Abstract
The molecular genetics of colorectal cancers (CRCs) is among the best understood of common human cancers. It is difficult to predict the prognosis and/or to predict chemoresponding in CRC patients. At present, prognosis is based predominantly on the tumor stage and pathological examination of the disease. Molecular classification of CRCs, based on genomics and transcriptomics, proposed that CRCs can be classified into at least three-to-six subtypes, depending on the gene expression pattern, and groups of marker genes representing to each subtype have also been reported. Gene expression-based subtyping is now widely accepted as a relevant source of disease stratification. We reviewed the previous studies on CRC subtyping, international consortium dedicated to large-scale data sharing and analytics recently established four consensus molecular subtypes with distinguishing features. Predictive markers identified in these studies are under investigation and large-scale clinical evaluations of molecular markers are currently in progress.
References
1. Aust DE. WHO classification 2010 for the lower gastrointestinal tract: what is new? Pathologe. 2011; 32(Suppl 2):326–331.
2. Fleming M, Ravula S, Tatishchev SF, Wang HL. Colorectal carcinoma: Pathologic aspects. J Gastrointest Oncol. 2012; 3:153–173.
3. Ogino S, Goel A. Molecular classification and correlates in colorectal cancer. J Mol Diagn. 2008; 10:13–27.
4. Rajagopalan. Nowak MA, Vogelstein B, Lengauer C. The significance of unstable chromosomes in colorectal cancer. Nat Rev Cancer. 2003; 3:695–701.
7. Pino MS, Chung DC. The chromosomal instability pathway in colon cancer. Gastroenterology. 2010; 138:2059–2072.
8. Boland CR, Goel A. Microsatellite instability in colorectal cancer. Gastroenterology. 2010; 138:2073–2087.e3.
10. Kim WK, Park M, Park M, et al. Identification and selective degradation of neopeptide-containing truncated mutant proteins in the tumors with high microsatellite instability. Clin Cancer Res. 2013; 19:3369–3382.
11. Kim H, Jen J, Vogelstein B, Hamilton SR. Clinical and pathological characteristics of sporadic colorectal carcinomas with DNA replication errors in microsatellite sequences. Am J Pathol. 1994; 145:148–156.
12. Kloor M, Michel S, von Knebel Doeberitz M. Immune evasion of microsatellite unstable colorectal cancers. Int J Cancer. 2010; 127:1001–1010.
13. Cancer Genome Atlas Network. Comprehensive molecular characterization of human colon and rectal cancer. Nature. 2012; 487:330–337.
14. Walther A, Johnstone E, Swanton C, Midgley R, Tomlinson I, Kerr D. Genetic prognostic and predictive markers in colorectal cancer. Nat Rev Cancer. 2009; 9:489–499.
15. Wolpin BM, Mayer RJ. Systemic treatment of colorectal cancer. Gastroenterology. 2008; 134:1296–1310.
16. Budinska E, Popovici V, Tejpar S, et al. Gene expression patterns unveil a new level of molecular heterogeneity in colorectal cancer. J Pathol. 2013; 231:63–76.
17. Marisa L, de Reyniès A, Duval A, et al. Gene expression classification of colon cancer into molecular subtypes: characterization, validation, and prognostic value. PLoS Med. 2013; 10:e1001453.
18. Roepman P, Schlicker A, Tabernero J, et al. Colorectal cancer intrinsic subtypes predict chemotherapy benefit, deficient mismatch repair and epithelial-to-mesenchymal transition. Int J Cancer. 2014; 134:552–562.
19. De Sousa E Melo F, Wang X, Jansen M, et al. Poor-prognosis colon cancer is defined by a molecularly distinct subtype and develops from serrated precursor lesions. Nat Med. 2013; 19:614–618.
20. Sadanandam A, Lyssiotis CA, Homicsko K, et al. A colorectal cancer classification system that associates cellular phenotype and responses to therapy. Nat Med. 2013; 19:619–625.
21. Schlicker A, Beran G, Chresta CM, et al. Subtypes of primary colorectal tumors correlate with response to targeted treatment in colorectal cell lines. BMC Med Genomics. 2012; 5:66.
22. Guinney J, Dienstmann R, Wang X, et al. The consensus molecular subtypes of colorectal cancer. Nat Med. 2015; 21:1350–1356.
23. Warner GC, Reis PP, Makitie AA, et al. Current applications of microarrays in head and neck cancer research. Laryngoscope. 2004; 114:241–248.
24. Salazar R, Roepman P, Capella G, et al. Gene expression signature to improve prognosis prediction of stage II and III colorectal cancer. J Clin Oncol. 2011; 29:17–24.
25. Colombo PE, Milanezi F, Weigelt B, Reis-Filho JS. Microarrays in the 2010s: the contribution of microarray-based gene expression profiling to breast cancer classification, prognostication and prediction. Breast Cancer Res. 2011; 13:212.
26. Collisson EA, Sadanandam A, Olson P, et al. Subtypes of pancreatic ductal adenocarcinoma and their differing responses to therapy. Nat Med. 2011; 17:500–503.
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Table 2.
MSI, microsatellite instable; CIMP, CpG island methylator phenotype; SAR, survival after relapse; SCNA, somatic copy number alteration