Multivariate Cox regression analysis including validated prognostic factors (lymph node metastases, histological grade, tumour size, ER receptor positivity and HER2 status) and controlling for both endocrine and chemotherapies, demonstrated that membranous PRPF38B expression was an independent predictor of DFS (training set; HR (hazard ratio) [95% CI (confidence interval)): 1.76 (1.04–2.98, p = 0.037 and test set: [HR (95% CI): 1.69 (1.00–2.85, p = 0.048)]. This evidence concerns the gene PRPF38B and metastatic malignant neoplasm in the lymph nodes.