Table 1.

CYP3A family genes and their allelic functions

Gene	Characteristic	Reference
CYP3A4	Cytochrome P4503A4 (CYP3A4) protein facilitates the oxidative deactivation of testosterone to biologically less active metabolites, and the inhibition of CYP3A4 causes increased levels of testosterone. CYP3A4 supports oxidative metabolism of finasteride and may be a effective molecule in PCa treatment. Germline genetic variation in the 5′ regulatory region of the CYP3A4 gene (A to G transition) on chromosome 7 has been reported. This variant G allele (referred to as CYP3A4 G variant) is more common among AA men (gene frequency>50%) than CA (<10%), Hispanic, or Asian men. The G variant is inversely associated with less aggressive PCa. ., and the CYP3A4 variant is strongly associated with AA population.	(167–169) (170, 171) (172)
CYP3A5	CYP3A5 expressed at high levels in the non-tumoral prostate tissue, specifically in the basolateral cells and catalyzes 6β-hydroxylation of testosterone. An A to G transition (A6986G) within intron 3 leads to a variant in the CYP3A5 mRNA expression in human prostatic tissue. Allele CYP3A5*1 (A allele) produces a correctly spliced transcript leading to high levels of full-length CYP3A5 mRNA and protein, however allele CYP3A5*3 (rs776746, G allele) creates a cryptic splice site leading to the inclusion of a novel exon, and ultimately a premature stop codon. CYP3A5*1 has a higher frequency in AA individuals than Caucasian or Asian men. CYP3A5*3/*3 decreases CYP3A5 mRNA content 13-fold compared to CYP3A5*1/*3. CYP3A5*1 and show linkage disequilibrium with CYP3A4*1B in Caucasian and African men, CYP3A4*1B/CYP3A5*1 haplotype is inversely associated with risk among Caucasian men with less aggressive disease. In Japanese population, CYP3A5*1/*1 men have lower risk of developing a low-grade localized PCa than CYP3A5*3/*3 carried men. CYP3A5*3 is not associate with PCa in either white or African men, the CYP3A4*1B/CYP3A5*3 haplotype is significantly associated with increasing PCa risk in European American but not in AA men. CYP3A5 interacts with SRD5A2 or KLK3, which influenced the development of PCa.	(173) (170, 174) (175, 176)
CYP3A43	CYP3A43 is predominantly expressed in the prostate. The allelic frequency of CYP3A43*3 (rs680055) is higher in AA than CA men. There is a 2.6.-fold increase in PCa risk among individuals with the CYP3A43*3 homozygous genotype compared with those with the CYP3A43*1 homozygous genotype in AA, but not in CA men.	(177, 178) (179)