Immunology and growth characteristics of ocular basal cell carcinoma

Background: Knowledge about immunological features and growth characteristi cs of palpebral (ocular) basal cell carcinomas (BCCs) is limited. In partic ular, it is unclear whether ocular BCC represents in this regard a special BCC entity or not. Methods: Twenty BCCs of the lid area (ocular BCCs) were investigated immunohistologically using monoclonal antibodies against CD4, CDs, CD45Ro, CD50, CD68, HECA-452, Ki67 (MIB1), and the p53 epitope. For co mparison, nine BCCs excised distant from the eye (non-ocular BCCs) were eva luated. Results: In BCCs the distribution of the immunocompetent cells inve stigated is markedly irregular. These cells are localized mainly around BCC islands. Only a few of them invade tumour cell aggregates. The CD4:CD8 rat io as detected by immunohistochemistry is >1 in 82% of ocular BCCs and in 8 8% of nonocular BCCs. Often there are dense infiltrations of CD68+ cells (m acrophages) and HECA-452+ cells adjacent to tumour cell aggregates. The gro wth fraction [percentage of proliferating (Ki67+/MIB1+) cells] varies from 0% to more than 30%. Proliferative activity is enhanced at the invasion fro nt. Additionally, the amount of p53+ cells differs considerably among the B CCs. Conclusions: CD4+ T cells seem to be the most important cell populatio n for BCC immunosurveillance, offering the chance for conservative interfer on therapy. The role of CD68+ and HECA-452+ cells has to be further elucida ted. In many tumours the large amount of proliferating cells contrasts to t he usually slow growth of BCCs, indicating strong apoptotic processes. The results can be regarded only as semiquantitative. So far, ocular and nonocu lar BCCs exhibit no essential differences regarding immunocompetent cell in filtration and growth characteristics. According to this, palpebral BCCs ar e "normal" BCCs and not a special BCC variant. Therefore, results from derm atological research concerning BCC can be extended without limitations to t heir counterparts in the lid area.