Detecting Method And Clinical Value Of Circulating Tumor Cells In Gastrointestinal Stromal Tumors

Background: Circulating tumor cells(CTC)are prognostic and predictive for several cancer types.Only limited data exist regarding prognostic or predictive impact of CTC on gastrointestinal stromal tumor(GIST)patients.The aim of our study was to elucidate the prognostic and predictive role of CTC,and evaluate the efficacy of imatinib treatment in GIST patients.Methods: Taking the specific marker DOG1 in gastrointestinal stromal tumor as target gene.Extracting mononuclear cells from peripheral blood in 2 hours,and then extract RNA from PBMC and synthesis of cDNA.The expression levels of DOG1 were determined using quantitative real-time polymerase chain reaction(qRTPCR).The highest level of DOG1 expression in non-GIST samples was used as the “cutoff” value.Results: A total of 121 GIST patients and 54 non-GIST samples were enrolled in the study.The cutoff value for DOG1 positive was 3*10-5 and 65(54%)GIST patients were defined as DOG1 positive.DOG1 s were more frequently detected in unresectable patients.Tumor size,mitotic count and risk level were associated with DOG1 detection in resectable GIST patients.The presence of DOG1 significantly correlated with poor disease-free survival(15.3 versus 19.6 months,p = 0.038).Most patients turned DOG1-negative after surgery,and inversely the patients with consistently positive DOG1 had liver metastasis after surgery.All 21 patients with recurrence turned DOG1-positive with high DOG1 expression levels.Moreover,in the neoadjuvant setting,decline of DOG1 expression level correlated with the response of imatinib.Conclusion: DOG1 detection by qRT-PCR in peripheral blood is of clinical potential for monitoring recurrence and evaluating therapeutic efficacy of imatinib for GIST patients.