PPIG and neoplasm: Previous studies showed that CYP20A1 is expressed in the human hippocampus and substantia nigra, suggesting its involvement in brain and early development.52 As far as we know, CYP20A1 was considered as “orphan” CYP with no functional information.53 Therefore, the mechanism of rs2043449 affecting tumor susceptibility in these subgroups remains unclear; further functional analysis of CYP20A1 in these subgroups may help to clarify the relevant genetic effects of LC pathogenesis.