Moreover, administration of these supplements to pregnant mothers might rescue embryonic anaemia caused by inactivation of SHMT2. By contrast, activation of SHMT2 or intake of these supplements might enhance tumour growth due to the fact that SHMT2 is activated in certain human tumour cells, and that its disruption suppresses tumour growth, as well as respiratory function15,16. This evidence concerns the gene SHMT2 and anemia.