CXCR4 and polycystic ovary syndrome: Interestingly, these analyses revealed the involvement of several genes important for steroidogenesis and PCOS that were altered by metformin treatment, e.g. genes of steroid biosynthesis (HSD17B14, STS, CYP21A2, HSD3B2), GPCR genes (CXCR4, GnRHR, TSHR, MC2R) and PCOS genes (TRIB3, VCAN, ENPP1, ITGA5, PTPRM, SLC2A4, CYR61, ADRA2A, AGTR1, NPY1R and CNR1).