Firstly, using siRNA, we reduced MAP3K1 expression in two PIK3CA-mutant tumor cell lines (MCF7 and T47D) and in a breast cell line (MCF10A) that had been genetically engineered to express a common PIK3CA (H1047R) mutant (hereafter referred to as MCF10A-PI3KαH1047R). This evidence concerns the gene MAP3K1 and neoplasm.