Clinical application of fluorescence in situ hybridization for chromosome 11q13 analysis in head and neck cancer

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Abstract
Objective: Squamous cell carcinoma of the head and neck (HNSCC) still has one of the lowest 5‐year survival rates. Despite advances in diagnosis, treatment, and research, survival rates have not improved in recent years. This report examines the utility of fluorescence in situ hybridization (FISH) in detecting chromosome 11q13 amplification in HNSCC and in evaluating the correlation between 11q13 amplification and tumor behavior. Study Design: This study used FISH to determine the incidence of 11q13 amplification in 20 HNSCCs and 10 normal controls from the same patients. Tumor touch preparations and paraffin‐embedded tissues from the same patient samples were used for comparative analysis. Both single and dual color FISH was performed. Methods: Repetitive chromosome 11 specific alpha satellite DNA probe and chromosome 11q13 specific probe cyclin D1 were used for the FISH analysis. Results: Experiments revealed amplification of chromosome 11q13 in three fresh touch preparations. FISH on paraffin tissues showed amplification in two additional samples. Intensity of amplification, as high as 20 copies per nucleus, was observed in paraffin preparations, whereas a maximum of only six copies was seen in fresh preparations. Amplification was not detected in any of the normal samples. All five cases with 11q13 amplification had metastases and four of these were from poorly differentiated tumors. In the nonamplified cases, 5 of 15 had metastases and 2 of 15 was poorly differentiated. Conclusions: The present study indicates that FISH is a useful technique for detecting molecular changes such as amplification of chromosome 11q13 in HNSCC. FISH in paraffin preparations allows for accurate measurement of intensity of amplification and makes it possible for the evaluation of a large collection of archival material. The data also suggest that 11q13 amplification is correlated with poorly differentiated tumors and metastasis. Thus FISH has the potential to be a valuable diagnostic/prognostic tool in head and neck cancers. Key Words: Head and neck tumors, FISH, chromosome 11q13.