Expression of the chemokine CCL28 in pleomorphic adenoma and adenolymphoma of the human salivary glands.

Recent studies have proposed that the chemokine CCL28 is constitutively expressed by epithelial cells in salivary glands and play an important role in lymphocyte trafficking in oral immunity. To date, there is little information on the expression pattern of CCL28 in salivary gland tumors. The purpose of this study was to determine the expression of CCL28 in pleomorphic adenoma and adenolymphoma and to evaluate its potential function in regulating oral carcinogenesis. Immunohistochemical reactivity revealed CCL28 protein expression in the cytoplasm of acinar epithelial cells, both in tumorous tissues and normal adjacent tissues. The level of CCL28 mRNA was markedly reduced in 70% (28/40) of pleomorphic adenomas, and in 81% (26/32) of adenolymphomas, compared to the normal adjacent tissue. CCL28 protein expression was significantly lower in pleomorphic adenomas (P=0.0027, n=40) and in adenolymphomas (P=0.0003, n=32) compared to their normal adjacent tissues. Additionally, the CCL28 protein levels in saliva in the aforementioned patients were lower than those in healthy volunteers. Our study indicated that the reduced expression of CCL28 could possibly be a strategy by recruiting fewer antitumor immunocompetent cells to salivary glands. The expression and secretion of CCL28 may be associated with the pathogenesis of pleomorphic adenoma and adenolymphoma.