Small-bowel adenocarcinoma (SBA) is a rare cancer that is frequently diagnosed at later stages and have poorer overall survival rate than other gastrointestinal tract related cancers. The molecular features of SBA is lacking due to the lack of comprehensive genomic analysis. Recently, researchers used hybrid capture-based genomic profiling to compare the differences in molecular features among SBA, colorectal cancer (CRC) and gastric cancer patients. The results showed that SBA bears mutations distinct from CRC and gastric cancers. For instance, mutation rates of APC is 26.8 % in SBA compared with 75.9 % in CRC and 7.8% in gastric cancer. Moreover, though BRAF mutations are detected in both SBA and CRC, the mutation rate of BRAF V600E tends to be lower in SBA. In addition, SBA also has distinct molecular features, including high degree of microsatellite instability (MSI), high tumor mutation burden and several actionable genes like PIK3CA, ERBB2, and BRAF mutations. These findings indicate that these distinct molecular profiles of SBA could guide further immunotherapy treatment and targeted therapy development in the future.
2. Publication：JAMA Oncol. 2017 Jun 15