Loss of heterozygosity in laryngeal squamous cell carcinoma

Background: Loss of function of tumor suppressor genes is important in the origin and progression of malignant tumors. Analysis for loss of heterozygosity (LOH) in tumors has been used to detect chromosomal regions that could harbor these genes. Methods: We investigated 30 paired samples of tumor and normal DNA of 20 patients with laryngeal squamous cell carcinoma. Using polymerase chain reaction (PCR), we studied microsatellite polymorphisms on 3 p, 5q, 9 p, 9q, and 17 p. We separated PCR products by denaturating gel electrophoresis and then visualized them colorimetrically. Results: Allelic loss was observed most frequently on 3 p (45%), followed by 9 p (15%), 17 p (6%), and 5q (5%), while chromosome 9q displayed no LOH. When primary tumor and lymph node metastases were investigated, the same genetic pattern was observed. No correlation was found between LOH and tumor stage. The commonly deleted region of 3 p was at the chromosomal bands 3 p24-3 p25. Our data demonstrate that chromosome 3 p allelic loss is a common event in head and neck cancers and suggest that tumor suppressor genes on chromosome 3 p contribute to the pathogenesis of these tumors. Conclusions: A longer follow-up will reveal if the assessment of LOH can be associated with prognostic significance in laryngeal carcinomas.