Galectins are animal lectins, which may play a role in neoplastic transformation. Po66-Carbohydrate Binding Protein (Po66-CBP) belongs to the galectin-8 family and is expressed in lung tumor cells but not in normal ones. Recent studies showed that galectin-8 could be used for human lung squamous cell carcinoma radioimmunotherapy. To optimize this method of treatment, we attempted to increase galectin-8 expression in human lung tumor cells. A human lung squamous (SK-MES-1) or adeno (A 549) carcinoma cell line was grown with or without sodium butyrate. Cell growth, morphology, transcriptional, expression translational expression and cellular localization of galectin-8 were studied. 3 mM of sodium butyrate inhibited the two cell lines' growth after 48 hours of treatment, but only in SK-MES-1 cells galectin-8 expression is modulated without any secretion and cellular localization modifications, apoptosis or necrosis. Sodium butyrate could be an interesting tool in optimizing the radioimmunotherapy of human lung squamous carcinoma, but not of adenocarcinoma.