Conclusion
TRIPLE-NEGATIVE BREAST CANCER
Our analysis of biomarkers in the KRISTINE study confirms the role of HER2 and the immune microenvironment in achieving pCR after dual HER2-targeted therapy, with the PAM50 HER2-E subtype, HER2 gene ratio ≥ 4, and PD-L1-positive IHC status being positively associated with pCR. HER2 IHC3+ and PD-L1-positive status were associated with numerically better EFS compared with HER2 IHC2+ and PD-L1-negative status. The observed associations between PD-L1 and clinical outcomes may be related more to their independent prognostic potential than to a relationship with response to HER2-targeted therapeutics, as similar associations have been observed in studies of patients with triple-negative breast cancer [