MutL homolog 1 methylation and microsatellite instability in sporadic colorectal tumors among Filipinos

Table 1 hMLH1 methylation status in the Filipinos colorectal cancer patients

		Normal tissue (%)			Tumor tissue(%)			Normal/tumor (%)
		M	U		M	U		M/M	U/U	M/U or U/M
	Freq	19	35	P value	5	49	P value	4	34	16	P value
Gender
Male	30	9 (30)	21 (70)	NS	2 (7)	28 (93)	NS1	1 (3)	20 (67)	9 (30)	NS
Female	24	10 (42)	14 (58)		3 (12)	21 (88)		3 (13)	14 (58)	7 (29)
Age
≤ 40	5	3 (60)	2 (40)	NS1	0 (0)	5 (100)	NS1	0 (0)	2 (40)	3 (60)	NS
> 40	49	16 (33)	33 (67)		5 (10)	44 (90)		4 (8)	32 (65)	13 (27)
Location of tumor
Proximal	6	4 (67)	2 (33)	NS1	2 (33)	4 (67)	0.031	2 (33)	2 (33)	2 (33)	0.029
Distal/rectum	48	15 (31)	33 (69)		3 (6)	45 (94)		2 (4)	32 (67)	14 (29)
Tumor grade
Poor	8	5 (62)	3 (38)	NS	1 (12)	7 (88)	NS	1 (12)	3 (38)	4 (50)	NS
Moderate	44	13 (30)	31 (70)		4 (9)	40 (91)		3 (7)	30 (68)	11 (25)
Well	2	1 (50)	1 (50)		0 (0)	2 (100)		0 (0)	1 (50)	1 (50)
Tumor stage
I-II	20	6 (30)	14 (70)	NS	2 (10)	18 (90)	NS1	2 (10)	14 (70)	4 (20)	NS
III-IV	34	13 (38)	21 (62)		3 (9)	31 (91)		2 (6)	20 (59)	12 (35)

¹Fisher’s exact test.

NS: Not significant; M: Methylated; U: Unmethylated; In paired normal/tumor tissues: M/M: Methylated/methylated; U/U: Unmethylated/ unmethylated; M/U: Methylated/unmethylated; U/M: Unmethylated/methylated.

Table 2 Microsatellite instability status in the Filipinos colorectal cancer patients

		Normal tissue (%)				Tumor tissue (%)				Normal/tumor (%)
		MSI-H	MSI-L	MSS	P value	MSI-H	MSI-L	MSS	P value	H/H	L/L	S/S	L/S or S/L	L/H or H/L	P value
	Freq	25	23	6		27	17	10		19	8	3	10	14
Gender
Male	30	12 (40)	15 (50)	3 (10)	NS	14 (47)	9 (30)	7 (23)	NS	9 (30)	4 (13)	1 (3)	8 (27)	8 (27)	NS
Female	24	13 (54)	8 (33)	3 (13)		13 (54)	8 (33)	3 (13)		10 (42)	4 (17)	2 (8)	2 (8)	6 (25)
Age
≤ 40	5	3 (60)	2 (40)	0 (0)	NS	2 (40)	1 (20)	2 (40)	NS	2 (40)	0 (0)	0 (0)	2 (40)	1 (20)	NS
> 40	49	22 (45)	21 (43)	6 (12)		25 (51)	16 (33)	8 (16)		17 (35)	8 (16)	3 (6)	8 (16)	13 (27)
Location of tumor
Proximal	6	4 (67)	2 (33)	0 (0)	NS	4 (67)	2 (33)	0 (0)	NS	4 (67)	2 (33)	0 (0)	0 (0)	0 (0)	NS
Distal/rectum	48	21 (44)	21 (44)	6 (12)		23 (48)	15 (31)	10 (21)		15 (31)	6 (13)	3 (6)	10 (21)	14 (29)
Tumor grade
Poor	8	5 (62)	3 (38)	0 (0)	NS	5 (63)	2 (25)	1 (12)	NS	4 (50)	1 (13)	0 (0)	1 (13)	2 (25)	NS
Moderate	44	19 (43)	19 (43)	6 (14)		21 (48)	15 (34)	8 (18)		14 (32)	7 (16)	3 (7)	8 (18)	12 (27)
Well	2	1 (50)	1 (50)	0 (0)		1 (50)	0 (0)	1 (50)		1 (50)	0 (0)	0 (0)	1 (50)	0 (0)	NS
Tumor stage
I-II	20	9 (45)	9 (45)	2 (10)	NS	8 (40)	10 (50)	2 (10)	NS	7 (35)	6 (30)	0 (0)	4 (20)	3 (15)	NS
III-IV	34	16 (47)	14 (41)	4 (12)		19 (56)	7 (21)	8 (23)		12 (35)	2 (6)	3 (9)	6 (18)	11(32)

MSI-H: Microsatellite instability-high; MSI-L: Microsatellite instability-low; MSS: Microsatellite stable; NS: Not significant; In paired normal/tumor tissues: H/H: Microsatellite instability-high/microsatellite instability-high; L/L: Microsatellite instability-low/microsatellite instability-low; S/S: Microsatellite stable/microsatellite stable; L/S: Microsatellite instability-low/microsatellite stable; S/L: Microsatellite stable/microsatellite instability-low; L/H: Microsatellite instability-low/microsatellite instability-high; H/L: Microsatellite instability-high/microsatellite instability-low.

Table 3 Correlation of hMLH1 methylation and microsatellite instability status of paired samples

		hMLH1 methylation (%)
		M/M	M/U	U/M	U/U	Total	P value
MSI status	H/H	1 (5)	5 (26)	0 (0)	13 (68)	19	NS
	L/L	1 (13)	4 (50)	0 (0)	3 (37)	8
	S/S	0 (0)	1 (33)	0 (0)	2 (67)	3
	L/S or S/L	1 (10)	3 (30)	0 (0)	6 (60)	10
	L/H or H/L	1 (7)	2 (14)	1 (7)	10 (71)	14
	Total	4 (7)	15 (28)	1 (2)	34 (63)	54

MSI: Microsatellite instability; M: Methylated; U: Unmethylated; In paired normal/tumor tissues: M/M: Methylated/methylated; U/U: Unmethylated/unmethylated; M/U: Methylated/unmethylated; U/M: Unmethylated/methylated; In paired normal/tumor tissues: H/H: Microsatellite instability-high/microsatellite instability-high; L/L: Microsatellite instability-low/microsatellite instability-low; S/S: Microsatellite stable/microsatellite stable; L/S: Microsatellite instability-low/microsatellite stable; S/L: Microsatellite stable/microsatellite instability-low; L/H: Microsatellite instability-low/microsatellite instability-high; H/L: Microsatellite instability-high/microsatellite instability-low; NS: Not significant.