CD4 and neoplasm: Zhang et al. [8] used in situ and subcutaneous tumour models of RIPK2-deficient bladder cancer-bearing animals and observed an increase in tumour infiltration of CD11b + Gr1Himyeloid-derived suppressor cells (MDSCs) accompanied by a decrease in CD8+ T lymphocytes, CD4+ T lymphocytes, and NK cells, promoting tumour invasion and metastasis.