Galectin-3 Expression Correlates with Apoptosis of Tumor-Associated Lymphocytes in Human Melanoma Biopsies

MARIANA RODRÍGUEZ ZUBIETA, DAVID FURMAN, MARCELA BARRIO , ALICIA INÉS BRAVO, ENZO DOMENICHINI AND JOSÉ MORDOH

Paris, Francia

Congreso; 1st Joint Meeting of European National Societies Immunology. 16th European Congress of Immunology; 2006

EFIS

The immune system recognizes diverse melanoma antigens. However, tumors can evade the immune response, therefore growing and progressing. It has been reported that galectin-3and galectin-1 can induce apoptosis of activated lymphocytes. However, there is strong evidence indicating that the regulation of galectins function in the human tumor microenvironment is a complex process that is influenced by diverse biological circumstances. Here, we have investigated 33 biopsies (eight primary and 25 metastases)from 24 melanoma patients (15 72 years old) and describe the correlation between theexpression of galectin-3 or galectin-1 and the level of apoptosis of tumor-associated lymphocytes using immunohistochemistry and an in situ nick translation assay. The range ofgalectin-3-positive tumor cells varied between 0% and 93% and that of galectin-1-positivetumor cells varied between 5% and 97%. In addition, 23 ± 27% of tumor-associated lymphocytes were apoptotic. Although our results show a correlation between galectin-3expression and apoptosis of tumor-associated lymphocytes, we could not find such correlation with galectin-1. Considering the complex process of cancer immunoediting, various interacting factors must be considered.