Distinct regions of loss of heterozygosity on 22q in different sites of head and neck squamous cell carcinomas.
BACKGROUND
Frequent loss of heterozygosity (LOH) has been reported in many types of cancer, including head and neck carcinomas. Somatic deletions involving specific chromosomal regions are strongly associated with inactivation of the allele of a tumor suppressor gene located within the deleted region. In most studies concerning LOH in head and neck squamous cell carcinomas (HNSCC) the different anatomical sites are not distinguished. The behavior of tumors arising at various sites differs significantly, however, suggesting different intrinsic tumor properties. In this study we compared the LOH on 22q and its relationship to clinicopathological parameters at the three major sites of HNSCC: oral cavity, larynx and pharynx.


METHODS
LOH and microsatellite instability (MSI) were studied using seven polymorphic microsatellite markers mapped to the 22q11-q13.3 region in 37 oral, 32 laryngeal, and 31 pharyngeal carcinomas.


RESULTS
Two separate regions of LOH were identified in the laryngeal (22q11.2-12.1) and oral cavity (22q13.1-13.31) tumors. When the different anatomical sites were compared, a statistically significant difference was found between the presence of LOH at D22S421 (p<0.001), D22S315 (p=0.014) and D22S929 (p=0.026) in the laryngeal tumors.


CONCLUSIONS
These data suggest that distinct regions on 22q are involved in LOH in oral cavity and laryngeal tumorigenesis, but do not support a similar association between the development of pharyngeal tumors and genes located on 22q. These findings implicate the presence of different tumor suppressor genes mapping to distinct regions on chromosome 22q in oral and laryngeal carcinomas.
dos Reis
Patricia Pintor
PP
Department of Genetics, IB, UNESP, Botucatu, SP, Brazil.
Poli-Frederico
Regina Célia
RC
dos Santos
Rodrigo Mattos
RM
Nishimoto
Ines Nobuko
IN
Kowalski
Luiz Paulo
LP
Rogatto
Silvia Regina
SR
D000483:Alleles; D002277:Carcinoma / Q000235:genetics*; D002892:Chromosomes, Human, Pair 22; D017353:Gene Deletion; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D007822:Laryngeal Neoplasms / Q000235:genetics; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D008957:Models, Genetic; D010610:Pharyngeal Neoplasms / Q000235:genetics