Genome‐wide analysis of recurrent copy‐number alterations and copy‐neutral loss of heterozygosity in head and neck squamous cell carcinoma

Abstract

Head and neck squamous cell carcinoma (HNSCC) is the eighth most commonly diagnosed malignancy worldwide, and it is generally characterized by a poor prognosis. The aim of our study has been to identify possible recurring genomic abnormalities in this malignancy, likely to have a key role in pathogenesis. The single-nucleotide polymorphism (SNP)-array data relative to 19 HNSCC samples (submitted by Poage et al., PloS ONE 2010; 5: e9651), accessible at NCBI GEO database (GSE20939), were analyzed using criteria that take into account both genotyping and intensity data. By this method, we determined the number and localization of recurrent copy-neutral loss of heterozygosity (CN-LOH) regions and compared them with recurrent somatic copy-number alterations (CNAs). Single-nucleotide polymorphism-array data analysis allowed us to detect, for the first time in HNSCC, chromosomal segment of CN-LOHs in addition to CNAs. Chromosomal alterations have been detected in 14 (73.7%) of 19 samples, and the 12.1% of all alterations observed (LOHs, gains, and CN-LOHs) were CN-LOHs. The most recurrent gain events, occurring in 78.5% of cases (11 samples), were harbored within 8q21.11-q21.13 and 8q23.1-q24.22 loci, while the most recurrent loss and CN-LOH events were present at 3p21.31-p21.1 (57.1%; 8 samples) and 17p13.3-p13.1 (28.6%; 4 samples) loci, respectively. The investigated chromosomal regions, in particular those with CN-LOH, harbored some interesting genes, such as HIC1, DOCK8, KANK1, and NOTCH1 whose role, mutations and epigenetic modifications in HNSCC deserve to be investigated, in order to understand the significance of CN-LOH events in HNSCC pathogenesis.