Mutations in APC, CTNNB1 and K-ras genes and expression of hMLH1 in sporadic colorectal carcinomas from the Netherlands Cohort Study

Table 4 Comparisons between patients with an APC and/or K-ras mutation and absent hMLH1 expression.

	APC ^b and/or K-ras ^c mutation		Absence of hMLH1		P-value
Number of patients^a	360		47
Age at diagnosis (yr, mean (SD))	67.8	(4.2)	69.3	(4.3)	0.03
Sex (% male)	58		40		0.02
Family history of colorectal cancer (% yes)	8		11		0.60
Tumour sub-localisation					<0.001
Proximal colon	96	(70%)	41	(30%)
Distal colon	107	(97%)	3	(3%)
Rectosigmoid	51	(100%)	0	(0%)
Rectum	100	(97%)	3	(3%)
Dukes' stage					0.08
A	86	(90%)	10	(10%)
B	117	(84%)	23	(16%)
C	89	(91%)	9	(9%)
D	47	(94%)	3	(6%)
Differentiation					<0.001
Good	37	(92%)	3	(8%)
Moderate	232	(92%)	20	(8%)
Poor	43	(78%)	12	(22%)
Undifferentiated	1	(33%)	2	(67%)

^a Patients with both absent hMLH1 expression and an APC or K-ras mutation were excluded from the analysis.
^b APC mutations: only mutations resulting in a stop codon.
^c K-ras mutations: only activating mutations in codon 12 or 13.

ISSN: 1471-2407