Acta Otorrinolaringol Esp. 2016;67(3):130---134 www.elsevier.es/otorrino ORIGINAL ARTICLE HSP-90 Expression as a Predictor of Response to Radiotherapy in Head and Neck Cancer Patients  Jacinto García Lorenzo, a,* Xavier León Vintró, a Mercedes Camacho Pérez de Madrid b a Servicio de Otorrinolaringología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain b Laboratorio de Angiología, Biología Vascular e Inflamación. Instituto de Investigación Biomédica Sant Pau, Barcelona, Spain Received 10 February 2015; accepted 17 March 2015 KEYWORDS HSP90 Heat-Shock Proteins; Head and neck neoplasms; Radiotherapy; Local neoplasm recurrence Abstract Introduction and objectives: HSP-90 is an intracellular protein that protects the cell from envi- ronmental stress situations. The overexpression of HSP-90 isoforms could serve as a mechanism of resistance to radiotherapy for tumour cells. We studied this effect in a sample of head and neck tumours. Methods: We included 87 patients diagnosed with oral cavity, oropharynx, larynx and hypophar- ynx tumours. We studied the expression of the HSP-90 isoforms by real-time PCR on pre-treatment biopsy samples. We analysed the relationship between HSP-90 expression levels and local relapse of the tumour with CRT decision trees. Results: The expression levels of the inducible cytosolic isoform (HSP90AA) allowed the def- inition of two groups of patients with different rates of local relapse. The group with a low expression level showed a 2.9% local relapse rate, while the group with a high expression level showed a 38.2% rate. Survival curves showed differences in time to local relapse for both groups of patients. These differences did not reach statistical significance. Conclusions: Radiotherapy response was related to expression levels of HSP-90 in a sample of head and neck cancer patients. This result could prove useful in the selection of treatments for this group of patients. © 2015 Elsevier Espa˜ na, S.L.U. and Sociedad Espa˜ nola de Otorrinolaringolog´ ıa y Cirug´ ıa de Cabeza y Cuello. All rights reserved.  Please cite this article as: García Lorenzo J, León Vintró X, Camacho Pérez de Madrid M. Expresión de Heat Shock Protein-90 (HSP-90) como factor predictor de la respuesta a radioterapia en pacientes con tumores de cabeza y cuello. Acta Otorrinolaringol Esp. 2016;67:130---134. ∗ Corresponding author. E-mail address: jgarcial@santpau.cat (J. García Lorenzo). 2173-5735/© 2015 Elsevier Espa˜ na, S.L.U. and Sociedad Espa˜ nola de Otorrinolaringolog´ ıa y Cirug´ ıa de Cabeza y Cuello. All rights reserved.