The 17q12-q21 amplicon: Her2 and topoisomerase-IIalpha and their importance to the biology of solid tumours.
ABSTRACT Her2 and topoisomerase-IIalpha (T2A) gene amplification are separate events, although the latter is more frequently seen in Her2 amplified (34-90%) than in Her2 non-amplified (5-10%) tumours. There is a better correlation between Her2 amplification and protein overexpression in breast cancer (BC) than in other tumour types. This marker is also considered a powerful prognostic factor in BC, with similar data emerging in other solid tumours such as bladder, ovarian, endometrial, gastro-oesophageal and non-small cell lung cancer. Her2 amplification and/or overexpression are highly predictive of response to HER2-targeted compounds such as trastuzumab and lapatinib but have been inconsistent predictors of response to cytotoxic chemotherapy. There is also evidence that these tumours are relatively resistant to anti-oestrogen therapy (tamoxifen) but not to oestrogen deprivation (e.g. with aromatase inhibitors). T2A aberrations are uncommon events in solid tumours, with an overall prevalence of approximately 10%. T2A amplification has shown inconsistent correlation with T2A protein expression in preclinical and clinical studies, mainly because non-genetic events such as proliferation rate can also affect protein expression. Expression of T2A protein has not been shown to reliably predict response to T2A inhibitors, despite the fact that this enzyme is the direct target for these compounds. In BC, T2A amplification appears to be a good predictor of response to anthracyclines, but these data are still in the process of validation. The significance of T2A deletions is currently under investigation, but contrary to what was previously thought, it may also predict benefit from treatment with T2A inhibitors. The prognostic significance of T2A aberrations is currently unknown.
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ABSTRACT: The c-erbB-2 protein is overexpressed in 7% of gastric cancer cases, suggesting that anti-c-erbB-2 antibody therapy (trastuzumab; Herceptin) could be used. We report here a 28-year-old woman with metastatic gastric cancer overexpressing c-erbB-2 (3 + strong membrane staining on immunohistochemistry) who was treated with trastuzumab in combination with chemotherapy. A complete response was obtained with a combination of trastuzumab and oxaliplatin and was maintained with trastuzumab alone for 18 months. The patient relapsed and chemotherapy (capecitabine, docetaxel) was combined with the anti-c-erbB-2 antibody. The patient survived for 4 years with metastatic disease controlled for 2 years by immunochemotherapy. We conclude that the combination of trastuzumab and chemotherapy is efficient in the treatment of metastatic gastric carcinoma with overexpression of the c-erbB-2 protein.Gastric Cancer 02/2005; 8(4):249-52. · 3.99 Impact Factor
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ABSTRACT: Genetic changes underlie tumor progression and may lead to cancer-specific expression of critical genes. Over 1100 publications have described the use of comparative genomic hybridization (CGH) to analyze the pattern of copy number alterations in cancer, but very few of the genes affected are known. Here, we performed high-resolution CGH analysis on cDNA microarrays in breast cancer and directly compared copy number and mRNA expression levels of 13,824 genes to quantitate the impact of genomic changes on gene expression. We identified and mapped the boundaries of 24 independent amplicons, ranging in size from 0.2 to 12 Mb. Throughout the genome, both high- and low-level copy number changes had a substantial impact on gene expression, with 44% of the highly amplified genes showing overexpression and 10.5% of the highly overexpressed genes being amplified. Statistical analysis with random permutation tests identified 270 genes whose expression levels across 14 samples were systematically attributable to gene amplification. These included most previously described amplified genes in breast cancer and many novel targets for genomic alterations, including the HOXB7 gene, the presence of which in a novel amplicon at 17q21.3 was validated in 10.2% of primary breast cancers and associated with poor patient prognosis. In conclusion, CGH on cDNA microarrays revealed hundreds of novel genes whose overexpression is attributable to gene amplification. These genes may provide insights to the clonal evolution and progression of breast cancer and highlight promising therapeutic targets.Cancer Research 12/2002; 62(21):6240-5. · 8.65 Impact Factor
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ABSTRACT: Systemic therapy of metastatic endometrial cancer is relatively ineffective. Response rates to chemotherapy and hormonal therapy in published studies range from 11% to 57%, but most responses are partial and of limited duration. In this case, we present a 76-year-old woman with stage IIIA endometrial adenocarcinoma who was initially treated with surgery and pelvic radiation. She developed multiple pulmonary metastases. She was treated with weekly paclitaxel chemotherapy. Immunostaining revealed that the primary endometrial cancer overexpressed HER-2/neu. Trastuzumab was added to the regimen, and a dramatic partial response was achieved. After a second pulmonary relapse following discontinuation of prior therapy, she was again successfully treated with trastuzumab in combination with paclitaxel and then docetaxel. Therefore, trastuzumab may be a useful adjuvant to taxane-based chemotherapy in some patients with metastatic endometrial cancers that overexpress HER-2/neu.International Journal of Gynecological Cancer 04/2006; 16(3):1370-3. · 1.94 Impact Factor