With exception of VANGL2, up-regulation of the genes involved in Wnt signaling pathway, namely WNT5A, MSX2, TCF7L2 and TNFRSF11B, was confirmed in the validation set, further emphasizing the important role of the Wnt signaling pathway in PIK3CA-mutated breast cancer. This evidence concerns the gene TNFRSF11B and breast carcinoma.