CD8A and neoplasm: The relative abundance of different components of the immune system plays a crucial role in the determination of the outcome of immune response: an increase in abundance of tumor-associated macrophages and fibroblasts, Tregs, regulatory B cells, and myeloid-derived suppressor cells (MDSCs) is associated with rapid and unimpeded tumor growth [325], while increase in the abundance of CD8+ cytotoxic T lymphocytes, natural killer (NK) cells, and M1 macrophages and CD4+ T lymphocytes is associated with the direct destruction of tumor cells or with stimulation of this process [326,327].