HTRA1 and ovarian cancer: HTRA1 increases cell sensitivity to the cytotoxicity of paclitaxel and cisplatin via degrading X‐linked inhibitor of apoptosis protein (XIAP).67, 68, 69 The expression level of XIAP is negatively correlated with HTRA1 expression in hepatocellular carcinoma cells.67 In addition, down‐regulation of HTRA1 expression in the ovarian cancer cell is related to the poor outcome of patients with chemotherapy.68