RETRACTED ARTICLE: Hypermethylation of the 5′ CpG island of the p14ARF flanking exon 1β in human colorectal cancer displaying a restricted pattern of p53 overexpression concomitant with increased MDM2 expression

Table 3 Distribution and density of p14 ^ARF methylation in tumors and adjacent colon mucosa from patients with colorectal cancer

CpG site	Position relative to ATG	% of methylated clones within the 5′ CpG island flanking exon 1β
CpG site	Position relative to ATG	Tumor samples	Normal colon mucosa	Tumors with diffuse p53 overexpression pattern	Tumors with restricted p53 overexpression pattern
1	−69	13	5	3	17
2	−43	17	1	0	24
3	−40	22	1	0	31
4	−35	25	4	0	36
5	−28	22	2	0	31
6	−22	19	2	0	27
7	−10	22	5	3	30
8	−7	21	3	0	30
9	+4	30	5	3	41
10	+25	41	8	37	43
11	+31	42	12	43	41
12	+34	45	12	50	43
13	+36	43	18	43	43
14	+38	34	12	33	34
15	+42	43	13	43	43
16	+47	41	15	53	36
17	+50	45	9	50	43
18	+52	43	12	57	37
19	+66	47	9	50	46
20	+80	44	9	50	41
21	+82	40	13	37	41
22	+90	38	13	27	43
23	+105	38	13	47	34
24	+114	41	19	50	37
25	+118	34	17	37	33
26	+121	31	24	37	29
27	+133	27	9	13	33

The percentage of methylated clones was calculated in all tumors (n = 10, ≥10 clones analyzed for each tumor) and adjacent normal colon mucosa (n = 10, ≥ 10 clones analyzed for each sample) for every CpG site. The percentage of methylated clones was higher in tumors median 38%, 95% CI 25-41%; range 13-47%), than in normal colon mucosa (median 9%, 95% CI 1 to 24; range 1 to 24%) (Wilcoxon rank sum test, P <0.0001). The percentage of methylated clones on proximal CpG sites was also higher in tumors with a restricted p53 overexpression pattern (median 30%, 95% CI 24 to 36%, range 17 to 36%) than in tumors with a diffuse p53 overexpression pattern (median 0%, 95% CI 0 to 3%, range 0 to 3%) (Wilcoxon rank sum test, P = 0.0003).