Comprehensive analysis of gene mutations and mismatch repair in Chinese colorectal cancer patients

Table 1 Clinicopathological characteristics of patients cohort, n (%)

Characteristics	All cases (n = 2271)	Characteristics	All cases (n = 2271)
Sex		Perineural invasion
Male	1361 (59.9)	No	1484 (65.3)
Female	910 (40.1)	Yes	786 (34.6)
Age category (yr)		NA	1 (< 0.01)
≤ 50	288 (12.7)	Vascular invasion
> 50	1983 (87.3)	No	1779 (78.3)
Smoking status		Yes	486 (21.4)
No	1762 (77.6)	NA	6 (0.3)
Yes	509 (22.4)	Histological type
Drinking status		Adenocarcinoma	2250 (99.1)
No	1848 (81.4)	Mucinous adenocarcinoma	113 (5.0)
Yes	423 (18.6)	Others	21 (0.9)
Family history		Histological differentiation grade
No	1971 (86.8)	Poorly differentiated	226 (10.0)
Yes	300 (13.2)	Moderately/well differentiated	1878 (82.7)
Tumor location		NA	167 (7.4)
Right colon	551 (24.3)	Stage
Left colon	1718 (75.6)	Tis	18 (0.8)
Liver	2 (0.1)	I	304 (13.4)
Cancer nodules		II	836 (36.8)
No	1782 (78.5)	III	935 (41.2)
Yes	489 (21.5)	IV	178 (7.8)

Tis: Carcinoma in situ. NA: Not available.

Table 2 Distribution of KRAS, NRAS, PIK3CA, and BRAF mutations in patients with colorectal carcinoma, n (%)

Mutation genes	All patients (n = 2271)	Mucinous adenocarcinoma (n = 113)
KRAS
Exon 2	653 (28.8)	42 (37.2)
Exon 3	34 (1.5)	3 (2.7)
Exon 4	48 (2.1)	5 (4.4)
Exon 2/3	3 (0.1)	0
Exon 2/4	3 (0.1)	0
NRAS
Exon 2	33 (1.5)	0
Exon 3	25 (1.1)	0
BRAF
Exon 15	85 (3.7)	14 (12.4)
PIK3CA
Exon 20	88 (3.9)	8 (7.1)

Table 3 Comparison of mismatch repair immunohistochemistry and microsatellite instability testing, n (%)

Test results of MSI	MMR IHC normal (n = 2092)	MMR IHC abnormal (n = 179)
MSS	2079 (99.4)	6 (3.4)
MSI-L	5 (0.2)	2 (1.1)
MSI-H	8 (0.4)	171 (95.5)

MSI: Microsatellite instability; MSI-H: Microsatellite instability-high; MSI-L: Microsatellite instability-low; MSS: Microsatellite-stable; MMR: Mismatch repair; IHC: Immunohistochemistry.