MTOR and rheumatoid arthritis: Tan IIA suppressed the growth of breast cancer MCF-7 cell line through arresting the S and G2 phase cell cycle by inhibiting the phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt), mammalian target of rapamycin (mTOR), protein kinase C (PKC), rheumatoid arthritis (Ras), and mitogen-activated protein kinase (MAPK) signaling pathway.