Telomerase activity is upregulated in laryngeal squamous cell carcinoma

Objective/Hypothesis: The immortalizing enzyme telomerase has been linked t o carcinogenesis and is being targeted as a novel molecular marker. This st udy investigated telomerase expression in patients with laryngeal squamous cell carcinoma and correlated telomerase activity with conventional prognos tic parameters. Study Design: A consecutive series of patients with larynge al squamous cell carcinoma undergoing surgical salvage for persistent or pr ogressive disease after failed radiation therapy. Methods: Twenty patient s amples of laryngeal squamous cell carcinoma and 20 adjacent histologically normal mucosal samples were assayed using the telomeric repeat amplificatio n protocol (TRAP) method for detection of telomerase activity. The leukemic cell line, K562, acted as a positive control and the human fibroblast line , Hs21Fs, as a negative control. A sample was classified as telomerase posi tive when an RNase-sensitive hexameric repeat ladder was observed. Absence of laddering was considered a negative result. Results: Seventeen of 20 (85 %) tumor samples and 4 of 20 (20%) adjacent histologically normal samples w ere telomerase positive. No statistically significant difference was observ ed when densitometric readings were compared by T category, tumor grade, or site (by ANOVA). Conclusions: Although telomerase activity is present in l aryngeal cancer, levels of activation do not correlate with conventional pa rameters used for prognostication, Our study indicates that the marker may be a useful adjunctive method in the diagnosis of malignancy after radiatio n failure.