PHGDH and Familial prostate cancer: Our unbiased lipidomic screening found out the enhanced sphingolipid synthesis by PLK1 in prostate cancer cell line LNCaP, and we confirmed the significant incorporation of exogenous serine into ceramide (Fig. 6B), which accounts for over 1% of detected sphingolipids (Table EV4) in C4–2 PHGDH mutant cells.