Mutations in epidermal growth factor receptor and K-ras in Chinese patients with colorectal cancer.
BACKGROUND
Mutations of EGFR and K-ras are biomarkers for predicting the efficacy of targeting agents in non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). Data on the gene mutation status of EGFR and K-ras in Chinese patients with CRC are limited.


METHODS
EGFR mutations in exon 18-21 and K-ras mutations in exon 1 and 2 were detected in tumor samples from 101 Chinese patients with CRC by polymerase chain reaction and Sanger sequencing. [corrected] The relationship between patients' characteristics and survival time and gene mutation status were analyzed using the Statistical Package for the Social Sciences.


RESULTS
Only two samples (2.0%) had EGFR mutations in exon 18 or 21, and 33 of 101 samples (32.7%) had K-ras mutations in codon 12, 13, 45, 69, or 80. Univariate analysis suggested that differentiation might be correlated with K-ras mutations (p = 0.05), which was confirmed by a logistic regression model (p = 0.04). The median overall survival (OS) and median survival after metastasis were 44.0 and 18.0 months, respectively, in the mutant K-ras group, and 53.3 and 19.0 months, respectively, in the wild K-ras group. K-ras mutation was not an independent prognostic factor for OS or survival after metastasis (p = 0.79 and 0.78, respectively).


CONCLUSIONS
In Chinese patients with CRC, EGFR mutations were rare, and K-ras mutations were similar to those of Europeans. New mutations in codons 45, 69, and 80 were found in the Chinese population. Poor differentiation was an independent factor related to K-ras mutations.
Yunxia
Zuo
Z
Department of Medical Oncology, Fudan University Cancer Hospital, Shanghai Medical School, Shanghai 200032, PR China.
Jun
Cao
C
Guanshan
Zhu
Z
Yachao
Lu
L
Xueke
Zhou
Z
Jin
Li
L
D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D002681:China; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D005260:Female; D018773:Genes, erbB-1 / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation; D016019:Survival Analysis