Loss of heterozygosity on long arm of chromosome 22 in sporadic colorectal carcinoma

Table 1 LOH frequency of 5 microsatellite markers on the long arm of chromosome 22

Locus	Location	LOH case	Normal case	LOH rate (%)	Informative rate (%)
D22S315	22q12.1	12	56	17.65	81.93
D22S280	22q12.2-12.3	20	37	35.09	68.67
D22S283	22q12.3-13.1	17	43	28.33	72.29
D22S423	22q13.2	15	41	26.79	67.47
D22S274	22q13.32-13.33	16	31	34.04	56.63

Table 2 Clinicopathological features of 8 cases of sporadic colorectal carcinoma who behaved LOH in all informative loci

No	Gender	Age	Location	Gross Pattern	Size (cm)	Differentiation	Dukes stage
125	Female	52	Sigmoid Colon	Ulcerative	5.5 × 4	Moderately	A
128	Male	70	Descending Colon	Ulcerative	4 × 4.5	Moderately	C
134	Female	70	Ascending Colon	Massive	5 × 5.5	Moderately	C
137	Female	76	Sigmoid Colon	Ulcerative	6 × 6	Moderately	C
138	Female	66	Rectum Colon	Ulcerative	3 × 3	Well	A
210	Female	41	Ascending Colon	Massive	5 × 4	Well	A
220	Female	79	Ascending Colon	Massive	7 × 4	Well	B
223	Male	63	Rectum	Encroaching	6 × 6.5	Moderately	D

Table 3 The relationship between clinicopathological features and LOH of 5 loci on chromosome 22

		D22S315		D22S280		D22S283		D22S423		D22S274
		N	L	N	L	N	L	N	L	N	L
Gender	Male	28	6	19	7	21	7	22	5	13	8
	Female	28	6	18	13	22	10	19	10	18	8
Age	> 60	41	9	24	19	31	15	30	11	22	13
	≤ 60	15	3	13	1	12	2	11	4	9	3
Location	Proximal Colon	21	4	13	7	18	5	14	6	15	2
	Distal Colon	13	4	12	4	11	5	12	6	7	5b
	Rectum	22	4	12	9	14	7	15	3	9	9a
Gross Pattern	Massive	23	4	16	8	19	7	16	6	11	5
	Ulcerative	21	7	15	9	14	7	18	7	14	8
	Encroaching	12	1	6	3	10	3	7	2	6	2
Size	≥ 5 (cm)	25	7	14	11	20	8	18	10	17	5
	< 5 (cm)	31	5	23	9	23	9	23	5	14	11
LN Metastasis	LN (+)	36	9	26	13	31	11	26	11	24	7
	LN (-)	20	3	11	7	12	6	15	4	7	9
Differentiation	Well	15	3	8	6	13	3	11	5	7	5
	Moderately	28	3	17	10	19	10	24	5	15	7
	Poorly	3	3	4	2	3	1	1	2	3	3
	Mucinous	10	3	8	2	8	3	5	3	6	1
Dukes stage	A	3	3	1	3	3	2	3	2	2	4
	B	17	1	10	4	9	4	12	2	5	5
	C	26	4	18	11	22	9	19	7	16	5
	D	10	4	8	2	9	2	7	4	8	2

^aP = 0.018, the LOH frequency of rectal cancer vs that of proximal colon cancer;

^bP = 0.015, the LOH frequency of cancer in distal colon and rectum vs that of proximal colon cancer