Table 1.

Examples of pharmacogenomic candidate genes and the frequency of variants of these genes within Caucasian and African-American populations.

Gene	Variant	Frequency Caucasian (%)	Frequency African-American (%)	Ref.
ABCB1 (MDR1)	MDR1*2	27	6.5	[51]
ABCG2	ABCG2 -421C>A	12	1-5	[51]
DPD	IVS14+1G>A	0.91		[52]
ERCC1	ERCC1-496C>T	58	0	[51]
ERCC2	ERCC2 -2251A>C	44	16	[51]
GSTP1	GSTP1 -105	33	42	[53]
MTHFR	MTHFR -677C>T	36	13	[54]
TPMT	TPMT*2	0.17-0.5	0.4	[55]
	TPMT*3A	3.2-5.7	0.8
	TPMT*3C	0.17-4.8	2.4
TS	TSER*2	40	46	[56,57]
UGT1A1	UGT1A1*28	45	39	[58]
XRCC1	XRCC1-1301	35	36	[51]