GALECTIN-3, A BETA-GALACTOSIDE-BINDING ANIMAL LECTIN, IS A MARKER OF ANAPLASTIC LARGE-CELL LYMPHOMA

Galectin-3 is a member of a newly named family of beta-galactoside-bin ding animal lectins, which has been described with a number of possibl e important biological functions, including the regulation of cell gro wth and association with tumor transformation. This protein has a wide tissue distribution but is notably not expressed by normal lymphocyte s. We have previously shown that galectin-3 is markedly up-regulated i n HTLV-1-infected T cells, most likely mediated by the viral transacti vating protein Tax. In this study, we surveyed various lymphomas by im munohistochemistry and found the expression of galectin-3 in all of th e 8 cases of Ki-1(+) anaplastic large-cell lymphoma (ALCL). Immunoreac tivity for galectin-3 was found in a majority of the neoplastic cells in the ALCLs studied. In contrast, only 2 of the 35 cases of other typ es of lymphoma, including various Hodgkin's and non-Hodgkin's lymphoma s, were positive. Unlike the cases of ALCL, immunoreactivity for galec tin-3 in these 3 cases was found only sporadically in a small number o f neoplastic cells. Thus, galectin-3 may prove to be a useful marker f or ALCL and its expression in neoplastic cells in ALCL may contribute to the biological behavior of this specific type of lymphoma.