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Open Access Highly Accessed Research article

Mutations in epidermal growth factor receptor and K-ras in Chinese patients with colorectal cancer

Zuo Yunxia1, Cao Jun1, Zhu Guanshan2, Lu Yachao2, Zhou Xueke1 and Li Jin1*

Author Affiliations

1 Department of Medical Oncology, Fudan University Cancer Hospital, Shanghai Medical School, Shanghai 200032, PR China

2 Innovation Center China, AstraZeneca Global R&D, 898 Halei Road, Shanghai 201203, PR China

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BMC Medical Genetics 2010, 11:34  doi:10.1186/1471-2350-11-34

Published: 26 February 2010

Abstract

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-single strand conformational polymorphism. 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.