CD8A and neoplasm: The results showed that MTHFD2 expression was negatively correlated with tumour purity (r = −0.211, p = 4.39e−5) and positively correlated with the levels of infiltrating immune cells, like CD8 + T cells (r = 0.364, p = 6.38e−13), macrophages (r = 0.145, p = 5.49e−3), neutrophils (r = 0.269, p = 2.03e−07) and dendritic cells (r = 0.407, p = 5.62e−16) (Figure 6C).