Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Objective: The purpose of the present study was to investigate the expression of the alpha 2-integrin subunit and heat shock protein 47 (Hsp47) in two families with isolated gingival fibromatosis (GF) form and one family with GF associated with dental abnormalities and normal gingiva (NG). Study Design: Immunohistochemistry was performed with antibodies against alpha 2-integrin and Hsp47 in specimens from two unrelated families with hereditary gingival fibromatosis (Families 1 and 2) and from one family with a gingival fibromatosis-associated dental abnormality (Family 3); NG samples were used for comparison. The results were analysed statistically. Results: Immunoreactivity for alpha 2-integrin and Hsp47 was observed in the nucleus of epithelial cells of both the basal and suprabasal layer and a more discreet signal was noted in connective tissue in all study samples. Hsp47 showed higher immunoreactivity in Family 2 compared with the other families (p <= 0.05). Despite the markup alpha 2-integrin was higher in Family 3 there was no statistically significant difference between the families studied (p >= 0.05). Conclusions: Our results confirmed the heterogeneity of GF, such that similar patterns of expression of the condition may show differences in the expression of proteins such as Hsp47. Although no difference in alpha 2-integrin expression was observed between GF and NG groups, future studies are necessary to determine the exact role of this protein in the various forms of GF and whether it contributes to GF pathogenesis.181E45E48Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)