Galectin-3 and CD1a-positive dendritic cells are involved in the development of an invasive phenotype in vulvar squamous lesions.

In this study, the expression patterns of Galectin-3 (Gal-3) and the frequency of infiltrating CD1a positive dendritic cells (DCs) were determined in 82 cases of vulvar tissues, consisting of normal squamous epithelia (NE, N = 10), vulvar condylomas (VC, N = 24), high grade vulvar intraepithelial neoplasias (HG-VIN, N = 26) of common type, and invasive keratinizing squamous cell carcinomas (SCC, N = 22) by a standard immunohistochemical method using monoclonal antibodies to investigate their differential expression in vulvar squamous dysplasia and infiltrating carcinomas with an emphasis on neoplastic transformation and progression. Gal-3 expression was cytoplasmic, nuclear or membranous in NE, VCs, and HG-VINs, with negative or weak and occasionally moderate reactivities. In SCCs, exclusively cytoplasmic staining patterns with moderate or strong reactivity in 59% of cases were observed (p < 0.0001, chi-square test); Gal-3 expression was not related with stage, grade, and recurrence. The frequency of CD1a positive DCs increased from NE and VCs to highest numbers in HG-VINs, was lowest in SCCs (p < 0.0001, ANOVA), and was not related with stage and grade, but with recurrence in SCCs (p = 0,048, t-test). This study indicates that qualitative and quantitative changes of Gal-3 immunoexpression and infiltration by CD1a positive DCs in vulvar NE, VCs, and HG-VIN lesions, respectively, compared with SCCs play a role in the development of an infiltrative phenotype, and may provide adjunctive criteria in the diagnosis of invasion of vulvar squamous epithelia.