CTLs/regulatory T-cells ratio as a prediction marker of chemotherapy in metastatic colorectal cancer.

Abstract

e14684 Background: Many multiple anti cancer drugs regimens have been established for metastaticcolorectal cancer recently. We investigated cellular immunoreaction of these patients to their cancer. Methods: 32 metastatic colorectal cancer patients have been started chemotherapies. Their PBMCs were harvested and investigated their character by Fac scan with fluorescent labeled antibodies (CD3,CD8, CD4, CD25, Foxp3) at before and after chemotherapy. Results: After chemotherapy, both CTLs(CD3, CD8 positive) and regulatory T cells (CD4, CD25, Foxp3 positive) were decreased in number among all patients. On the other hand, CTL/T reg ratio were significantly increased among tumor marker decreased patients and significantly decreased among tumor marker increased or stable patients. CEA levels among 85.7% of increased CTL/T reg ratio patients became to decrease less thanhalf. CEA levels among 66.7% of decreased CTL/T reg ratio patients became to increase or to be stable, if their regimens have not been changed. The Reactive Rate of chemotherapy of CTL/T reg ratio increased patients was significantly higher than that of ratio decreased or stable patients. (P=0.021) The Disease Control Rate of chemotherapy of CTL/T reg ratio increased patients was higher than that of ratio decreased patients. Both resectability rate of liver metastatic lesion and early tumor shrinkage rate were higher at the CTL/T reg ratio increased patients group than at the other patients group. Conclusions: We found that the CTL/T reg ratios of PBMC in metastatic colorectal cancer patients were useful for prediction of the effect of chemotherapy.