Tumour infiltrating lymphocytes in relation to tumour angiogenesis, apoptosis and prognosis in patients with large cell lung carcinoma.

Immune escape of tumour infiltrating lymphocytes (TILs), angiogenesis and apoptosis are important factors that contribute to tumour growth. In the present study immunohistochemical methods were used to investigate the relationships of these factors and their role in the prognosis of 38 patients operated on for a large cell lung carcinoma (LCLC). T cells and macrophages were most commonly found TILs in LCLC while the number of intratumoural B cells was small. A high number of intratumoural macrophages associated with angiogenesis, as measured by microvessel density (MD). TILs were not associated with the extent of apoptosis in LCLC, as measured by in situ 3'-end labelling of apoptotic DNA. The high number of intratumoural macrophages and B cells was a prognostic marker showing a better survival time of the patients with LCLC. Furthermore, a high number of intratumoural macrophages was significantly associated with longer disease free survival and low tumour stage of the patients with LCLC. A high number of intratumoural B cells and macrophages was associated with a small tumour size suggesting that both B cells and macrophages are important TILs limiting the growth of LCLC. Instead, T cells were not associated with survival or with the size or stage of the tumour suggesting that cytotoxic T cells are less important mediators of tumour host interaction in LCLC than B cells and macrophages.