Abstract 2229: Detection of somatic mutations in KRAS gene in Chilean patients with advanced colorectal cancer

Abstract

Abstract Introduction: At present, the application of tailored oncologic therapies requires previous performance of mutational analysis of certain genes. In patients with advanced colorectal cancer (CRC), it is essential to detect the presence of activating mutations in the KRAS gene to predict the effectiveness of certain treatments. Purpose: To determine the presence of KRAS mutations in Chilean patients with advanced CRC, and correlate the mutational status with clinical-pathological data. Methods: Between October 2009 and August 2010, we prospectively studied the presence of somatic mutations in the KRAS gene in codons 12 and 13 in biopsies of patients with advanced colorectal cancer by allele specific and real time PCR kit. The results were registered in a database, along with the pathology results and clinical data of the patients. Statistical analysis was performed by Student T test and Chi-square test. A p>0.05 was no significant. Results: A total of 123 patients were analyzed, with a mean age of 61 years and male predominance (60%). Mutations were detected in 47 (39%) of them and only in 2 cases the study was inconclusive. The distribution of the different mutations was as follows: 12Asp (32%), 12Val (26%), 13Asp (19%), 12Cys (11%), 12Ala (6%) and 12Ser (6%). Separated by gender, the detection rate was higher in male patients (45% vs 30%) (p=0.59). Analyzing the data by location of tumor, we found that mutations in right colon tumors was present in 26% (6/23), whereas tumors of the left colon and sigmoid were 43% (16/37) (p=0.1). Mutations detected in patients with lymph node metastasis was 42% comparing to node-negative patients (32%) (p=0.3). In patients with poorly differentiated tumors we found 50% mutations compared to well differentiated (18%) (p=0.08). Finally, the mortality was similar when we compared between WT and mutations patients. Conclusions: In Chile, 39% of patients with advanced CRC carry mutations in KRAS gene. This result is similar to that described in other populations. There is a tendency to a higher mutation rate in males, patients with left colon cancer, poorly differentiated tumors and patients with lymph nodal involvement. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2229. doi:10.1158/1538-7445.AM2011-2229