Does radiation-induced c-MYC amplification initiate breast oncogenesis?

MYC Amplification in Epithelioid Angiosarcoma of the Urinary Bladder and Prostate Following Prostate Radiotherapy: A Case Report with a Novel Molecular Alteration

Epithelioid angiosarcoma is a rare variant of angiosarcoma. Radiation-associated epithelioid angiosarcoma of the urinary bladder and prostate is an exceedingly rare tumor and there are only 8 cases of epithelioid angiosarcoma of the urinary bladder and prostate associated with previous radiotherapy in the literature. To the best of our knowledge, MYC gene amplification has not been previously reported in epithelioid angiosarcoma of the urinary bladder and prostate following radiotherapy, although it is observed in radiation-associated angiosarcoma of other anatomic sites. Here we report the first case of epithelioid angiosarcoma of the urinary bladder and prostate with MYC gene amplification detected by fluorescence in situ hybridization (FISH) analysis in a 70-year-old male patient 10 years after receiving radiation and hormonal therapy for prostate cancer.

Secondary Angiosarcoma With C-MYC Amplification Following Prophylactic Bilateral Mastectomy and Autologous Breast Reconstruction: Report of a Case and Review of the Literature

In this article, we report a very rare case of secondary angiosarcoma in a young woman with no prior history of breast cancer who had bilateral prophylactic mastectomies with autologous reconstruction due to a strong family history of breast cancer and BRCA1 gene variant of uncertain significance. The surgery was complicated by recurrent fat necrosis requiring several excisions and additional reconstruction followed by the development of localized lymphedema and subsequent angiosarcoma in the reconstructed breast 10 years later. The angiosarcoma was high grade with prominent epithelioid features associated with abundant tumor-infiltrating lymphocytes. Amplification of C-MYC locus 8q21.24 was demonstrated by fluorescence in situ hybridization study. We postulate that chronic trauma from several surgeries including tissue hypoxia and impaired lymphatic drainage may have provided a milieu for angiogenesis and mutagenic transformation. Amplification of C-MYC locus 8q21.24 was most likely a strong oncogenic driver of angiosarcoma. To the best of our knowledge, this is the first report of its kind in the literature.

Radiotherapy-associated intra-abdominal angiosarcoma after prostatic adenocarcinoma: Case reports

Angiosarcoma is a rare soft tissue neoplasm, which accounts for <1% of all soft tissue tumours. It has been previously reported that the incidence rate of angiosarcomas increases following radiotherapy. The present study reports two cases of intra-abdominal angiosarcoma associated with previous radiotherapy treatment. To the best of our knowledge, these associations have not been previously described in English literature. The patients aged 71 and 83 years were admitted to the center for abdominal pain and diarrhea. Each patient had previously had treatment with radiotherapy for prostate adenocarcinoma. During their hospitalization, biopsies were obtained and the diagnosis of angiosarcoma was reached. In each patient the tumors had irregular proliferating vascular channels, lined by atypical endothelial cells, which varied from elongated and spindle-shaped to large and plump. Immunocytochemistry revealed that the tumor cells were positive for the cytoplasmic endothelial markers cluster of differentiation (CD)31 and CD34. The recognition of these associations is important and their occurrence in this rare type of neoplasm should not mislead the pathologist and cause a misdiagnosis of the sarcoma.

Mutational landscape of radiation-associated angiosarcoma of the breast

Purpose

Radiation-associated breast angiosarcomas are a rare complication of radiation therapy for breast carcinoma. With relatively little is known about the genetic abnormalities present in these secondary tumors, we examined genomic variation in biospecimens from radiation-associated breast angiosarcomas.

Experimental Design

Patients were identified that had a previous breast cancer diagnosis, received radiation therapy, and developed angiosarcoma in the ipsilateral breast as the earlier cancer. Tumor regions were isolated from archival blocks using subsequent laser capture microdissection. Next generation sequencing was performed using a targeted panel of 160 cancer-related genes. Genomic variants were identified for mutation and trinucleotide-based mutational signature analysis.

Results

44 variants in 34 genes were found in more than two thirds of the cases; this included 12 variants identified as potentially deleterious. Of particular note, the BRCA1 DNA damage response pathway was highly enriched with genetic variation. In a comparison to local recurrences, 14 variants in 11 genes were present in both the primary and recurrent lesions including variants in genes associated with the DNA damage response machinery. Furthermore, the mutational signature analysis shows that a previously defined IR signature is present in almost all of the current samples characterized by predominantly C→T substitutions.

Conclusions

While radiation-associated breast angiosarcomas are relatively uncommon, their prognosis is very poor. These data demonstrate a mutational pattern associated with genes involved in DNA repair. While important in revealing the biology behind these tumors, it may also suggest new treatment strategies that will prove successful.