In detail, PBMC isolated from metastatic colorectal cancer patients treated with pelareorep and chemotherapy in a phase I trial revealed that several pro-inflammatory cytokines IL-12p40, IL-12p70, GM-CSF, and IFN-γ were upregulated at day 8 or 15 after IV administration of pelareorep compared to the baseline, and reduction of pro-tumoral chemokines associated with angiogenesis or immunosuppression, like IL-8, VEGF, and RANTES/CCL5, was observed. The gene discussed is CCL5; the disease is metastatic colorectal cancer.