We showed that FFL (PDGF/FLT1/SHC1) is significantly enriched in the PIK3CA-mutated luminal A tumor patients, and furthermore, that the luminal A tumor patients harboring the PIK3CA mutation and this novel positively regulating loop in their tumors have significantly longer survival than those containing PIK3CA mutation only in their tumors. The gene discussed is SHC1; the disease is neoplasm.