(24) Tramadol confers an anti-tumorigenic effect against proliferation, migration and invasion in lung cancer cells by upregulating the phosphatase and tensin homolog and interfering with phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signaling (25) and by downregulating the α2-receptor in breast cancer cells (MDA-MB-231) (14); our results are consistent with the abovementioned findings. This evidence concerns the gene PTEN and breast cancer.