Introduction: The human epidermal growth factor receptor ( her-2/ neu) protooncogene encodes a membrane tyrosine kinase with homology to the epidermal growth factor receptor (EGFR). Amplification and protein overexpression have been identified in various solid tumors and a significant association with poor clinical outcome was reported. This investigation was performed to assess the frequency of her-2/ neu overexpression and to compare these results with clinical outcome in OSCC.
Material and methods: Archival biopsy specimens from 97 untreated OSCCs were evaluated using a polyclonal antibody A0485 (Dako). Only membrane staining intensity and pattern were evaluated according to the guidelines of the clinical trial assay recommendations (0-3+) for breast carcinoma. Score 0 and 1+ were interpreted as negative for HER-2/NEU protein overexpression and 2+ and 3+ as positive. FISH analysis with directly labeled probes for her-2/ neu and chromosome 17 was performed on the same specimens. The ratio between her-2/ neu and chromosome 17 signals was calculated after selection of 20-40 non-overlapping tumor cells. The tumor was considered amplified if the ratio was above 2.
Results: In 11 out of 97 biopsies (11.3%) membranous overexpression (score 2+ and 3+) of her-2/ neu was shown by immunohistochemistry. FISH analysis in 42 cases revealed amplification in 14 cases. Concordance between immunohistochemistry and FISH was found in 86%. Clinical-pathological data as well as survival revealed no correlation with her-2/ neu status.
Discussion: In spite of missing correlation between survival and her-2/ neu overexpression in our study, the predictive value of the her-2/ neu protooncogene in adjuvant therapy in OSCC needs further investigation.