Prognostic significance of apoptosis in laryngeal cancer. A quantitative immunomorphological study

The main purpose of the study was to investigate the prognostic significance of apoptosis of cancer cells and to examine the relationship between apoptosis and morphological markers of the host immune response in laryngeal cancer. Apoptotic tumour cells, detected by the TUNEL technique, expression of HLA DR (an antigen belonging to human leukocyte-associated antigens class II) in cancer cells, the number of tumour infiltrating T cells (CD45RO+ cells), B cells (CD20+ cells), macrophages (CD68+ cells) and mast cells as well as the mitotic index were investigated in 28 laryngeal cancers. Sections were studied morphometrically using image analysis. Significant inverse correlations between the number of apoptotic tumour cells and HLA DR-positive tumour cells as well as between the number of apoptotic tumour cells and the number of CD45RO+ cells at the tumour periphery were observed. Analysis of survival showed that patients with high rates of apoptosis had significantly worse prognosis as compared to patients with low apoptotic rates. Differences in HLA DR expression and numbers of CD45RO+ cells were also found between groups of patients with high and low numbers of apoptotic cells. Whether these findings are due to immunosuppressive effects of apoptosis needs further investigation.