Approach to early-onset colorectal cancer: Clinicopathological, familial, molecular and immunohistochemical characteristics

Table 4 Comparison of the immunohistochemical analyses of microsatellite stable and microsatellite instability groups n (%)

	IHC expression				P
	MSS		MSI
	Normal	Lack	Normal	Lack
MMR system proteins
Mlh1	20 (100)	0 (0)	4 (50)	4 (50)	0.010
Msh2	21 (100)	0 (0)	3 (43)	4 (57)	0.002
Ms6	21 (100)	0 (0)	2 (40)	3 (60)	0.004
Apoptosis
Bcl-2	5 (24)	16 (76)	2 (29)	5 (71)	NS
Cell adhesion
β-catenin
Membrane	18 (86)	3 (14)	6 (86)	1 (14)	NS
Nucleus	8 (38)	13 (62)	2 (29)	5 (71)	NS
E-cadherin	15 (75)	5 (25)	4 (60)	2 (40)	NS
Cell cycle markers
Chk2	10 (53)	9 (47)	4 (60)	2 (40)	NS
Cyclin A	8 (38)	13 (62)	5 (71)	2 (29)	NS
Cyclin D1	7 (33)	14 (67)	5 (71)	2 (29)	NS
Cyclin D3	8 (38)	13 (62)	4 (57)	3 (43)	NS
Cyclin E	3 (14)	18 (86)	5 (83)	1 (17)	0.004
p16	9 (43)	12 (57)	4 (67)	2 (33)	NS
p21	10 (53)	9 (47)	4 (67)	2 (33)	NS
p27	8 (44)	10 (56)	4 (80)	1 (20)	NS
RB-P	11 (55)	9 (45)	2 (29)	5 (71)	NS
Skp2	9 (43)	12 (57)	3 (60)	2 (40)	NS
Cdk2	9 (43)	12 (57)	4 (67)	2 (33)	NS
Proliferation
p53	11 (52)	10 (48)	5 (57)	3 (43)	NS
Ki-67	14 (67)	7 (33)	3 (50)	3 (50)	NS
Others
CK20	9 (75)	3 (25)	1 (20)	4 (80)	NS
RAD50	9 (75)	3 (25)	1 (25)	3 (75)	NS
SMAD4	11 (55)	9 (45)	2 (50)	2 (50)	NS

IHC: Immunohistochemical; MSS: Microsatellite stable; MSI: Microsatellite instability; MMR: Mismatch repair; NS: Not significant.