FECH and acute myeloid leukemia: As FECH expression did not change, this study suggested that the accumulated PpIX resulted from the inability of FECH to keep pace with the increased flux of the haem pathway.75 Using gene set enrichment analysis, a cohort of acute myeloid leukaemia (AML) patients had a strong correlation between oncogene MYCN expression and upregulation of haem pathway enzymes.77