Molecular Profiling of Colorectal Cancer
Colorectal cancer is the second leading cause of cancer related mortality in the United States, with an estimated 140,250 new cases and 50,630 deaths anticipated in 2018 (ACS 2018). With the advent of more chemotherapy options and with the availability of biologic therapies in the recent past, mortality rates are declining, and patients are living longer. Over the past 20 years, survival in metastatic colorectal cancer has more than doubled. Nonetheless, colorectal cancer remains the second leading cause of cancer related death in the United States. New therapeutic strategies are clearly needed.
The main histologic subtype of colorectal cancer is adenocarcinoma. Colorectal adenocarcinomas arise through the acquisition of a series of mutations that occur over the space of many years, and results in the evolution of normal epithelium to adenoma to carcinoma to metastasis (Fearon and Vogelstein 1990). In the past two decades, there has been increasing recognition that some somatic mutations may be prognostic or predictive markers for specific therapies available in colorectal cancer. These mutations involve genes such as KRAS, BRAF, PIK3CA, AKT1, SMAD4, PTEN, NRAS, and TGFBR2 (Baba et al. 2011; De Roock et al. 2010; Dienstmann et al. 2011; Fernandez-Peralta et al. 2005; Haigis et al. 2008; Negri et al. 2010; Papageorgis et al. 2011; Sartore-Bianchi et al. 2009). Furthermore, there has been increasing recognition that some of these mutant gene products may be targets for drug development. (De Roock et al. 2010; Huang et al. 2008; Thenappan et al. 2009).
The following text is meant to provide a broad overview of several of the oncogenes known to be important for colorectal cancer pathogenesis. Where possible, the presence of a specific mutation is correlated to clinical parameters as well as response to both conventional chemotherapy and targeted agents. At present, unless otherwise noted, only data for the treatment of stage IV disease is presented.
Suggested Citation: Chan, E. 2018. Molecular Profiling of Colorectal Cancer. My Cancer Genome https://www.mycancergenome.org/content/disease/colorectal-cancer/ (Updated March 16).
Last Updated: March 16, 2018