Clinical trials

Gastrointestinal stromal tumors (GISTs) are mostly driven by c-kit or PDGFRA mutations, and commonly occur in the stomach and small intestine. Targeted therapy is the mainstay for advanced metastatic GISTs, but there is a lack of effective regimens after drug resistance. Immune checkpoint inhibitors (ICIs) have limited efficacy as monotherapy, while tyrosine kinase inhibitor (TKI) drugs such as regorafenib can improve the immune microenvironment and exert a synergistic effect when combined with ICIs, with more significant efficacy especially in cases with kit exon 17 mutations. This study aims to explore the effectiveness of regorafenib combined with envafolimab in metastatic gastrointestinal stromal tumors with kit exon 17 mutations that have failed standard treatment.

iMS-LC Assay (intact M-protein Screening-Light Chain Assay) is a new technology based on mass spectrometry identification of intact clonal immunoglobulin light chains for the specific detection of M-proteins in peripheral blood. The investigators propose to conduct a prospective, single-center observational study to screen for M-proteins in the peripheral blood of individuals undergoing routine physical examinations using iMS-LC Assay technology. The goals of this observational study are : (1) to evaluate the diagnostic efficacy of detecting peripheral blood M-proteins using the iMS-LC Assay method; and (2) to determine the prevalence of MGUS in the population undergoing routine physical examinations based on mass spectrometry screening. Initially, the investigators will collect clinical patient samples continuously and conduct a diagnostic trial of the iMS-LC Assay, using the clinical methods SPEP + SIFE + FLC as the gold standard. Based on the diagnostic performance of the iMS-LC Assay, the investigators will then screen for M-proteins in continuous samples from individuals undergoing routine physical examinations, to further determine the prevalence of MGUS in this population based on mass spectrometry screening.