Bcl-Xl protein expression in laryngeal squamous cell carcinoma

The Bcl-2 family of proteins regulate one of the steps in an evolutionary conserved apoptotic pathway. The long splice variant of Bcl-X (Bcl-Xl) is a potent antagonist of apoptosis. The aim of the study was to evaluate the relation between the presence of immunohistochemically detectable Bcl-Xl protein in laryngeal squamous cell carcinomas (LSCCs) and clinicopathological data, as well as DNA ploidy status and proliferative activity. In 50 specimens of LSCC, Bcl-Xl protein expression was evaluated immunohistochemically. Proliferative activity (SG(2)M-phase index) and DNA ploidy were measured by flow cytometry. In our study, Bcl-Xl protein expression decreased with decreasing tumour differentiation (P = 0.04). The majority of patients with Bcl-Xl protein immunoreactivity had no metastatic lymph node involvement (P = 0.01). Other factors such as age, gender, primary tumour size (pT) and type of cancer (keratinizing/non-keratinizing) were not associated with Bcl-Xl protein level. There was no correlation between Bcl-Xl protein and SG(2)M-phase index or DNA ploidy status. Our findings show that expression of Bcl-Xl protein is increased in a great fraction of laryngeal cancers. Further studies, however, are needed to clarify association between Bcl-Xl protein expression and clinical course of patients.