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NKX3.1 immunoreactivity is not identified in mesenchymal chondrosarcoma: a 25‐case cohort study
Author(s) -
Chen Wei,
Hornick Jason L,
Fletcher Christopher D M
Publication year - 2021
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.14231
Subject(s) - immunohistochemistry , pathology , cd99 , polyclonal antibodies , mesenchymal chondrosarcoma , biology , mesenchymal stem cell , medicine , antibody , immunology , vimentin
Aims Mesenchymal chondrosarcoma (MC) is characterised typically by a bimorphic microscopic appearance of islands of a well‐differentiated cartilaginous component, admixed with a primitive small cell component, which commonly expresses CD99 and NKX2.2. Given the variable relative abundance of each component and histological overlap with other small round cell tumours, the diagnosis can be challenging, especially in a limited sample. A distinctive gene fusion between HEY1 (located in 8q21) and NCOA2 (located in 8q13) was identified in MC, but the downstream molecular events are unknown. NKX3.1 (coding gene located in 8p21.1) was recently reported to be expressed in a small number of MC cases. The purpose of this study was to evaluate the potential diagnostic utility of NKX3.1 immunohistochemistry in MC. Methods and results We evaluated sections from 25 cases of MC, including 20 extraskeletal and five osseous. The tumour affected nine females and 16 males, with a median age of 34 years (age range = 7–82 years). Two different rabbit antibodies against NKX3.1 (monoclonal and polyclonal) were used for immunohistochemistry. However, no immunoreactivity was observed with either of the antibodies in all 25 (100%) MC. Conclusions NKX3.1 immunoreactivity was not identified in our cohort. Clonality of the antibody could not explain the negativity.