Immunological correlations between ontogenesis and oncogenesis: theoretical implications and suggestions for tumor...

The previously hypothesized paraembryonal nature of tumor cells (1) leads one to suggest, immunologically, the presence in a tumor of two main cell populations: one consisting of either genotypically or phenotypically paraembryonal cells (PECs), with no differentiation MHC (major histocompatibility complex) antigens, and representing the stem tumor cells; the other consisting of phenotypically differentiated-paraembryonal cells (DPECs), with either embryonal or differentiated antigens, rising from neighbour genotypically normal cells induced by PECs. PECs, without MHC antigens, might escape alpha beta TCR (T-cell alpha beta receptor) lymphocyte immunosurveillance, since alpha beta TCR T-cells recognize only MHC-restricted antigens, such as DPEC antigens. On the other hand, PECs might be recognized by gamma delta TCR lymphocytes, known to constitute a more primitive immunosurveillance system, able to recognize non-MHC-restricted antigens. On this ground, several immunological aspects of the tumors are analysed and suggestions for a more effective tumor immunotherapy are given.