After chemotherapy, gemcitabine obviously induced a Th2 biased cytokine microenvironment characterized by higher level of interleukin-4 (IL-4), interleukin-10 (IL-10) and TGF-β, as well the percentages of B cells, dendritic cells (DC) and M2 in peripheral blood and tumor tissue were significantly elevated, on the contrary, the percentages of intratumoral Th cells and CTL, and that of MDSC in peripheral blood and tumor tissue were decreased as well. Here, IL4 is linked to neoplasm.