of 1 XPBST solution, mixed well and placed on ice.

3) Cleaning solution: 1 XPBST, stored in a refrigerator at 4 ℃.

4) secondary antibody incubation solution: including a fluorescently-labeled anti-human IgM secondary antibody (cy 5-labeled, appearing red) and a fluorescently-labeled anti-human IgG secondary antibody (cy 3-labeled, appearing green).

3.2 specific Experimental procedures for protein chips

(a) Rewarming: taking out the chip from a refrigerator at-80 deg.C, re-warming in a refrigerator at 4 deg.C for half an hour, and re-warming at room temperature for 15 min.

(b) And (3) sealing: and fixing the rewarming chip in 14blocks in a fence, adding sealing liquid into each block, placing the blocks on a side swing shaking bed, and sealing for 3 hours at room temperature.

(c) Incubation of serum samples: after the sealing is finished, the sealing liquid is poured out, then the prepared serum incubation liquid is quickly added, 14 samples are incubated on each chip (the samples are frozen and thawed in a chromatography cabinet at 4 ℃ and diluted in a ratio of 1: 50), the sample loading volume of each serum sample is 200 mu L, and the side shaking table is 20rpm and is used for overnight incubation at 4 ℃.

(d) Cleaning: taking out the chip and the chip clamp together, sucking out the sample, then quickly adding the PBST with the same volume, and repeating the steps for a plurality of times to ensure that no cross contamination exists among the serum samples when the chip clamp is detached. After the chip clamp was removed, the chip was placed in a chip washing cassette containing washing solution, and washed on a horizontal shaker at room temperature at 80rpm for 3 times, each time for 10 min.

(e) And (3) secondary antibody incubation: the chip was transferred to an incubation box containing 3mL of secondary antibody incubation solution, and the shaking table was shaken laterally at 40rpm, protected from light, and left at room temperature for 60 min.

(f) cleaning: the chip was removed (note that the upper surface of the chip was not touched or scratched), placed in a chip washing cassette to which a washing solution was added, and washed 3 times at 80rpm for 10min each time on a horizontal shaker. After completion with ddH₂o washing for 10min 2 times.

(g) And (3) drying: the chip is placed in a chip drier for centrifugal drying.

(h) Scanning: operating according to the operating specifications and instructions of the scanner.

(i) data extraction: and aligning the chip image and each array of the result as a whole, pressing an automatic alignment button, and extracting and storing data.

(j) And carrying out data preprocessing.

(k) performing data analysis, firstly screening according to AUC >0.5 and P <0.05, and obtaining the final lung cancer serum marker according to Logistic regression analysis, wherein the protein chip experiment screens out the following serum protein markers: the proteins encoded by the cancer driver genes TP53, P62, NPM1, Survivin, GNA11, HIST1H3B, SRSF2, FGFR2, PBRM1, JAK2, TSC1 and PIK3CA (FIG. 2 is a ROC curve analysis chart of lung cancer diagnosis by 12 TAAs individually screened from the above protein chip, in which (1) - (12) are ROC curves of lung cancer diagnosis by proteins individually encoded by TP53, P62, NPM1, Survivin, GNA11, HIST1H3B, SRSF2, FGFR2, PBRM1, JAK2, TSC1 and PIK3CA in this order; FIG. 3 is a dispersion of SNR values of the above 12 TAAs, in which N represents Normal, i.e., a healthy Normal map, and LC represents lung cancer case. Wherein, the proteins coded by TP53, P62, NPM1, Survivin, GNA11, HIST1H3B, SRSF2, FGFR2, PBRM1, JAK2, TSC1 and PIK3CA genes sequentially have amino acid sequences shown in SEQ ID NO. 1-12.

4 ELISA Experimental verification

See figure 4 for experimental principles.

The specific experimental steps are as follows:

a) Coating: coating was performed at the concentrations in Table 1 at 100. mu.L/well overnight at 4 ℃.

b) And (3) sealing: PBST (PBS, Tween20 Solebao, Beijing) solution of 2% BSA (Solebao, Beijing, analytical pure), 200. mu.L/well, overnight at 4 ℃.

c) Cleaning: wash 3 times at 350 μ L/well PBST.

d) Primary antibody incubation: after the serum was diluted with 1% BSA in PBST 1:100, 100. mu.L/well was placed in a half-water bath at 37 ℃ for 1 h.

e) Cleaning: wash 5 times at 350 μ L/well PBST.

f) And (3) secondary antibody incubation: HRP-labeled mouse anti-human IgG (Olympic, Wuhan) was diluted with 1% BSA in PBST 1:10000, 100. mu.L/well, and half-water-bath at 37 ℃ for 1 h.

g) cleaning: wash 5 times at 350 μ L/well PBST.

h) Color development: TMB color development system, mixing solution A (Solebao, Beijing, analytical pure) and solution B at a ratio of 1:1, and making 100 μ L/well, and keeping in dark at room temperature to obtain desired color (about 5-15 min).

i) And (4) terminating: absorbance was measured within 10min after 50. mu.L/well of 10% concentrated sulfuric acid.

j) Measuring the absorbance: by OD₄₅₀-OD₆₂₀For relative OD values, the blank control was then subtracted, and IgG was normalized and then subjected to subsequent data processing (details of data processing are shown in "5 data processing" sections b) -d) described below).

The coating concentrations of the 12 TAAs screened by the protein chip experiment when the 12 TAAs are subjected to ELISA experiment verification are shown in table 1 below, and the arrangement table of the 96-well plate of the ELISA experiment is shown in table 2 below. In table 2, the positive quality control refers to serum with a higher OD value of the ELISA experiment and positive corresponding antibody through Western Blot experiment verification, the negative quality control refers to serum with an OD value near the mean value of the ELISA experiment in normal control population and negative through Western Blot verification, the blank is serum diluent, human IgG-1-human IgG-8 are human IgG antibodies diluted in a gradient manner, and the concentrations are 10, 20, 50, 100, 150, 200, 250 and 300ng/ml in sequence.

TABLE 1 coating concentrations of each of the 12 TAAs selected

Table 2 96-well plate arrangement for ELISA experiments

the experimental results are as follows: 12 TAAs were detected by ELISA and the results are shown in FIGS. 5 and 6. FIG. 5 is a ROC curve analysis chart of 12 TAAs individually diagnosing lung cancer in ELISA validation experiment, in which (1) - (12) are ROC curves of individually diagnosing lung cancer by the protein encoded by TP53, P62, NPM1, Survivin, GNA11, HIST1H3B, SRSF2, FGFR2, PBRM1, JAK2, TSC1 and PIK3CA in sequence; FIG. 6 is a graph showing the distribution of OD value scatter of 12 TAAs in ELISA validation experiment, in which N represents Normal, i.e., healthy Normal serum, and LC represents lung cancer, i.e., lung cancer case.

As can be seen from FIG. 5, the area under the ROC curve for diagnosing lung cancer by a single index is 0.524-0.812, and the sensitivity range is 19.4% -61.3% when the lowest specificity is ensured. Wherein the area under the curve of GNA11 is maximum and is 0.812, the sensitivity reaches 54.8%, and the specificity is 90.3%; the area under the ROC curve of JAK2 is 0.811, the sensitivity reaches 60%, and the specificity is 90.3%; the area under the ROC curve of P62 was the smallest, 0.524, the sensitivity 23.9% and the specificity 90.3%. As can be seen from FIG. 6, the 12 index OD values were distributed between 0 and 1, the median OD values were substantially evenly distributed between 0.2 and 0.4, and the differences between the healthy controls and the lung cancer cases were statistically significant.

5 data processing

The differential expression protein is screened out by using the focused array human protein chip in a lung cancer group and an NC normal control group through statistical data analysis, and the specific method is as follows:

(1) The initial screening result of the chip is obtained through Focused Array protein chip experiment.

(2) And (3) stability analysis: in the experimental process, the test samples test are repeated according to different time, different chips and different positions so as to evaluate the stability of different chips at different time.

(3) data analysis and results: samples after high background and extreme sample interference were rejected and 180 proteins of each of the IgG and IgM response types were subjected to consistent statistical analysis with the following analysis logic:

a) In order to eliminate the situation of signal nonuniformity caused by inconsistent background values among different protein points in the same chip, the background normalization method is used for processing, the ratio of the foreground value to the background value of each protein, namely F/B, is realized, SNR (signal to noise ratio), namely the mean value of the F/B of two repeated proteins, is defined on the basis, and subsequent statistical analysis is carried out.

b) Assuming that samples needing to be aligned are respectively from two identical populations, and whether the two groups of variances needing to be aligned are homogeneous is determined through an F test, then the F test result is selected to correspond to a t test, and the t test result is characterized by P-value. By definition, when p-value <0.05, the original hypothesis is rejected, i.e. there is a significant difference between the two.

c) For any protein, fold change, which is the difference between the cancer group and the normal group, was calculated to indicate the difference between the two groups.

d) for any protein, according to the diagnostic significance of the two groups compared, firstly, defining cutoff-1.5 as a positive judgment threshold, namely, when the SNR of a sample on the protein is more than or equal to 1.5, the protein is a positive protein; then, based on the control group, setting a proper cutoff threshold, calculating the difference of the positive rate of the cancer group and the control group at the cutoff threshold, and taking the maximum difference as the positive rate of the protein in the compared cancer group to search the high response protein specific to the control group in the cancer group, and finally, defining that the positive rate is not lower than 15%.

e) Based on the above logic, the lung cancer group (100 primary lung cancer patient sera collected from the first subsidiary hospital of the Beijing Youran Hospital and Zheng State university) and the Youran control group (50 normal sera of Youran Hospital) are compared, differential proteins which are obviously higher than those of the control group are selected as candidate markers of the lung cancer, and finally 12 serum protein markers (TP53, P62, NPM1, Survivin, GNA11, HIST1H3B, SRSF2, FGFR2, PBRM1, JAK2, TSC1 and PIK3CA) are selected by a chip to evaluate the diagnostic value of the lung cancer.

Wherein, the protein coded by TP53 gene has an amino acid sequence shown as SEQ ID NO.1, the protein coded by P62 gene has an amino acid sequence shown as SEQ ID NO.2, the protein coded by NPM1 gene has an amino acid sequence shown as SEQ ID NO.3, the protein coded by Survivin gene has an amino acid sequence shown as SEQ ID NO.4, the protein coded by GNA11 gene has an amino acid sequence shown as SEQ ID NO.5, the protein coded by HIST1H3B gene has an amino acid sequence shown as SEQ ID NO.6, the protein coded by SRSF2 gene has an amino acid sequence shown as SEQ ID NO.7, the protein coded by FGFR2 gene has an amino acid sequence shown as SEQ ID NO.8, the protein coded by PBRM1 gene has an amino acid sequence shown as SEQ ID NO.9, the protein coded by JAK2 gene has an amino acid sequence shown as SEQ ID NO.10, and the protein coded by TSC1 gene has an amino acid sequence shown as SEQ ID NO.11, the protein coded by the PIK3CA gene has an amino acid sequence shown in SEQ ID NO. 12. The information sources of the above 12 genes are shown in Table 3 below.

TABLE 3 information sources of the above 12 genes

(4) the ELISA experiment verification is carried out on 12 serum protein markers screened by the protein chip: the method comprises the steps of verifying the samples of the submission chip and verifying the samples collected outside the submission chip again, thereby realizing the verification of the protein chip and ensuring the popularization.

(5) The experimental results are as follows: ELISA experimental verification is carried out on 12 serum protein markers screened by a protein chip, 70% of total population is extracted as a training set by using a random sampling method for all verified population, a disease prediction model is constructed by using binary logistic regression, indexes are screened by using three methods of Forward (Forward: conditional), Backward (Backward: conditional) and direct input method (Enter), 6, 8 and 12 proteins Enter the model respectively, and the corresponding area under the ROC curve (AUC), sensitivity (Se) and specificity (Sp) are shown in the following table 4.

TABLE 4 model indices screened by different screening methods

For the analysis of the diagnostic value and the economic benefit of the model constructed above, the model containing 6 indexes (TP53, NPM1, GNA11, JAK2, TSC1 and PIK3CA) has the best effect, and is verified in the rest 30% of people (verification set), as shown in FIGS. 7 and 8, the area under the ROC curve of the combined diagnosis lung cancer reaches 0.922, 95% CI is 0.870-0.974, and when the specificity is ensured to be 91.5%, the sensitivity is 70.7%, and the consistency rate reaches 81.1%.