Early stage laryngeal cancer can be effectively cured by radiotherapy or conservative laryngeal surgery. In the UK, radiotherapy is the preferred first line treatment. However, up to 25% of patients with T2 tumours will demonstrate locally persistent or recurrent disease at the original site, requiring salvage surgery to achieve a definitive cure. Patients experiencing treatment failure have a relatively poor prognosis. A retrospective analysis was conducted consisting of 124 patients with early stage (T1 -T2, N0) laryngeal squamous cell carcinoma. In total, 62 patients who failed radiotherapy were matched for T stage, laryngeal subsite and smoking history to a group of 62 patients successfully cured by radiotherapy. Using immunohistochemistry the groups were compared for expression of apoptotic proteins: bcl-2, bcl-X L , bax, bak and survivin. Radioresistant laryngeal cancer was associated with bcl-2 (Po0.001) and bcl-X L (P ¼ 0.005) expression and loss of bax expression (P ¼ 0.012) in pretreatment biopsies. Bcl-2 has an accuracy of 71% in predicting radiotherapy outcome. The association between expression of bcl-2, bcl-X L and bax with radioresistant cancer suggests a potential mechanism by which cancer cells avoid the destructive effects of radiotherapy. Predicting radioresistance, using bcl-2, would allow the clinician to recommend conservative laryngeal surgery as an alternative first line treatment to radiotherapy.

A total of 45 primary head and neck squamous cell carcinomas were analysed by comparative genomic hybridisation to identify regions of chromosomal deletion and gain. Multiple regions of copy number aberration were identified including gains affecting chromosomes 3q, 8q, 5p, 7q, 12p and 11q and deletion of material from chromosomes 3p, 11q, 4p, 5q, 8p, 10q, 13q and 21. KaplanMeier survival analysis revealed significant correlations between gain of 3q25 -27 and deletion of 22q with reduced disease-specific survival. In addition, gain of 17q and 20q, deletion of 19p and 22q and amplification of 11q13 were significantly associated with reduced disease-free survival. A Cox proportional hazards regression model identified deletion of 22q as an independent prognostic marker. The data presented here provide further evidence that the creation of a genetically based tumour classification system will soon be possible, complementing current histopathological characterisation.

Information from the genetic analysis of head and neck cancer has grown enormously in the last 20 years. The advent of high-resolution genetic analysis techniques such as microarray technology will further expand this field in the future. Here we review the data on chromosomal aberrations of head and neck squamous cell carcinoma, focusing on the data generated by comparative genomic hybridization analysis, and suggest how such findings will be taken forward over the next decade. With the search engine PUBMED, the key words "comparative genomic hybridisation," "head and neck," "oral," "hypopharyngeal," "laryngeal," and "squamous cell carcinoma" were used. Publications unavailable in English were excluded.

The outcome for patients with head and neck squamous cell carcinoma remains poor, despite improvements in diagnosis and treatment over the past three decades. This has triggered great interest in the genetic events that underpin the aetiology and clinical behaviour of this group of cancers. As a result, the genetic profile for head and neck squamous cell carcinomas at different sub-sites has been relatively well characterised at the chromosomal level. Various studies have shown links between specific aberrations in head and neck squamous cell carcinoma and clinical outcome, e.g. loss of heterozygosity at 2q and 18q is commonly associated with poor prognosis, and loss of heterozygosity at 9p21 is associated with recurrence. However, there is as yet no significant clinical application of this genetic knowledge as regards the screening, diagnosis or treatment of head and neck squamous cell carcinoma. Here, we summarise the current state of knowledge, and highlight the most promising areas of research that may facilitate the translation of genetic data into clinical benefit.

Survival from head and neck squamous cell carcinoma (HNSCC) has remained static for the last 20 years. The development of lymph node metastasis (LNM) significantly reduces the 5-year survival rate, thus the ability to identify tumours with the potential to metastasise would allow more aggressive treatment regimes to be directed at these patients regardless of negative clinical and radiological findings at the time of presentation. Comparative genomic hybridisation (CGH) can identify chromosomal aberrations that may lead to metastasis. DNA from 23-paired specimens of primary tumour (PT) and LNM were analysed. Nonrandom copy number changes were identified in all paired samples. Similar numbers of aberrations were identified on PT and LNM samples. The most common aberrations were 3q (90%), 8q (65%), 1q (50%), 5p (43%), 2q (41%) and 11q (41%) and deletions 3p (57%), 1p (54%), 4p (48%), 13q (48%), 11q (41%) and 10q (37%). A number of differences were also detected. No aberration was found to be preferentially associated with the LNM, although gains on 6q (48 vs 22%) and 22q (26 vs 9%) were found at higher frequencies. Clonality studies demonstrated that LNM develop from the dominant population of cells in the PT. These results were compared with two similar publications. No combination of chromosomal aberrations, as detected by CGH, was associated with metastatic progression in HNSCC.

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