Variability of genetic alterations in different sites of head and neck cancer

Objective: Tumors arising hom different sites of the head and neck area hav e different clinical behavior, However, most of the studies on genetic alte rations in head and neck squamous cell carcinomas do not make a distinction between the sites within this area, The objective of this study is to comp are the genetic alterations in three different sites of the head and neck. (larynx, oropharynx, and hypopharynx), Study Design: Prospective study. Met hods: Thirty-eight laryngeal, 29 oropharyngeal, and 37 hypopharyngeal carci nomas were studied. DNA from tumor and healthy tissue was evaluated for amp lification of the oncogenes at 11q13 region (CCND1, FGF3, FGF4 and EMS1) an d of the oncogenes MYC and ERBB1; for integration of the human papillomavir us (HPV) types 6b and 16; for loss of heterozygosity (LOH) at p53 and NAT2; and for the cellular DNA content. Results: FGF4 and FGF4 showed a signific antly higher frequency of amplification in hypopharyngeal tumors (P = .006 and P =,0002, respectively). CCND1 amplification had a nearly statistically significant (P = .072) higher frequency of amplification in hypopharyngeal tumors, Aneuploid tumors were found in a significantly lower proportion in the larynx (P = .03) compared with the other sites. For the other genetic alterations, no significant differences among the three sites were found. C onclusions: These results suggest that cancers originating from different s ites in the head and neck may have different tumor biology. Therefore, they should be considered as different entities.