Molecular Genetics of Head and Neck Cancer

Lyon L. Gleich, MD, Frank N. Salamone, MD

Disclosures

Cancer Control. 2002;9(5) 

In This Article

Multiple Molecular Aberrations in Head and Neck Cancers

Multiple genetic abnormalities are present in head and neck cancers. The exact number and type of abnormality differs from tumor to tumor, resulting in different phenotypes. Evaluating the genotype of head and neck tumors at multiple loci may provide more prognostic information.

The multiple genetic abnormalities present in head and neck cancer cells can be evaluated at the chromosomal level using spectral karyotyping (SKY) and comparative genomic hybridization (CGH). The SKY technique involves labeling each chromosome with a unique colored marker. Rearrangements can be identified when a combination of colors is seen on a single derived chromosome. Using this technique, frequent breakpoints were found in multiple chromosomes of head and neck cancer cells.[86] Identification of rearrangement sites allows for investigation of candidate oncogenes and tumor suppressor genes at these locations. Similar information can be obtained using CGH, in which tumor DNA is labeled with a specific colored marker and hybridized with DNA isolated from normal cells and stained with a different marker. Differences in gene copy number can be determined by the relative amount of staining. CGH has revealed frequent losses and gains on multiple chromosomes.[87]

LOH analysis provides a rapid method of screening for multiple genetic abnormalities. In a study of 68 head and neck cancers, significant LOH was seen at chromosome bands 3p21, 3p25-26, 8pter-21.1, 13q14, and 17p12. LOH at more than two loci was correlated with a poor prognosis.[88] A study of 43 head and neck tumors also revealed that tumors with abnormalities in more than one gene (p53, Rb, q16, cyclin D1, p16, p21, and p27 were tested) had a poorer prognosis.[75]

Newer techniques such as gene array technology that can evaluate a number of genes simultaneously have also shown additional potential sites of genetic abnormalities.[89] As more information on these techniques accumulates,patterns of gene abnormalities that correlate with prognosis may be found.

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