原发乳腺癌与配对转移灶之间 PD-L1 表达和 TIL（肿瘤浸润淋巴细胞）的比较分析：对免疫治疗的意义

IHC analysis of 50 paired primary and metastatic lesions revealed distinct PD-L1+ TIL expression patterns across different molecular subtypes of breast cancer. Patients with PD-L1+ tumors showed significantly shorter median disease-free survival (DFS) and overall survival (OS) compared to those with PD-L1- tumors. We observed significant differences in the immune microenvironment between primary and metastatic sites, with metastatic lesions showing consistently lower TIL density, PD-L1+ TIL density, and tumor PD-L1 expression compared to matched primary tumors.

Our findings demonstrate systematic differences in immune parameters between primary and metastatic breast cancer sites, with reduced immune infiltration in metastatic lesions. The data suggest that targeting the PD-1/PD-L1 pathway may be particularly beneficial in patients with PD-L1+ TIL-high primary tumors, potentially by reinvigorating anti-tumor immune responses.