Cytochrome P450 Metabolism of Betel Quid-Derived Compounds: Implications for the Development of Prevention Strategies for Oral and Pharyngeal Cancers

Table 3

The association studies between cytochrome P450 (CYP) polymorphism and betel quid-related oral disorders.

CYP; gene	Cases/number; Controls/ number	Chewing habit of cases/controls	OR (95% CI)	Conclusion	Population/; reference
CYP1A1	Oral cancer/106; Controls/146	BQ, 62.3%/15.0%	Gene effects: Exon 7 A/G (ile/val); A/G versus A/A, 5.08 (2.64–9.76)*; G/G versus A/A, 18.86 (3.61–98.52)*	Subjects with CYP1A1 carrying G allele increased the risk for OPMDs and oral cancer	Taiwan/[29]
	OPMDs/60; Controls/146	BQ, 75.0%/15.0%	Gene effects: Exon 7 A/G (ile/val); A/G versus A/A, 2.67 (1.32–5.40)*; G/G versus A/A, 15.23 (2.76–83.98)*
			Gene effects: 3′UTR MspI site	No significant association
	OSF/75; Controls/150		Gene effects: m1 at MspI site; (+/−) versus (+/+), 2.88 (1.57–5.24)*; (−/−) versus (+/+), 3.16 (1.10–9.04)*; Gene effects: m2 at NcoI site; (−/−) versus (+/+), 8.25 (4.31–15.80)*	Subjects with CYP1A1 polymorphisms had significantly increased risks of OSF	India/[51]
CYP2A6	Oral lesions/286; (15 oral cancer, 62 OSF and 209 leukoplakia); Controls/135	betel, 100%/100%	Gene effects; *1B/*4C versus *1A/*1A, 0.21 (0.05–0.88)*; *4C/*4C versus *1A/*1A, 0.14 (0.03–0.72)*	BQ chewers with activity deficient of CYP2A6 deletion decreased the risk of oral cancer	Sri Lanka/[30]
CYP2E1	Oral cancer/41; Controls/123	BQ, 73.2%/12.2%	Gene effects; c1/c2 + c2/c2 versus c1/c1, 2.0 (0.8–5.4); Among nonchewers; c1/c2 + c2/c2 versus c1/c1, 4.7 (1.1–20.2)*; Among chewers; c1/c2 + c2/c2 versus c1/c1, 0.8 (0.2–3.3)	A significant relationship between CYP2E1 polymorphisms and oral cancer risk was found among non-BQ chewers	Taiwan/[27]
	Oral cancer/106; Controls/146		Gene effects: at PstI site; (+/−) versus (+/+), 3.14 (1.14–8.62)*	Individuals with CYP2E1 at PstI site polymorphism (+/−) may confer a significantly increased risk for oral cancer	India/[51]
CYP26B1	Oral cancer/247; Controls/338	BQ, 85.4%/22.5%	rs707718; Gene effects; A versus C, 1.48 (1.16–1.87)*; AA versus CC, 2.26 (1.35–3.80)*; Gene-BQ (+/−) interplay; AA-BQ (+) versus CC-BQ (−), 70.04 (13.62–360.11)*	BQ chewing interacted with CYP26B1-AA significantly increased the risk of oral cancer	Taiwan/[48]
			Gene effects; rs2241057, rs2286965, rs3768641	No significant findings

OPMDs: oral potentially malignant disorders; OSF: oral submucous fibrosis; betel: betel quid chewing with or without tobacco; BQ: betel quid without tobacco; OR: odds ratios; CI: confidence interval; *statistical significance.