CD4 and neoplasm: CD4+ T helper type 1 (Th1) cells secrete the cytokine interferon (IFN)-γ and affect tumor growth by targeting the tumor microenvironment (TME), antigen presentation through major histocompatibility complex (MHC) class I and MHC class II, and other immune cells (Alspach et al., 2019; Beatty and Paterson, 2001; Bos and Sherman, 2010; Kammertoens et al., 2017; Qin and Blankenstein, 2000; Tian et al., 2017).