Summary Breast cancer patients who receive radiation therapy or develop chronic lymphedema following axillary dissection can develop secondary mammary angiosarcomas (ASs) and, additionally, atypical ...vascular lesions (AVLs) in the former group. Recently, MYC amplification by fluorescence in situ hybridization (FISH) has been identified in secondary mammary AS but not in AVL and most primary mammary AS as well as AS of other sites. We studied MYC amplification and MYC protein expression in 7 radiation-induced AVLs, 9 secondary mammary ASs, 17 primary mammary ASs, and 20 primary ASs of other sites by FISH analysis and immunohistochemistry. All 9 secondary mammary ASs showed gene amplification and protein expression, whereas neither was found in any of 7 AVLs. No MYC amplification or protein expression was identified in any of the 17 primary mammary ASs. Among primary ASs of other sites, 1 cardiac AS and 1 skin AS showed gene amplification and protein expression. The remaining 18 did not show amplification (90%), but some demonstrated protein expression (39%). We conclude that MYC amplification by FISH is present in secondary mammary AS but not in AVL. We also found MYC amplification in 1 primary skin AS and 1 primary cardiac AS. There was 100% concordance between MYC amplification and protein expression in all AVL, primary mammary AS, and secondary mammary AS, whereas only 65% concordance was found in AS of other sites. MYC protein expression in AS can be helpful in certain diagnostic scenarios in the breast but not in other sites.
Summary Adenoid cystic carcinomas (ACCs) from various anatomical sites harbor a translocation t(6;9)(q22-23;p23-24), resulting in MYB-NFIB gene fusion. This gene fusion is not well studied in mammary ...ACCs, and there are no studies examining this abnormality in solid variant of ACC with basaloid features (SBACC), a high-grade variant thought to behave more aggressively than ACCs with conventional histologic growth. Our aim was to investigate the frequency of MYB-NFIB gene fusion in mammary ACCs with a focus paid to SBACC. MYB rearrangement and MYB-NFIB fusion were assessed by fluorescence in situ hybridization and reverse-transcription polymerase chain reaction, respectively. Histologic features and the presence of MYB rearrangement were correlated with clinical outcome. MYB rearrangement was present in 7 (22.6%) of 31 mammary ACCs (5/15 33.3% ACCs with conventional growth; 2/16 12.5% SBACCs). One patient with conventional ACC developed distant metastasis, and no patients had axillary lymph node involvement by ACC (mean follow-up, 34 months; range, 12-84 months). Two patients with SBACC had axillary lymph node involvement at initial surgery, and 2 additional patients experienced disease recurrence (1 local, 1 distant; mean follow-up, 50 months; range, 9-192 months). MYB-NFIB fusion status did not correlate with clinical outcome in studied patients. We confirm that MYB - NFIB gene fusion is observed in mammary ACCs and that a subset lacks this abnormality. This study is the first to confirm the presence of MYB rearrangement in SBACC. Additional validation with long-term follow-up is needed to determine the relationship, if any, between MYB-NFIB gene fusion and clinical outcome.
Mammary myofibroblastoma is a benign spindle cell tumor that can show variable morphologic patterns and lines of differentiation. Myofibroblastoma belongs to a family of CD34-positive tumors with ...similar morphology that show a deletion of 13q14, which includes RB1 and FOXO1A genes. A subset of these tumors demonstrates distinct smooth muscle differentiation which can be confused with other smooth muscle tumors of the breast, itself constituting a rarified morphological subgroup. We aimed to characterize 4 cases of the leiomyomatous variant of myofibroblastoma arising in the breast by clinicopathological, immunohistochemical, and molecular means. All 4 examples arose in women aged 41–62 years (median, 46.5 years). Tumors ranged in size from 1.7 to 2.5 cm (median, 2.2 cm). Morphologically, all tumors were characterized by bundles of smooth muscle cells with elongated cigar-shaped nuclei and eosinophilic cytoplasm. All four tumors showed diffuse positive staining with desmin, caldesmon, smooth muscle actin (SMA), estrogen receptor (ER), and Bcl-2. CD34 staining was diffusely positive in two cases, weak and patchy in one case, and was negative in one case. Two of four (50%) tumors showed deletion of RB1 by fluorescence in situ hybridization (FISH). Loss of Rb staining was seen in one tumor with RB1 deletion by FISH, while intact Rb staining was observed in one non-deleted case studied. In conclusion, this rare variant of myofibroblastoma is a distinct subgroup of tumors among an already uncommon category of (smooth muscle) breast tumors. Some reported examples of “parenchymal leiomyoma” may represent the leiomyomatous variant of myofibroblastoma.
Summary Aurora kinase A ( AURKA ) gene amplification has been documented in 67% of hormone-naive prostate cancer cases that progress to a highly aggressive variant of castrate-resistant disease, ...clinically referred to as “neuroendocrine” prostate cancer, “small cell” prostate carcinoma, or “anaplastic” prostate cancer. Therefore, AURKA amplification is a potential prognostic biomarker that may help to identify patients with prostate cancer who are at high risk for developing castrate-resistant disease with clinical features of small cell carcinoma. Furthermore, AURKA inhibitors are currently being tested in clinical trials. In a previous study, we found AURKA amplification in 6 cases of prostate cancer with Paneth cell–like cells. This morphologic pattern has been suggested to represent low-grade neuroendocrine differentiation (NED) with generally favorable prognosis. We sought to investigate the frequency of AURKA amplification and the histologic characteristics of prostate cancer with Paneth cell–like NED. Twenty-five cases from 172 prostatectomies were evaluated for the presence of 18 morphologic features and AURKA amplification. Most prostate cancers with Paneth cell–like NED had macronucleoli (92%), basophilic appearance (88%), perineural invasion (72%), and nuclear stratification (76%). The frequency of AURKA amplification was 45%, present throughout the examined tumor nodule including areas without Paneth cell–like cells. When histologically similar cases with and without AURKA amplification were compared, this gene alteration was associated with larger extent of Paneth cell–like NED identified at magnification ×20 ( P = .015), higher percentage of Paneth cell–like NED throughout the tumor nodule ( P = .033), ductal features ( P = .02), and higher overall Gleason grade ( P = .039). AURKA amplification was not associated with age, serum prostate specific antigen, or tumor stage. The high frequency of AURKA amplification (45%) in localized prostate cancer with Paneth cell–like NED and its potential prognostic significance warrant further investigation.
PDF