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MYB rearrangement and immunohistochemical expression in adenomyoepithelioma of the breast: a comparison with adenoid cystic carcinoma
Author(s) -
Baraban Ezra,
Zhang Paul J,
Jaffer Shabnam,
Lubin Daniel,
Feldman Michael,
Bleiweiss Ira J,
Nayak Anupma
Publication year - 2018
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.13708
Subject(s) - myb , adenoid cystic carcinoma , immunohistochemistry , pathology , breast carcinoma , biology , cancer research , gene expression , carcinoma , medicine , gene , breast cancer , cancer , genetics
Aims Adenomyoepithelioma ( AME ) and adenoid cystic carcinoma ( ACC ) of the breast have been noted to occur simultaneously, raising the possibility that AME may represent a related or precursor lesion to ACC . ACC frequently harbours genetic rearrangement of the MYB gene. We sought to clarify the relationship between AME and ACC by comparing their rates of MYB expression by IHC and MYB rearrangement by FISH . Methods and results IHC and FISH for MYB rearrangement were performed on paraffin‐embedded sections of 11 breast ACC s, 11 non‐breast ACC s and 11 breast‐ AME s. Using FISH , five of eight (63%) interpretable breast ACC s demonstrated MYB gene rearrangement. Nine of 11 (81%) breast ACC s demonstrated MYB expression (range = 20–95%). Of the three FISH ‐negative breast ACC s, two were solid variant and demonstrated strong MYB expression by IHC . Of the 10 interpretable non‐breast ACC s, six showed MYB rearrangement, all of which were conventional type. Nine of these 11 (81%) cases showed MYB immunoexpression (range = 10–90%), including three solid‐variant cases which were negative by FISH . No MYB rearrangements were detected by FISH in 10 interpretable AME s. However, three of 11 cases (27%) showed weak to moderate MYB expression by IHC (range = 10–40%). Conclusions Our results indicate that AME s do not harbour MYB gene rearrangement. IHC for MYB may be helpful in diagnosing FISH ‐negative cases of ACC , particularly the diagnostically more difficult solid variants. However, weak to moderate MYB expression in a subset of AME s highlights not only a potential diagnostic pitfall, but also shared pathophysiology with ACC worth investigating further at the genomic level.