title: Comparison of KRAS/BRAF mutations between primary tumors and serum in colorectal cancer: Biological and clinical implications.
abstract: In colorectal cancer (CRC), KRAS and BRAF mutations in primary tumors are associated with resistance to anti-epidermal growth factor receptor (anti-EGFR)-based therapies. However, the correlation between KRAS/BRAF mutation in primary tumors and serum has not been well studied. To evaluate the degree of concordance of KRAS/BRAF mutations between the primary tumors and the matched serum samples in CRC, serum and tumor tissues were collected from 115 patients with CRC and KRAS/BRAF mutations were examined by nested polymerase chain reaction (PCR) and direct sequencing. BRAF mutations were present in 3.5% (4/115) of the primary tumor tissue samples and 0.87% (1/115) of the serum samples. In the 4 primary tumors with BRAF mutations, identical mutations were not observed in the corresponding serum samples (κ=-0.016). KRAS mutations were observed in 32.2% (37/115) of the primary tumors and 11.3% (13/115) of the serum samples. Of the 37 tumor cases with KRAS mutations, 9 had identical mutations in the corresponding serum sample, with a concordance rate of 24.3% (9/37). Discordance was observed in 32 (27.8%) patients. The concordance between KRAS mutations in the primary tumors and KRAS mutations in the matched serums was low (κ=0.231). The results of the present study suggest that the possibility of differences in the mutational status of KRAS/BRAF between primary tumors and matched serum samples should be considered when patients are selected for anti-EGFR-based therapies.
authors.affiliation: Department of Medical Oncology, Cancer Center, Sun Yat-sen University, Guangzhou 510060;
authors.forename: Xingxiang
authors.initials: X
authors.lastname: Pu
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Pan
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.forename: Ying
authors.initials: Y
authors.lastname: Tian
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Guo
authors.forename: Lin
authors.initials: L
authors.lastname: Wu
authors.forename: Xuexing
authors.initials: X
authors.lastname: He
authors.forename: Xinggui
authors.initials: X
authors.lastname: Chen
authors.forename: Shaodan
authors.initials: S
authors.lastname: Zhang
authors.forename: Tongyu
authors.initials: T
authors.lastname: Lin