The phosphoinositide 3-phosphorylated Akt-mechanistic target of rapamycin (PI3K-Akt-mTOR) signaling pathway inhibitor-sensitive–mesenchymal subtype, the first subtype, is typically characterized by the pathological feature of tumor stem cell-like heterotypic cells, indicating that drugs targeting the PI3K-Akt-mTOR pathway may be effective treatments for this subtype. This evidence concerns the gene PIK3CA and neoplasm.