To evaluate the possible predictive value of COL6A1 on clinical response to PD-1 inhibitor immunotherapy in BC, COL6A1 protein expressions were detected in 58 patients with advanced or metastatic BC who received Tislelizumab immunotherapy….we found that the ORR was 53.8% and DCR was 84.6% in the low-expression group of COL6A1, while the ORR was 20% and DCR was 75.6% in the high-expression group of COL6A1....suggesting that BC patients with high expression of COL6A1 had poor response to PD-1 inhibitor immunotherapy in the short-term curative effect and COL6A1...