A key enzyme in this process is SNM1A, a 5′-3′ exonuclease which hydrolyses the phosphodiester backbone of the DNA past the site of the ICL.8, 9 Cells deficient in SNM1A show increased sensitivity to crosslinking agents such as SJG-136 and the anticancer drug mitomycin C.10SNM1A is therefore a promising drug target, as inhibitors of this enzyme could be used to resensitise chemotherapy-resistant tumours. The gene discussed is DCLRE1A; the disease is neoplasm.