Link between colorectal cancer and polymorphisms in the uridine-diphosphoglucuronosyltransferase 1A7 and 1A1 genes

Table 3 The comparison of UGT1A1 genotypes between case and control groups.

UGT1A1 genotype	Case group (n = 268)		Control group (n = 441)		P (χ2 test)
	Number	%	Number	%
Wild type	121	45.2	218	49.4	0.78
Heterozygous variation	118	44.0	186	42.23
6/71	37		96
211 G to A/normal	76		79
1091 C to T/normal	5		11
Compound heterozygous variation	23	8.6	34	7.7
6/7, 211 G to A/normal	13		6
6/7, 686 C to A/normal	8		20
6/7, 1091 C to T/normal	0		2
6/7, 211 G to A/normal,	1		2
686 C to A/normal 6/7,
686 C to A/normal,	1		0
1091 C to T/normal
211 G to A/normal,	0		4
1091 C to T/normal
Homozygous variation	6	2.2	3	0.7
7/72	1		0
211 G to A/211 G to A	4		3
7/7, 211 G to A/normal	1		0

¹6/7 and

²7/7 represent A(TA)₆TAA/A(TA)₇TAA and A(TA)₇TAA/A(TA)₇TAA in the promoter area of UGT1A1 gene, respectively.

³The expected frequency is 40.7% calculated by Hardy-Weinberg equilibrium: [2×(frequency of wild type)^1/2×(frequency of compound heterozygous variation plus frequency of homozygous variation)^1/2 = 2×49.4^1/2×(7.7+0.7)^1/2 = 40.7]. The observed frequency (42.2%) is not significantly different from the expected frequency (40.7%) (P = 0.89 by χ² test).