Expression patterns for Bcl-2, EMA, β-catenin, E-cadherin, PAX8, and MIB1 in thymomas. Mod Pathol 2021 Oct;34(10):1831-1838
Date
06/18/2021Pubmed ID
34135467DOI
10.1038/s41379-021-00839-1Scopus ID
2-s2.0-85108081360 (requires institutional sign-in at Scopus site) 7 CitationsAbstract
The expression of immunohistochemical markers has been extensively investigated in thymomas to assist in the differential diagnosis. We have studied six select markers to determine their utility in the evaluation of these tumors. A series of 126 thymomas including 33 type A, 27 type AB, 20 type B1, 22 type B2, and 24 type B3, were examined utilizing a tissue microarray (TMA) technique with antibodies to e-cadherin, β-catenin, PAX8, bcl-2, EMA, and MIB-1. Keratin AE1/AE3 and p63 were used for quality control. A significant finding was strong and consistent positivity for bcl-2 in type A (90%) and type AB (88.8%) thymoma, while 100% of B1, B2, and B3 were negative. The distribution of e-cadherin and β-catenin was not useful for differential diagnosis. E-cadherin and β-catenin were expressed in a high proportion of all the tumors (92-100%), except for B2 thymoma which showed only 45% expression. A significant increase in the expression of the MIB-1 proliferation marker (mean: 12.8% nuclear positivity) was also observed in B3 thymoma compared with the other histologic types. Statistical significance was confirmed using Kruskal's non-parameterized test for distribution. EMA was generally negative except for spindle cells in the fibrous septa in types A and AB thymoma. PAX8 showed less consistent nuclear staining than p63 and was only widely expressed in 55.7% of cases. Bcl-2 may serve as a useful marker to separate spindle cell thymomas (Type A and AB) from the other types, and the MIB1 proliferation index may be of use to differentiate type B2 from type B3 thymoma.
Author List
Suster D, Miller JA, Pihan G, Mackinnon AC, Suster SAuthor
James Adam Miller MD, MPH Assistant Professor in the Pathology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Biomarkers, TumorCadherins
Diagnosis, Differential
E2F6 Transcription Factor
Humans
Ki-67 Antigen
PAX8 Transcription Factor
Proto-Oncogene Proteins c-bcl-2
Thymoma
Thymus Neoplasms
beta Catenin