Table 1

Relationship between p21, EGFR expression and clinicopathological characteristics of colorectal cancer

Clinicopathological characteristics	p21 expression			P value	EGFR expression			P value
Clinicopathological characteristics	–	+	++	P value	–	+	++	P value
Age (years)				0.666				0.502
<50	830	203	1441		578	294	543
≥50	3274	863	5698		2490	1354	2514
Gender				0.448				0.184
Female	1647	407	2869		1224	617	1222
Male	2457	659	4270		1844	1031	1835
Primary tumour site				<0.001*				0.479
Rectum	2250	499	3792		1640	852	1585
Distal	904	200	1665		695	390	685
Proximal	929	192	1669		677	376	740
Synchronous	12	175	0		52	27	44
Mucinous subtype				<0.001*				<0.001*
Negative	2777	745	5501		2203	1078	1856
Positive	390	79	569		236	101	83
Tumour differentiation				0.107				0.001*
Poor	50	14	101		44	21	33
Moderate	2877	751	5133		2186	1176	2075
Well	1043	288	1692		750	418	889
Lymphovascular invasion				0.025*				<0.001*
Negative	2853	757	5149		2277	1170	2103
Positive	1192	306	1915		785	477	947
Perineural invasion				<0.001*				<0.001*
Negative	2920	755	5373		2314	1185	2095
Positive	1130	311	1707		751	461	956
Circumferential resection margin				0.045*				0.053
Negative	3615	1020	6656		2971	1588	2876
Positive	85	17	110		35	20	55
Tumour size (cm)				0.215				0.005*
<4	2879	733	4900		2165	1167	2053
≥4	1206	330	2209		892	479	995
T stage				<0.001*				<0.001*
Tis	16	5	26		14	8	10
T1	152	48	296		150	71	102
T2	677	181	1204		530	266	463
T3	940	499	2649		1116	903	2031
T4	2307	331	2946		1251	399	440
N stage				0.002*				0.014*
N0	1929	545	3634		1623	825	1491
N1	1347	332	2201		937	539	986
N2	826	189	1303		508	284	579
M stage				0.522				0.441
M0	3550	933	6222		2661	1408	2629
M1	554	133	917		407	240	428
TNM stage				0.021*				0.045*
0	13	4	21		13	7	6
I	595	166	1117		497	241	418
II	1192	334	2277		1001	524	959
III	1747	429	2796		1147	635	1241
IV	554	133	917		407	240	428
Mismatch repair				<0.001*				0.609
pMMR	3087	956	6159		2824	1522	2806
dMMR	895	103	892		225	114	236
Microsatellite instability				0.402				0.197
MSS	37	15	94		46	29	41
MSI-H	5	1	8		2	6	3
MSI-L	1	2	3		1	1	3
KRAS				0.639				0.449
Wild type	443	194	627		345	267	499
Mutant type	382	148	520		277	214	448
NRAS				0.595				0.95
Wild type	684	326	997		549	469	911
Mutant type	23	10	25		17	13	26
BRAF				0.166				0.004*
Wild type	729	326	996		568	463	882
Mutant type	23	12	50		10	17	47

– represents negative, + represents weakly positive, ++ represents positive.
*P<0.05.
dMMR, deficient mismatch repair; MSI-H, high microsatellite instability; MSI-L, low microsatellite instability; MSS, microsatellite stability; pMMR, proficient mismatch repair; TNM, tumour, node, metastases.