At present, 34 countries in the world have carried out paid immunotherapy, and neighboring countries and advanced countries such as Japan and South Korea have successively carried out paid immunotherapy and first-line and second-line treatment for advanced non-small cell lung cancer; The National Cancer Information Network of the United States also suggested in the NCCN guidelines that the clinical application of immunotherapy will be decided according to the performance of tumor PD-L 1. So how do PD-L 1 detect and judge whether the subject will get cancer? Cai Wenquan, director of the Third General Pathology Department, particularly emphasized the importance of PD-L 1 biomarker detection.

What is an immune checkpoint PD-L 1/PD- 1?

Cai Wenquan said that protein at the immunization checkpoint is like the checkpoint at the ancient city gate. When PD-L 1 or PD- 1 (programmed cell death protein 1 and ligand) and identity checking are completed, it will be released and enter the cell. Many cancer cells use this feature to inhibit the activation of T cells, help cancer cells avoid the recognition and attack of T cells, and make cancer cells proliferate rapidly.

Let PD-L 1 or PD- 1 help to inhibit cancer cells, just like blocking the role of identity check, cancer cells cannot grow and spread. To put it simply, once PD-L 1 and PD- 1 are combined, T cells will not attack tumor cells, and the immune checkpoint inhibitor is to block the combination of PD-L 1 and PD-L 1, so that T cells can recover their immunity and launch sustained attacks on tumor cells.

Pathological examination before, during and after cancer treatment

Cai Wenquan said that in order to accurately treat cancer, patients should go through layers of pathological examination before starting treatment:

1. Tissue removal: with the assistance of medical teams such as internal medicine, surgery and radiology, tumor tissue is removed.

2. Biomarker detection: Pathology department carries out tissue section to confirm the diagnosis. After that, the clinician was diagnosed with cancer, and further asked for biomarker detection of EGFR or ALK.

3. Treatment and diagnosis: Pathology department provides test results, such as positive or negative. Is the patient sensitive to treatment? Clinicians will treat patients according to the diagnosis, and then the multidisciplinary treatment team will discuss the treatment plan, and then evaluate the most suitable treatment plan for patients.

PD-L 1 biomarker improves the accuracy of immunotherapy and screens out patients who can be treated with immune checkpoint inhibitors.

Cai Wenquan said that many clinical studies have found that the evaluation of PD-L 1 in specific tumor types can help doctors screen out subjects who respond to inhibitor treatment at immune checkpoints. The higher the expression of PD-L 1, the better the therapeutic effect. Moreover, the international guidelines for the treatment of lung cancer have added PD-L 1 detection suggestions. The expression of PD-L 1 is detected by the principle of immunohistochemical staining. It has different expression in different tumor cells, so there are different scoring methods. Tumor proportion score (TPS) will be used to detect patients with non-small cell lung cancer, and comprehensive positive score (CPS) will be used to detect gastric cancer and esophageal cancer. PD-L 1 is the most convenient, fast and economical detection method at present, and the result can be known in one week.