Fig. 1: Correlation between XIAP and BRCA1-mutational status.

a Level of expression of XIAP mRNA, evaluated by qPCR, in the BRCA1-mutated ovarian cancer (OC) cell line (CL) UWB1289, BRCA1-restored OC CL UWB1289-BRCA1 and UWB1289-BRCA1 after the silencing of wild-type BRCA1, using siRNA (siBRCA1) (n = 3). b The level of expression of XIAP protein, evaluated by western blot, in the BRCA1-mutated OC CL UWB1289, BRCA1-restored OC CL UWB1289-BRCA1 and in UWB1289-BRCA1 after the silencing of wild-type BRCA1, using siRNA (siBRCA1) (n = 3). c Comparison of the level of expression of XIAP protein, evaluated by western blot, in BRCA1-mutated OC CLs (BRCA1-MUT) and the BRCA1/BRCA2 wild-type OC CLs (BRCA1/2-WT) (n = 3). Effect size: Cohen’s d = (103–67.4)/38.300737 = 0.929486. d Evaluation by RPPA of the level of expression of XIAP protein in ovarian cancers (OCs) from 69 patients treated by primary surgery followed by platinum/taxane chemotherapy. XIAP levels were higher in OCs with BRCA1 mutations (BRCA1-MUT) than in OCs with wild-type BRCA1/2 (BRCA1/2-WT). Effect size: Cohen’s d = (1.174 − 0.949)/0.269438 = 0.835072. e In a separate group of 292 high-grade serous OCs, XIAP levels, as determined by RPPA, were also higher in OCs with BRCA1 mutations (BRCA1-MUT) than in OCs with wild-type BRCA1/2 (BRCA1/2-WT). Effect size: Cohen’s d = (0.4965 − 0.4408)/0.052942 = 1.0521. f In a group of 422 OCs from patients treated with surgery and adjuvant platinum-based chemotherapy, those patients with cancers expressing a level of XIAP protein higher than the median had a significantly improved overall survival. Note that in (a–c), XIAP protein or mRNA intensity in the CLs is calculated as a percentage of that in UWB1289 after normalisation with the level of expression of GAPDH protein or mRNA in the corresponding CLs. d, e XIAP protein intensity values in OCs were quantified by RPPA as described in “"Methods” and the values were visualised in the graphs (d, e) using Tukey boxplots.