A closer look at the leading-edge genes in the heme metabolism pathway revealed many genes that are relevant for cancer biology including antigen processing (CTSE), cell adhesion (ICAM4), TLR signaling (MFHAS1), neutrophil chemotaxis (MPP1), metabolism (ACSL6, PC, HAGH), cytokine production/regulation (TMEM9B, USP15, RIOK3), and apoptosis (BNIP3L, HTATIP2) (Supplementary Fig. 3B). This evidence concerns the gene CTSE and cancer.