Molecular Testing for Gastrointestinal Cancer

• Published in: Journal of pathology and translational medicine Vol. 51; no. 2; pp. 103 - 121
• Main Authors: Lee, Hye Seung, Kim, Woo Ho, Kwak, Yoonjin, Koh, Jiwon, Bae, Jeong Mo, Kim, Kyoung-Mee, Chang, Mee Soo, Han, Hye Seung, Kim, Joon Mee, Kim, Hwal Woong, Chang, Hee Kyung, Choi, Young Hee, Park, Ji Y, Gu, Mi Jin, Lhee, Min Jin, Kim, Jung Yeon, Kim, Hee Sung, Cho, Mee-Yon
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Society of Pathologists, Korean Society for Cytopathology 01.03.2017; The Korean Society of Pathologists and the Korean Society for Cytopathology; Korean Society of Pathologists & the Korean Society for Cytopathology; 대한병리학회
• Subjects: Colorectal cancer; Colorectal neoplasms; Deoxyribonucleic acid; DNA; Epidermal growth factor; Esophagus; Gastric cancer; Gastric neoplasms; Genes; Genomes; Genomics; Histology; Medical screening; Metastasis; Molecular biology; Molecular diagnosis; Mutation; Prognosis; Review; Targeted therapy; Tumors; 병리학; Gastric neoplasms; Molecular diagnosis; Prognosis; Colorectal neoplasms; Targeted therapy
• ISSN: 2383-7837; 2383-7845
• DOI: 10.4132/jptm.2017.01.24

With recent advances in molecular diagnostic methods and targeted cancer therapies, several molecular tests have been recommended for gastric cancer (GC) and colorectal cancer (CRC). Microsatellite instability analysis of gastrointestinal cancers is performed to screen for Lynch syndrome, predict favorable prognosis, and screen patients for immunotherapy. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor has been approved in metastatic CRCs with wildtype ( and exon 2-4). A mutation is required for predicting poor prognosis. Additionally, amplification of human epidermal growth factor receptor 2 ( ) and is also associated with resistance to EGFR inhibitor in metastatic CRC patients. The V600E mutation is found in sporadic microsatellite unstable CRCs, and thus is helpful for ruling out Lynch syndrome. In addition, the mutation is a prognostic biomarker and the mutation is a molecular biomarker predicting response to phosphoinositide 3-kinase/AKT/mammalian target of rapamycin inhibitors and response to aspirin therapy in CRC patients. Additionally, HER2 testing should be performed in all recurrent or metastatic GCs. If the results of HER2 immunohistochemistry are equivocal, silver or fluorescence hybridization testing are essential for confirmative determination of HER2 status. Epstein-Barr virus-positive GCs have distinct characteristics, including heavy lymphoid stroma, hypermethylation phenotype, and high expression of immune modulators. Recent advances in next-generation sequencing technologies enable us to examine various genetic alterations using a single test. Pathologists play a crucial role in ensuring reliable molecular testing and they should also take an integral role between molecular laboratories and clinicians.