Next-generation sequencing of esophageal carcinosarcoma to reveal high frequency of actionable PIK3CA gene mutations.

Abstract

e15503 Background: Esophageal carcinosarcoma (ESC) is a rare malignant esophageal neoplasm consisting of both carcinomatous and sarcomatous components. Drive genes mutations may potentially serve as novel biomarkers to targeted therapy in ESC, and they also may explain the mechanisms of the unique dual-differentiation pattern. Actionable gene alterations with any significant frequency in ESC were unknown due to specimen numbers and limited studies. A comprehensive study of clinical characteristic and molecular alterations in ESC is needed to better understand biology and guide therapy. Methods: Fifteen cases of ESCs which received surgical resection were retrospectively collected from the Zhejiang Cancer Hospital in China between 2009 and 2016, next generation sequencing was performed to identify genotypic changes, and clinical characteristic of these patients was also collected and analyzed. Results: ESC patients are easily occurred in male, heavy smokers, and old patients. The mainly gross types were medullary and fungating type. Mutation of phosphatase and tensin homologue ( PTEN), MAP2K1(MEK1), anaplastic lymphoma kinase ( ALK), RET, and NF1 were detected in one patient respectively. Mutation of ERBB2(HER2), MET and single copy loss of Rb1 were detected in two patients respectively. Mutation of ROS1 and phosphoinositide-3-kinase catalytic alpha ( PIK3CA) were detected in three patients respectively. Conclusions:PIK/AKT pathway may be important in pathogenesis of ESCs, and it may be an ideal therapeutic target.