Gene expression profiles of PD-L1 SP142 expression in triple-negative breast cancer. Gene expression profiles of PD-L1 SP142 expression in triple-negative breast cancer

The SP142 PD-L1 assay is a companion diagnostic for atezolizumab in metastatic triple-negative breast cancer (TNBC). The VENTANA SP142 assay was used to identify PD-L1 expression from TMA slides where PD-L1-positivity for an individual sample was defined as ≥1% of tumor-infiltrating immune cells as having PD-L1 expression. The PD-L1-positive gene signature consisted of 94 immune-related genes. The PD-L1-positive signature was predictive of pathologic complete response and survival outcome in multiple TNBC cohorts. In other malignancies treated with ICIs, the PD-L1-positive signature was associated with response and improved survival. Overall design: We prospectively collected tumor tissues from specimens of surgically resected breast cancer at the Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, between July 1997 and December 2007. A total of 82 patients with triple negative breast cancer were enrolled for gene expression profiling.