MKI67 and neoplasm: Interestingly, we observed a 2.3-fold increase in the percentages of proliferative Ki-67+CD8+ T cells, as well as a 1.7-fold increase in TCF-1+CD8+ and 2.5-fold increase in TCF-1+CD4+ T cells (Fig. 2, H and I), which have been attributed a function in the persistent control of tumor growth (13).