A Possible Functional Role of HSP27 as a Molecular Chaperone of Wnt1 in Cell Differentiation of Pleomorphic Adenomas

The study focused on the differentiation of parenchymal tumor cells in pleomorphic adenomas. According to our previous published data, Wnt1 is involved in squamous differentiation of basaloid cells in solid nests and small cuboidal cells in duct-like structures during cell differentiation in pleomorphic adenoma. Furthermore, HSP27 sometimes act as a molecular chaperone in neoplastic cells. Thus, immunohistochemistry was performed using Wnt1 and HSP27. A total of 30 cases of pleomorphic adenoma were re-evaluated histologically and categorized based on WHO classification. The mean age of the patients is 51.5 years consisting of 13 males and 17 females. Fourteen tumors were located in the palate, 5 in the parotid gland, 4 in the mandibular gland, 3 in the upper lip, 3 in the buccal mucosa and 1 in other region. Wnt1 and HSP27 expressions were observed under a light microscope. Wnt1 was detected in almost all tumor cells. The basaloid cells with squamous metaplasia and small cuboidal cells forming duct-like structures were strongly positive to Wnt1. The immunofluorescent staining pattern of Wnt1 and HSP27 was consistent with previous results. The results suggest that Wnt1 and HSP27 are involved in tumor cell differentiation of basaloid cells in solid nests and small cuboidal cells in duct-like structures. Moreover, HSP27 is highly involved in cell differentiation such as the formation of squamous metaplasia in solid tumor nests. Since HSP27 expression was similar to Wnt1, it can be inferred that HSP27 works as possible molecular chaperone in Wnt1 signaling.