HER-2/neu alterations in non-small cell lung cancer: A comprehensive evaluation by fluorescence in situ hybridization and immunohistochemistry

Aim: The molecular relationships of protein overexpression and HER-2/neu gene amplification in lung cancers are not clearly defined. The aim of the study is to evaluate HER-2/neu changes in non-small cell lung cancer with in situ hybridization and immunohistochemistry, to compare the effectiveness of both methods and to examine the influence of HER-2/neu gene and protein level alterations on prognosis. Material and Methods: HER-2/neu alterations were analyzed with fluorescence in situ hybridization and immunohistochemistry in 24 patients with non-small cell lung cancer. Results: Of 24 patients, 13 (54%) were found immunohistochemistry (IHC) positive, on the other hand 24 (100%) were found fluorescence in situ hybridization (FISH) negative. Balanced trisomy was detected in 23 out of FISH negative cases and balanced quadrisomy was detected in one case. Our study has revealed that overexpression of HER-2/neu protein is not associated with real gene amplification. No significant correlation was detected between HER-2/neu overexpression with amplification, and prognosis of non-small cell lung cancer. Conclusion: No correlation is present between fluorescence in situ hybridization and immunohistochemistry results. HER-2/neu alterations are present in non-small cell lung cancers. Therefore, HER-2/neu overexpression may be associated with transcriptional mechanisms rather than gene amplification.