Expression patterns of cyclin E, cyclin A and CDC25 phosphatases in laryngeal carcinogenesis.

The aim of the research was to evaluate the expression levels of cyclin E/A and CDC25A/B during laryngeal carcinogenesis. The expression was demonstrated using immunohistochemistry in 46 cases of laryngeal cancer (LSCC), 23 epithelial dysplasias (ED) and 21 samples of normal mucosa (NM). The mean labeling indices (LI) for cyclin E in LSCC, ED and NM were 10.6, 4.9 and 0%; for cyclin A 27.2, 17.5 and 7%; for CDC25A 73.9, 53 and 32% and for CDC25B 36.5, 25.9 and 0%, respectively. A gradual increase in cyclin A and CDC25A expression levels from mild through moderate and severe dysplasia to in situ carcinoma were noted. Cyclin A LI significantly increased also from NM through ED to LSCC. Cyclin A and CDC25A LI significantly increased from NM to ED. Overexpression of cyclin A and CDC25A was significantly associated with proliferation among ED. Linear interdependency was detected in ED between the expression of CDC25A and cyclin A. Cyclin E and CDC25B overexpression occurs as a late event in neoplastic transformation. The progressive expression of proteins supports the multistep model of laryngealcarcinogenesis. The results indicate a possible role of cyclin A as a marker reflecting cell proliferation. The enhanced immunoexpression of cyclin A and CDC25A suggests the potential for malignant formation in preneoplastic lesions.