West Asia Organization for Cancer Prevention (WAOCP), APOCP's West Asia Chapter. Asian Pacific Journal of Cancer Prevention 1513-7368 19 7 2018 07 01 Proliferative Activity of Myoepithelial Cells in Normal Salivary Glands and Adenoid Cystic Carcinomas Based on Double Immunohistochemical Labeling 1965 1970 65368 10.22034/APJCP.2018.19.7.1965 EN Faisal Alali Department of Maxillofacial Surgery, Diagnostic Sciences, Prince Sattam Bin Abdulaziz University, Faculty College of Dentistry, Saudi Arabia. Nabil Kochaji Department of Oral Histology and Pathology, Faculty of Dentistry, Damascus University, Damascus. Syria. Founding Dean, Faculty of Dentistry, Al-Sham Private University, Syria. Journal Article 2018 03 01 Objective: To investigate the proliferative activity of myoepithelial cells (MEC) in normal salivary glands (NSG)<br />and adenoid cystic carcinomas (ACC)) Study design. Twenty -three salivary gland specimens (13 ACC, 10 NSG)<br />were studied using double immunohistochemical labeling for α smooth muscle actin (a-SMA) and proliferative cell<br />nuclear antigen (PCNA)). Results: There was a significant difference in PCNA reactivity in normal samples between<br />myoepithelial cells of the parotid glands and of the submandibular glands, rates being higher in the latter. Neoplastic<br />myoepithelial cells exhibited higher expression than neoplastic epithelial cells. In addition, myoepithelial cells of the<br />cribriform type of ACC showed PCNA reactivity lower than those of the tubular type, whereas there was no statistically<br />significant difference in epithelial cell rates. We could not identify myoepithelial cells in solid pattern due to α-SMA<br />negativity; although high PCNA reactivity was evident. Conclusion: These data suggest that the myoepithelial cell has a<br />key role in ACC oncogenesis, more so than its epithelial cell counterparts. Moreover, the data provide a histopathological<br />interpretation for aggressive clinical features of submandibular ACC, as the myoepithelial cells were less differentiated<br />as compared to those of parotid glands. https://journal.waocp.org/article_65368_6d7af8c67ccc8000b05848efc436143a.pdf