HCP5 and cancer: BIRC3 is an inhibitor of apoptosis and as potential oncogene in many cancers through inhibiting apoptosis and facilitating cancer cell survival.34, 35 A potent small‐molecule antagonist of IAP proteins has been discovered as clinical candidate for cancer treatment.36 In this study, we found BIRC3 expression was upregulated in TNBC cells and tumor tissues, which consistent with TCGA database analysis and other reports.26 The BIRC3 expression was also decreased in HCP5 knockdown cells and xenografted tumor tissues.