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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: PURPOSE, MATERIEL AND METHODS, RESULTS. Meshes: Adult, Aged, Aged, 80 and over, Breast Neoplasms, Carcinoma, Ductal, Breast, Chromosomes, Human, Pair 8, Combined Modality Therapy, DNA, Neoplasm, Diagnosis, Differential, Female, Gene Amplification, Genes, myc, Hemangiosarcoma, Humans, In Situ Hybridization, Fluorescence, Interphase, Lymph Node Excision, Mastectomy, Middle Aged, Neoplasms, Radiation-Induced, Neoplasms, Second Primary, Radioisotope Teletherapy.
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Can c-myc amplification reliably discriminate postradiation from primary angiosarcoma of the breast? Context: Breast angiosarcomas are rare vascular malignancies that arise secondary to irradiation or de novo as primary tumours. The aim of this study is to know whether c-myc amplification can reliably discriminate these two entities. Forty-seven patients treated for breast angiosarcomas were studied. Thirty-two patients were diagnosed with postradiation angiosarcomas after breast cancer treatment and 15 patients with primary angiosarcomas. Interphase fluorescence in situ hybridization (FISH) was performed by hybridization of probes covering C-MYC (chromosome 8q24.21) and CEP8 on tissue sections. Amplification (5- to 20-fold) of the c-myc oncogene was found in all breast radiation-induced angiosarcomas (32 tumours) but in none of the 15 primary angiosarcomas except one (7%).
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This study reinforces that there are true pathogenetic differences between the two types of breast angiosarcomas which are morphologically indistinguishable. These data point the pathways preferentially involved in the pathogenesis of post radiation angiosarcomas of the breast and may provide the basis for an additional targeted therapy.