CTLA4 and neoplasm: Firstly, high percentages of CD45+CD3+ T cells in the tumour tissue collected from untreated animals on day 4 post-tumour inoculation consisted of Treg subsets, i.e. ~ 16.93 ± 3.88% of CD4+(CD8−)CD25+FOXP3+, known as conventional CD4+ Tregs, ~ 14.23 ± 3.83% of CD8+(CD4−)CTLA-4+ Tregs and that these proportions increased rapidly along with tumour progression to 26.06 ± 3.37% and 35.85 ± 3.53%, respectively, on day 11 (Fig. 6A).