Analogous results were obtained with the CDK12 inhibitor, THZ531 which, in line with the effects observed in CDK12-OE MCF10A cells, inhibited PSAT1 and MTHFD1 expression in CDK12HIGH breast cancer cells both at the mRNA and protein level (Supplementary Fig. 6e). The gene discussed is MTHFD1; the disease is breast carcinoma.