Glottic versus supraglottic tumors: differential molecular profile.

Glottis and supraglottis, although anatomically interconnected, are embryologically distinct. Moreover, squamous cell carcinomas arising from these subsites, differ in terms of epidemiology, risk factors, clinical behaviour and prognosis. This study aims to explore any possible differences between their molecular profiles. We investigated in the two tumor types, the expression of epidermal growth factor receptor (EGFR), nuclear factor-kappaB (NF-kappaB) and retinoid X receptor alpha (RXRalpha), principal signal transducers associated with cancer, as well as cyclooxygenase-2 (COX-2), an enzyme induced in malignant neoplasms. The clinical material includes tumor specimens from 61 patients with laryngeal cancer of glottic or supraglottic origin. Subsite groups were matched for gender, age and histological grade. Paraffin-section immunohistochemistry was performed, to detect the aforementioned molecules. Staining patterns were membranic and cytoplasmic for EGFR, purely cytoplasmic for COX-2, nuclear for RXRalpha and cytoplasmic, as well as nuclear, for NF-kappaB. Intense EGFR and RXRalpha expression was significantly associated with glottic tumor descent (P = 0.011 and 0.001, respectively). No significant relationship was established between neoplasm location and expressions of NF-kappaB, COX-2. Our results show that tumors emerging from the two laryngeal regions, are different with regard to their molecular constitution. Upregulation of EGFR and RXRalpha in carcinomas of the glottis, might be important in the design of subsite-specific chemotherapeutic approaches.