To improve the understanding of CD117-negative gastrointestinal stromal tumor / 中华胃肠外科杂志

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the digestive tract. The diagnosis of GIST relies mainly on clinicopathological features, tumor cell morphology and immunohistochemical marker CD117 (c-Kit). However, some tumors (about 3%-4%) have clinicopathological features of GIST but do not express CD117. To determine whether these lesions are true GIST, it is necessary to raise awareness of CD117-negative GIST. This article discusses the immunohistochemical features, gene mutations, prognosis and efficacy of targeted drugs of CD117-negative GIST. Research results suggest that CD117-negative GIST lacks KIT expression but has typical clinical, histopathological and cytogenetic features. These tumors have KIT and/or PDGFRA mutations, or are wild type. Because most KIT-negative GISTs contain PDGFRA or KIT mutation, pathologists and oncologists should not exclude GIST diagnosis based on negative immunohistochemical staining of KIT. It is known that approximately 30% of PDGFRA mutations may be sensitive to imatinib, and patients with such tumors may benefit from imatinib, so imatinib treatment should not be empirically denied in these patients.

The clinical observation of relapsed or refractory acute myeloid leukemia in patients with high CD117 expression but no FLT3-ITD mutation treated with sorafenib alone / 天津医药

@#Objective To make a primary investigation of outcomes in relapsed or refractory (R/R) acute myeloid leukemia (AML) patients who were FLT3-ITD mutation negative and treated with sorafinib alone. Methods The clinical responses and survival of R/R AML patients who underwent sorafenib treatment only were retrospectively analyzed. The side effects and response results were assessed according to common terminology criteria for adverse events (CTCAE) v 4.0 from US National Institutes of Health and NCCN guideline. Results Four out of seven patients achieved complete remission by sorafenib treatment alone. The median time required for remission was 36 days in the four patients. Among them, only 1 patient stopped the maintenance treatment because of side effect of serious skin lesion. Three patients showed no response to sorafenib, including 2 accepted stem cell transplantation and 1 retrieved to salvage chemotherapy. All of them achieved complete remission later. One patient developed grade 1 adverse event of liver. Another one developed grade 3 skin lesion. All patients experienced neutropenia of more than 7 days without unendurable infections and early deaths. The median follow-up time for the whole cohort was more than 22 months. Three patients passed away for relapse of AML and their disease-free survival time with sorafenib ranged from 2 to 20 months. All four patients accepted stem cell transplantation were still surviving no matter whether or not they were responsive to sorafinib before. The median survival time for these seven patients was 650 days. Conclusion The R/R AML patients with negative FLT3-ITD mutation and high expression of CD117 treated with sorafenib alone have good remission and long term survival.