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

Table 2

The nomenclature of CYP2A6 and allele frequencies in population.

Allele	Frequencies in population							Nucleotide change	Effect	Enzyme activity
	Caucasian (%)	African American (%)	Swedes (%)	Finns (%)	Spaniards (%)	Chinese (%)	Japanese (%)			In vitro	In vivo
CYP2A6*1A	66.5	—^a	98.9	98.6	97.0	43.2	40.0–42.0	None	—	Normal	Normal
CYP2A6*1B	30.0	—	—	—	—	40.6	38.0–41.0	Gene conversion at 3′-flanking region	—	—	—
CYP2A6*1 × 2	0.7	—	—	—	—	0.4	0.0	—	Duplication of CYP2A6	—	—
CYP2A6*2	1.1–3.0	0.3	1.1	1.4	3.0	0.0–0.7	0.0	488 T→A	L160H	None	None
CYP2A6*3	—	—	—	—	—	—	—	CYP2A6/CYP2A7 hybrid	—	—	—
CYP2A6*4A	0.5–4.9	—	—	—	—	6.6–15.1	20.0–31.0	CYP2A6 deletion	CYP2A6 deletion	—	None
CYP2A6*4B	—	—	—	—	—	—	—	CYP2A6 deletion	CYP2A6 deletion	—	None
CYP2A6*4C	—	—	—	—	—	—	—	—	—	—	—
CYP2A6*4D	—	—	—	—	—	—	—	CYP2A6 deletion	CYP2A6 deletion	—	None
CYP2A6*5	0.0–0.2	—	—	—	—	1.0	0.0	1436 G→T	G479V	None	None
CYP2A6*6	—	—	—	—	—	—	0.4	383 G→A	R128Q	Down	—
CYP2A6*7	1.0	—	—	—	—	2.2	6.3	1412 T→C; gene; conversion at the; 3′-flanking region	I471T	Down	Down
CYP2A6*8	0.0	—	—	—	—	3.5	1.6	1454 G→T; gene; conversion at the; 3′-flanking region	R485L	—	Normal
CYP2A6*9	5.2	—	—	—	—	15.7	—	—48 T→G	TATA box	Down	—
CYP2A6*10	0.0	—	—	—	—	0.4	1.6	1412 T→C; 1454 G→T; gene conversion at the; 3′-flanking region	I471T; R485L	—	Down
CYP2A6*11	—	—	—	—	—	—	—	670 T?C	S224P	Down	Down

Adapted from [57, 60, 61].
^aThe data not reported.