Objective: To identify changes in peripheral immune responses in patients with metastatic colorectal cancer (mCRC) treated with irinotecan/5-fluorouracil/leucovorin (IFL) alone or in combination with cetuximab (C-IFL). Methods: Peripheral blood mononuclear cells (PBMCs) collected from healthy donors (n = 20) and patients with mCRC receiving treatment with either IFL (n = 30) or C-IFL (n = 30) were tested for cytokine production upon polyclonal stimulation with anti-CD3 monoclonal antibody, T cell proliferation in the autologous mixed lymphocyte reaction (auto-MLR) and T regulatory cell (Treg) frequency. The respective results were evaluated over two treatment cycles and further assessed in relation to response to treatment. Results: PBMCs prior to treatment exhibited significantly lower production of IL-2, IFN-γ, IL-12 and IL-18 cytokines and lower auto-MLR responses, whereas Treg frequency, IL-4, IL-10 cytokines were increased compared to healthy donors. During treatment, IL-2, IFN-γ, IL-12, IL-18 and auto-MLR responses increased, while Treg frequency and IL-10 secretion decreased significantly compared to the baseline. Responders to treatment exhibited a significantly higher increase in IL-2, IFN-γ, IL-12 and IL-18 production and auto-MLR responses, and higher decrease in IL-4, IL-10 secretion and Treg frequency. Among all patient subgroups analysed, responders to C-IFL demonstrated significantly higher increase in auto-MLR responses, IL-12 and IL-18 secretion and higher decrease in Treg frequency. Conclusion: The disturbed immune parameters observed in patients with mCRC at presentation can be significantly improved during treatment with IFL and this effect can be potentiated by the addition of cetuximab. Monitoring of the peripheral immune system function could be used as surrogate marker in predicting treatment-related outcome.

Our aim was to evaluate the predictive and prognostic influence of BRAF mutation and other molecular, clinical and laboratory parameters in stage IV colorectal cancer (CRC). 60 patients were included in this retrospective analysis, and 17 variables were examined for their relation with treatment response and survival. KRAS mutation was identified in 40.3 % of cases, BRAF and PIK3CA in 8.8 % and 10.5 % respectively. 29.8 % of patients responded to treatment. Median survival time was 14.3 months. Weight loss, fever, abdominal metastases, blood transfusion, hypoalbuminaimia, BRAF and PIK3CA mutations, CRP and DNA Index were associated with survival. In multivariate analysis, male patients had 3.8 times higher probability of response, increased DNA Index was inversely correlated with response and one unit raise of DNA Index augmented 6 times the probability of death. Our findings potentiate the prognostic role of BRAF, PIK3CA mutations and ploidy in advanced CRC.

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