Before revision: There are several mechasnims that lead to escape of cancer cells to immune system, for example downregulation or loss of expression of classical MHC class I (HLA-A, HLA-B- HLA-C) which is essential for effective T cell-mediated immune response (appears in up to 90% of tumours), development of cancer microenvironment which has suppressive effect on immune system and works as an protective barrier to cancer cells.
After revision: There are several mechanisms that lead to escape of cancer cells to immune system, for example downregulation or loss of expression of classical MHC class I (HLA-A, HLA-B- HLA-C) which is essential for effective T cell-mediated immune response (appears in up to 90% of tumours), development of cancer microenvironment which has suppressive effect on immune system and works as an protective barrier to cancer cells.