Wnt genes encode a large fami ly of secreted cysteine-rich signaling mol ecules involved in cell growth‘ differentiation and tumorigenesis, Wnt5a, a non-transforming member of the Wnt fa mily behaves as a putative onco 一 gene in many cancers including melanomas, The aim of our study was to determine Wnt5a ex pression pattern in pnmalγ oral mucosal melanomas(Ol\αÆ) and correlate it with tumor thlckness Archival ti ssues from 18 OMM cases were subjected to immunohistochemical detection of Wnt5a by the streptavidin-biotin method , These were categorized into tumors of (4 mm(thin and intermediate thickness lesions) and )4 mm(t hi ck lesions) t hickness, Most OMM cases(17/18; 94, 4%) stained positive for Wnt5a, though heterogeneously, Seven t hi ck(7/11: 64%) and one in termediate thickness(1/7‘ 14%) ol\α‘ demonstrated strongly positive Wnt5a staining(P(O, 05), The only Wnt5a-neg ative case was a thi ck OMM without local recurrence after treatment Strong Wnt5a express ion at tumor adva ncing sites suggests a role in local tumor spread, Identification of pleomorphi c epitheli oid and spindle cells as mel anoma cell populations with the most pronounced Wnt5a staining suggests that Wnt5a overexpression inJ] uences cellular phenotype, These results taken together suggest that Wnt5a is up- regulated in OMM a nd may play a role in tumor progression, Wnt5a activity is most frequently detected in advanced OMM suggesting its function in tumor progression, Expression level of Wnt5a in OMM correlated with tumor grade and t hickness