CD4 and neoplasm: Further, we found a decrease in the frequency of IFN-γ producing CD8+ and CD4+ T lymphocytes in the spleen as well as in the tumor draining lymph nodes (dLN) in the group of mice transferred with gefitinib-treated OT-II Th9 cells as compared to OT-II-Th9 cells (Fig. 2d, e and Supplementary Fig. 2a–f).