A specific region of the small bowel, called the duodenal-jejunal flexure, shows a high frequency of gastrointestinal stromal tumors with mutations of the NF1 gene, according to researchers at UC San Diego Moores Cancer Center, Memorial Sloan Kettering Cancer Center and Fox Chase Cancer Center. The small bowel, where approximately 30 percent of all GISTs occur, is divided into three anatomically, histologically and functionally distinct segments: the duodenum, jejunum and ileum. Most small bowel GISTs are associated with KIT mutations. However, a subset of GISTs have mutations in other genes, such as NF1.“Where the duodenum transitions into the jejunum, we are finding an over-representation of NF1-mutated GIST,” said Jason Sicklick, a surgical oncologist at Moores Cancer Center.NF1 can be mutated both somatically (within tumor DNA) or in the germline (part of the hereditary condition called Neurofibromatosis type I). Patients with NF-1 are 34 times more likely to develop GIST than unaffected individuals.
New research led by Friends of Cancer Research demonstrates that decreases in circulating tumor DNA after initiation of treatment are associated with improved overall survival in patients with advanced non-small cell lung cancer treated with immunotherapy or chemotherapy.
