Analysis of immune response in oral tumors

Currently, there is widespread disagreement over the role of the immune system in controlling, via the major histocompatibility complex, the organism's response to cells in the process of tumoral degeneration. One possible mechanism by which tumoral cells escape detection by the antitumoral surveillance system is the lack of expression of HLA class I molecules. The APAAP technique was used to study the levels of expression of these molecules and other cell markers on 27 oral cavity tumors. Heterogenous class I expression was recorded, some tumors completely lacking class I antigens. Similar patterns of expression were found for beta-2 microglobulin and ABC molecules (different class I chains encoded in different chromosomes). The number of DR/DP positive cells was similar to the number of immune cells infiltrating the tumors. Statistical analyses failed to show any significant relationship between class I antigen expression and the anatomoclinical parameters of tumoral aggressivity considered.