PPP2R2A and neoplasm: Despite considerable differences in the baseline characteristics between luminal-like cases in the discovery and validation cohorts, namely regarding age, tumor size and grade (Additional file 1: Table S7), the association between PPP2R2A (B55α) expression status and worse DFS and OS was further confirmed in this subset of patients in the validation cohort with PPP2R2A (B55α)-/ low BC (p = 0.031 for DFS and p = 0.027 for OS).