Revisiting Chordoma With Brachyury, a "New Age'' Marker Analysis of a Validation Study on 51 Cases
Chordoma is a rare, notochordal tumor with a characteristic histomorphology and immunohistochemical profile. At times, it presents a diagnostic challenge, especially in small biopsies. Brachyury, a nuclear transcription factor, is a recently described immunohistochemical marker for diagnosing chordomas.
To study the sensitivity and specificity of brachyury in diagnosing chordomas by comparing its expression in axial chordomas with nonchordomatous tumors.
Fifty-one axial chordomas, accessioned during a 10-year period, and 58 nonchordomatous tumors were subjected to brachyury staining by immunohistochemistry.
The 51 chordomas occurred in 36 men and 15 women. Sitewise, 34 cases (66.7%) occurred in the sacrococcyx, 9 (17.6%) in the spine, and 8 (15.7%) in the skull base. Histologically, 34 cases (66.7%) were classical chordomas, 13 cases (25.5%) had a dominant chondroid component, and 2 cases each (3.9%) were chondroid chordomas and dedifferentiated chordomas, respectively. Brachyury staining was positive in 46 of the 51 chordomas (90.2%) and negative in all 58 nonchordomatous tumors. The dedifferentiated area in 2 chordomas was negative for brachyury staining. Fourteen of 15 chordomas with chondroid component showed positive brachyury staining. Immunohistochemical expression of other markers, included cytokeratin (positive in 23 of 23 cases; 100%), epithelial membrane antigen (positive in 22 of 22 cases; 100%) and S100 protein (positive in 18 of 21 cases; 85.7%).
Exclusive brachyury expression in more than 90% of chordomas indicates its value as a unique, specific marker with other sensitive markers like cytokeratin, epithelial membrane antigen, and/or S100 protein in substantiating a diagnosis of chordoma, including on small biopsies.
Available from: Prof. Dr. Giovanni Tuccari
- "HBL may rarely occur in the kidney as a sporadic entity. At present, less than ten cases have been reported in the literature [8, 11, 33, 56]. Due to its rarity, primary renal HBL is usually not considered in the differential diagnosis of renal tumours . "
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ABSTRACT: Brachyury is a transcription factor which is required for posterior mesoderm formation and differentiation as well as for notochord development during embryogenesis. Due to its expression in the neoplastic cells of chordoma, a malignant tumour deriving from notochordal remnants, but not in tumors showing a similar histology, brachyury has been proposed as a diagnostic marker of this neoplasia. Though commonly considered a hallmark of chordoma, the expression of brachyury has been also documented in the stromal cells of hemangioblastoma (HBL), a slow growing tumor which may involve the central nervous system (CNS) and, rarely, the kidney. Herein we review the role of brachyury immunohistochemical detection in the identification and differential diagnosis of chordoma and HBL towards histological mimickers and suggest that brachyury is added to the panel of immunohistochemical markers for the recognition of HBL in routinary practice, principally in unusual sites.
Available from: Seth D Goldstein
- "Although no further tissue is available from the primary resection, histological and immunohistochemical analysis reveals similarities between the xenograft and tissue from the metastatic relapse. We demonstrated brachyury expression, thought to be a specific marker for chordoma , in our xenograft both by PCR and by immunohistochemistry. Brachyury is mislocalized to the cytoplasm in our xenograft, and this aberrant expression is also seen in pathologic sections from the relapsed tumor. We demonstrated cytoplasmic brachyury staining in the xenograft using 2 distinct antibodies, but were able to demonstrate nuclear localization of brachyury in a sample of classical chordoma using these antibodies, making it highly unlikely that this finding is a technical artifact. "
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ABSTRACT: Chordoma is a rare primary bone malignancy that arises in the skull base, spine and sacrum and originates from remnants of the notochord. These tumors are typically resistant to conventional chemotherapy, and to date there are no FDA-approved agents to treat chordoma. The lack of in vivo models of chordoma has impeded the development of new therapies for this tumor. Primary tumor from a sacral chordoma was xenografted into NOD/SCID/IL-2R γ-null mice. The xenograft is serially transplantable and was characterized by both gene expression analysis and whole genome SNP genotyping. The NIH Chemical Genomics Center performed high-throughput screening of 2,816 compounds using two established chordoma cell lines, U-CH1 and U-CH2B. The screen yielded several compounds that showed activity and two, sunitinib and bortezomib, were tested in the xenograft. Both agents slowed the growth of the xenograft tumor. Sensitivity to an inhibitor of IκB, as well as inhibition of an NF-κB gene expression signature demonstrated the importance of NF-κB signaling for chordoma growth. This serially transplantable chordoma xenograft is thus a practical model to study chordomas and perform in vivo preclinical drug testing.
Available from: Yutaka Nibu
- "However, the immunoreactivity for S-100, which is shared among chordomas and chondrosarcomas, made the assignment of tumors to either category quite challenging. This was particularly true when only small biopsies could be obtained, as in the case of clival chordomas (e.g., ). Another genetic marker of chordomas is chondroitin sulfate proteoglycan 4 (CSPG4), which has also been targeted for immunotherapy; however, this antigen is expressed only by a fraction (~62%) of these tumors  and could therefore produce false negative diagnoses. "
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ABSTRACT: Chordoma is a rare, but often malignant, bone cancer that preferentially affects the axial skeleton and the skull base. These tumors are both sporadic and hereditary and appear to occur more frequently after the fourth decade of life; however, modern technologies have increased the detection of pediatric chordomas. Chordomas originate from remnants of the notochord, the main embryonic axial structure that precedes the backbone, and share with notochord cells both histological features and the expression of characteristic genes. One such gene is Brachyury, which encodes for a sequence-specific transcription factor. Known for decades as a main regulator of notochord formation, Brachyury has recently gained interest as a biomarker and causative agent of chordoma, and therefore as a promising therapeutic target. Here, we review the main characteristics of chordoma, the molecular markers, and the clinical approaches currently available for the early detection and possible treatment of this cancer. In particular, we report on the current knowledge of the role of Brachyury and of its possible mechanisms of action in both notochord formation and chordoma etiogenesis.
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