Expression pattern of PLUNC proteins as an auxiliary tool for the diagnosis of high-grade mucoepidermoid carcinoma of the salivary gland.

BACKGROUND: Mucoepidermoid carcinomas are the most frequent malignant neoplasia of the salivary glands and are histologically classified as low, intermediate, and high grade. At present, histochemical stains such as periodic acid-Schiff or mucicarmine are useful tools in making a diagnosis. Recently, expression of the PLUNC proteins has been described in mucin-producing salivary gland tumors, with the suggestion that they could provide a powerful tool for the diagnosis of difficult cases. METHODS: This study evaluates the expression of PLUNC proteins in 30 cases of salivary gland mucoepidermoid carcinomas. Tumors were reviewed and classified according to histological grade. Periodic acid-Schiff, mucicarmine, and immunohistochemical staining for SPLUNC1, LPLUNC1, SPLUNC2, and LPLUNC2 were carried out. Immunostaining was classified as positive or negative. RESULTS: The majority of the tumors (63%) were classified as low grade, 13% were intermediate grade, and 23% were high grade. SPLUNC1 (90%) and LPLUNC1 (93%) were positive in the majority of cases, mainly in mucous cells, mucin plugs, and intermediate cells. SPLUNC2 and LPLUNC2 did not present significative expression within the tumors; however, LPLUNC2 was found to stain positively in mast cells in 83% of the samples. CONCLUSIONS: SPLUNC1 and LPLUNC1 showed a similar pattern of expression and could prove useful in the diagnosis of high-grade cases because of the differential staining in intermediate and epidermoid cells. The expression of LPLUNC2 in mast cells has not previously been reported, but further studies are necessary to validate this finding and to determine its significance.

Salivary gland tumors: immunohistochemical study of EGF, EGFR, ErbB-2, FAS and Ki-67.

OBJECTIVE: To analyze the expression of ErbB-1 (Her-1 or EGFR), ErbB-2 (Her-2 or neu), ErbB-3 (Her-3) and ErbB-4 (Her-4) and their correlation in 3 different types of salivary gland tumors. STUDY DESIGN: Immunohistochemical expression of epidermal growth factor (EGF), EGFR, ErbB-2, fatty acid synthase (FAS) and Ki-67 were analyzed in 41 pleomorphic adenoma (PA), in 30 mucoepidermoid carcinoma (MEC) and in 30 adenoid cystic carcinoma (ACC) and correlated with their histologic patterns. RESULTS: EGF was more common in MEC and PA, but MEC had a higher percentage of strongly positive cases. EGFRc and EGFRm were both more frequent in MEC and ACC. Higher scores of ErbB-2c were observed in PA, followed by MEC and ACC. In contrast, higher scores of ErbB-2m were more common in MEC as compared to ACC and PA. FAS was most commonly found in PA and MEC. Moreover, MEC showed the highest percentage of strongly positive cases. Ki-67 was higher in MEC and ACC than in PA. From a correlation of immunomarkers with the histologic patterns, it was observed that cribriform ACC presented more expression of EGFR and high grade MEC showed a higher percentage of ErbB-2, FAS and Ki-67. CONCLUSION: EGF, EGFR, ErbB-2 and FAS were commonly found and seem to be important in the tumorigenesis of salivary gland tumors, particularly in percentage of strongly positive cases. Ki-67 was higher in MEC and ACC than in PA. From a correlation of immunomarkers with the histologic patterns, it was observed that cribriform ACC presented more expression of EGFR and high grade MEC showed a higher percentage of ErbB-2, FAS and Ki-67. CONCLUSION: EGF, EGFR, ErbB-2 and FAS were commonly found and seem to be important in the tumorigenesis of salivary gland tumors, particularly in MEC. (Anal Quant Cytol Histol 2009;31:280-287)