Immunohistochemical detection of intercellular adhesion molecule-1 (ICAM-1) and major histocompatibility complex class I antigens in seminoma.

Expression of intercellular adhesion molecule-1 (ICAM-1) and major histocompatibility complex (MHC) antigens, and characterization of tumor-infiltrating mononuclear cells (TIM) were examined immunohistologically in 10 specimens of seminoma. ICAM-1 and MHC antigens were not detected on normal spermatogenic cells. ICAM-1 and MHC class I antigens were variably expressed in 7 and 9 seminomas, respectively, whereas class II antigens were not detected. Although the degree of expression of ICAM-1 and MHC antigens was not correlated with any clinical or histopathological factors, neither of the antigens was detected on an anaplastic seminoma. Various numbers of TIM were detected in all of the seminoma, and comprised mainly T cells bearing the lymphocyte function-associated antigen (LFA)-1. No significant correlation was noticed between the degree of lymphocyte infiltration and ICAM-1 or MHC antigen expression. Although ICAM-1 and MHC class I antigens were expressed in seminoma, possibly facilitating an anti-tumor reaction of host, their expression remained low in several cases, despite marked lymphocyte infiltration within the tumor.