Biomarker analysis
tumor, PD‐L1 tumor, PD‐L1
TUMOR, APPENDIX
Before treatment initiation, tumor tissue samples from initial diagnosis or post‐resistance biopsy were collected for evaluation of PD‐L1, CD4, CD8, CD163, Foxp3, and LAG3 expression in the tumor microenvironment. PD‐L1 expression was measured by a 22C3 pharmDx assay (Agilent Technologies), and PD‐L1 positivity (PD‐L1+) was defined as a PD‐L1 tumor proportion score (TPS) ≥1%. CD4, CD8, CD163, Foxp3, and LAG3 staining on immune cells was reported as the proportion of positive cells among all nucleated cells in the stromal compartments, and scoring was recorded as negative (<10%) or positive (≥10%).Epidermal growth factor receptor mutations were assessed by using amplification refractory mutation system polymerase chain reaction (ARMS‐PCR; Amoy Diagnostics) or next‐generation sequencing (NGS, Burning Rock Biotech and Nanjing Geneseeq Technology Inc.). Among them, 12 patients were detected by ARMS‐PCR and nine patients by NGS. The details of targeted NGS data are described in the Appendix 