Role of detection of microsatellite instability in Chinese with hereditary nonpolyposis colorectal cancer or ordinary hereditary colorectal cancer

Table 1 Primer sequence of MSI and annealing temperature

Locus	Primer sequence	Annealingtemperature (°C)
BAT26	TGACTACTTTTGACTTCAGCC	53.9
	AACCATTCAACATTTTTAACCC
BAT25	TCGCCTCCAAGAATGTAAGT	53.4
	TCTGCATTTTAACTATGGCTC
D2S123	AAACAGGATGCCTGCCTTTA	57.4
	GGACTTTCCACCTATGGGAC
D5S346	ACTCACTCTAGTGATAAATCGGG	54.0
	AGCAGATAAGACAGTATTACTAGTT
D17S250	GGAAGAATCAAATAGACAAT	53.6
	GCTGGCCATATATATATTTAAACC

Table 2 Detection of MSI in three groups (%)

Group	n	MSI-H	MSI-L	MSS
A	20	85 (17/20)	10 (2/20)	5 (1/20)
B	20	40 (8/20)	35 (7/20)	25 (5/20)
C	20	10 (2/20)	30 (6/20)	60 (12/20)

MSI-H: high frequency microsatellite instability; MSI-L: low frequency microsatellite instability; MSS: microsatellite stable.

Table 3 Relationship among MSI-H, mean age of the patients and the sites of cancer (%)

Group	n	MSI-H	Mean age (yr)	Right hemicolon	Left hemicolon
A	20	17 (85)	43.6	11 (64.7)	6 (35.3)
B	20	8 (40)	52.2	5 (62.5)	3 (37.5)
C	20	2 (10)	61.8	0 (0)	2 (100)

Table 4 Ratio of every locus occupying in the MSI-H (%)

Locus	Positive ratio of MSI-H	Positive ratio of MSI
BAT26	94.1 (16/17)	85 (17/20)
BAT25	94.1 (16/17)	90 (18/20)
D2S123	64.7 (11/17)	55 (11/20)
D5S346	52.9 (9/17)	50 (10/20)
D17S250	35.3 (6/17)	40 (8/20)