Genomic assessments of the frequent loss of heterozygosity region on 8p21.3∼p22 in head and neck squamous cell carcinoma

Most human cancers are characterized by genetic instabilities. Chromosomal aberrations include segments of allelic imbalance identifiable by loss of heterozygosity (LOH) at polymorphic loci, which may be used to implicate regions harboring tumor suppressor genes. Here we performed whole-genome LOH profiling on 41 human head and neck squamous cell carcinoma (HNSCC) cell lines. Several frequent LOH regions were identified on chromosomal arms 3p, 4p, 4q, 5q, 8p, 9p, 10p, 11q, and 17p. A genomic region of ∼7 Mb located at 8p21.3∼p22 exhibits the most frequent LOH (87.9%), which suggests that this region harbors one or more important tumor suppressor genes. Mitochondrial tumor suppressor gene 1 (MTUS1) is a recently identified candidate tumor suppressor gene that resides in this region. Consistent downregulation in expression was observed in HNSCC for MTUS1 as measured by real-time quantitative reverse transcriptase-polymerase chain reaction. Sequence analysis of MTUS1 gene in HNSCC revealed several important sequence variants in the exon regions of this gene. Thus, our results suggest that MTUS1 is one of the candidate tumor suppressor genes for HNSCC residing at 8p21.3∼p22. The identification of these candidate genes will facilitate the understanding of tumorigenesis of HNSCC.