MUC1 and cancer: MUC1 is also known to be involved in the formation of an immunosuppressive microenvironment since MUC1 (i) increases PD-L1 expression directly at the transcriptional level [29,39,40]; (ii) increases M2 TAMs inside the tumor [41,42]; (iii) decreases MCP-1, IFN-γ, and GM-CSF expression [40]; and (iv) confers cancer cell escape from NK cells [43].