Estradiol receptor profile and estrogen responsiveness in laryngeal cancer and clinical outcomes

Nofrat Schwartz, Anjali Verma, Chandana Muktipaty, Caroline Bivens, Zvi Schwartz, Barbara D Boyan

There is growing evidence that laryngeal cancers are responsive to sex hormones, specifically 17β-estradiol (E2), despite controversy regarding the presence and characterization of E2 receptors (ER). Determination of sex hormone responsiveness impacts the prognosis of laryngeal cancer patients and the treatment modalities implemented by their clinicians. Discovery of membrane-associated steroid hormone receptors and rapid membrane signaling opened the possibility that cancers previously labeled 'non-hormone dependent' and 'ER negative' might in fact be susceptible to the effects of E2 via these membrane receptors. ERα66 and ERβ, the classical nuclear receptors, are present in the membranes of different cancer cells via a mechanism referred to as trafficking. Novel splice variants of these traditional receptors, a key example being ERα36, have also been found in the caveolae of cancer cells. Previous work demonstrated that ERα36 has a role in the tumorigenesis of laryngeal cancer, enhancing both proliferation and the anti-apoptotic effect of E2 against chemotherapeutics. The present study showed that expression of different membrane ERs in laryngeal cancer is not uniform, which may result in differential and even antagonistic responses to E2. E2 had protective or deleterious effects in different cancer cell lines, stimulating proliferation and conferring anti-apoptotic potential to the cancer cells according to their receptor profile. These findings stress the importance of establishing the molecular and clinical characterization of the specific laryngeal tumor in order to tailor treatment accordingly, thus optimizing care while reducing adverse effects for individual patients.