Gastric Cancer Marker Detection and Its Kit Development

1 Preliminary screening of early gastric cancer markers and antibody verification

(1) Recruitment and sample preparation of patients and healthy people: This project requires four batches of subjects, three batches of healthy people, early gastric cancer and advanced gastric cancer groups, with an average of 30 cases in each group. The other batch (the second batch) is healthy people and 30 cases of chronic atrophic gastritis, early gastric cancer and 30 cases of chronic atrophic gastritis. There were 100 cases in each of the advanced gastric cancer group, and 20 cases in each of liver cancer, colorectal cancer, and breast cancer. Serum and plasma samples obtained from subjects are used to screen potential gastric cancer tumor markers, verify the practicability of established gastric cancer tumor marker diagnostic models and test kits.

• Recruitment of gastric cancer patients: 30 cases of early gastric cancer patients (T1, T2) and advanced gastric cancer patients (T3, T4) are selected respectively. The staging of gastric cancer is based on the eighth edition of UICC (International Union Against Cancer) TNM staging. Subjects were screened according to the requirements of the informed consent form.
• Recruitment of healthy people: 30 volunteers without underlying diseases are selected as healthy control group. Subjects were screened according to the requirements of the informed consent form.
• Sample preparation: intravenous collection to obtain whole blood samples of patients and healthy controls. The sample requirement for each subject is 600ul of serum and plasma.

(2) Antibody chip screening for potential tumor markers of gastric cancer for the first time In order to screen for potential protein markers of gastric cancer, Raybiotech's high-throughput quantitative antibody chip (AAH-BLG-2000) was used to measure 640 in the first batch of subjects (early gastric cancer, advanced gastric cancer, and healthy controls each 30). Kind of human protein. Preliminarily screen out differential proteins, conduct bioinformatics analysis, and finally screen differentially expressed proteins relevant to the research.

2Customized antibody chip to verify gastric cancer tumor markers In order to further verify the candidate tumor markers for the diagnosis of gastric cancer, the differential proteins screened in the previous stage were customized for antibody chips. Use subject serum samples (second batch) for potential biomarker verification. According to the test results, the poorly specific proteins are discarded, and the more specific proteins are retained.

• Establishment of diagnostic model Use regression analysis to combine and compare multiple differential proteins, perform quantitative analysis, establish a standard curve, establish a diagnostic model for highly specific differential proteins, and further measure the practicability of the highly specific differential protein diagnostic model.

4 Kit development Monoclonal antibodies were produced as capture antibodies for various high-specific tumor markers, and finally a gastric cancer diagnosis kit was established and promoted in clinical practice.

Establishment and performance measurement of gastric cancer diagnostic kit.

• Establish gastric cancer diagnostic kits, quality control reference materials and formulate relevant standards on the basis of the above research results.
• Precision testing: Dilute the self-made quality control reference materials to 3 concentrations of high, medium, and low, each with 3 replicate holes, repeat the test 10 times, and calculate the mean, standard deviation, and test value of each quality control reference product. Coefficient of Variation (CV) value.
• Sensitivity detection: Take the zero reference standard (specific difference protein) as the sample, and substitute the average value of the fluorescence value measured 20 times plus 2 times the standard deviation into the standard curve equation to calculate the minimum detection volume.
• Stability test: Divide the self-made kits into two groups and place them in a 4℃ freezer for 6 months and 37℃ for 7 days. The physical appearance of the kit, the linearity of the dose-response curve, accuracy, sensitivity, and minimum detection volume And other indicators are measured, and the specific detection method is the same as the above steps (2) and (3).
• Comparison with other gastric cancer detection methods: use self-prepared detection kits to detect 30 cases of early gastric cancer serum samples, 30 cases of advanced gastric cancer serum samples, and 30 healthy human serum samples, and analyze the test results.
• Promotion and optimization of the kit. Random sampling is performed among patients using this kit to observe the diagnosis rate of early clinical gastric cancer and the corresponding prognosis, and analyze the results of the return visit. According to the results of the return visit, continue to conduct corresponding experiments to optimize the performance of the kit, for example: improve its accuracy, sensitivity, and so on.

Inclusion criteria

patient

• Age is greater than or equal to 18 years old (including 18 years old);
• Patients who are diagnosed with cancer after pathological diagnosis;
• Can provide enough tissue samples;
• Have not received anti-tumor treatment in the past;
• Comply with the principle of informed consent and sign the informed consent form.

healthy person:

• Age is greater than or equal to 18 years old (including 18 years old);
• No underlying disease;
• Can provide enough tissue samples;
• Comply with the principle of informed consent and sign the informed consent form.

Exclusion criteria

• The tumor foci cannot be clearly derived from a specific tumor type;
• Those who have a history of other tumors, autoimmune diseases and allergies;
• Previously received anti-tumor treatments such as surgery, chemotherapy, radiotherapy, molecular targeted therapy, immunotherapy, biological therapy or Chinese medicines with anti-cancer and anti-tumor effects in the instructions;
• Participated in any clinical trial within 90 days before the experiment;
• Received major surgery within 90 days before the experiment;
• Received bone marrow transplantation 90 days before the experiment;
• Subjects who may not be able to complete the study due to other reasons or who are determined by the investigator to be unsuitable to participate in this study.