PDGF-A, PDGF-Rbeta, TGFbeta3 and bone morphogenic protein-4 in desmoplastic small round cell tumors with EWS-WT1 gene fusion product and their role in stromal desmoplasia: an immunohistochemical study.

Abstract

Histologically, desmoplastic small round cell tumor is composed of the characteristic neoplastic small round cells with divergent differentiation, and distinct desmoplastic stroma. Genetically, the tumor shows a characteristic 11;22 translocation, involving the EWS gene on chromosome 22 and the WT1gene on chromosome 11 to produce an EWS-WT1 fusion gene which generates a chimeric protein functioning as a novel transcription factor that activates expression of target genes such as PDGF-A. Expression of PDGF-A, a potent growth factor for fibroblasts, has been detected in desmoplastic small round cell tumors and has been linked to the characteristic desmoplasia in these tumors. Bone morphogenic proteins, which are members of the TGFbeta superfamily play a complex role in regulating cell growth and differentiation and bone formation but have not been evaluated in desmoplastic small round cell tumors. In all, 24 desmoplastic small round cell tumors with EWS-WT1 fusion product confirmed by RT-PCR analysis were evaluated for expression of PDGF-A, PDGF-Rbeta, TGFbeta3 and bone morphogenic protein-4 by standard immunohistochemical methods with antigen retrieval on paraffin sections. Immunoreactivity was evaluated semiquantitively. Tumor-associated desmoplasia was quantified using a three-tier scale on hematoxylin- and eosin-stained sections. Desmoplastic small round cell tumors showed variable immunoreactivity with TGFbeta3 (21/24), BMP4 (14/21), PDGF-A (19/24) and PDGF-Rbeta (16/22). Less frequently, the stromal cells showed reactivity with TGFbeta3, PDGF-Rbeta and PDGF-A. Tumor-associated desmoplasia was prominent in eight, intermediate in seven and weak in nine cases. There was no correlation between tumor-associated desmoplasia and the markers tested except PDGF-A. In contrast to a previous study, our study showed that the level of PDGF-A expression inversely correlated with tumor-associated desmoplasia. Other targets of the EWS-WT1 transcription factor other than PDGF-A may be directly responsible for the prominent tumor-associated desmoplasia seen in desmoplastic small round cell tumor.

• Authors: Paul J Zhang, John R Goldblum, Bruce R Pawel, Theresa L Pasha, Cyril Fisher, Frederic G Barr
• Journal: Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc (Mod Pathol) Vol. 18 Issue 3 Pg. 382-7 (Mar 2005) ISSN: 0893-3952 [Print] United States
• PMID: 15389255 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• BMP4 protein, human
• Bone Morphogenetic Protein 4
• Bone Morphogenetic Proteins
• EWS1-WT1 fusion protein, human
• Oncogene Proteins, Fusion
• Platelet-Derived Growth Factor
• Proteins
• Transforming Growth Factor beta
• Transforming Growth Factor beta3
• platelet-derived growth factor A
• Receptor, Platelet-Derived Growth Factor beta

Topics

• Abdominal Neoplasms (genetics, metabolism, pathology)
• Bone Morphogenetic Protein 4
• Bone Morphogenetic Proteins (analysis)
• Carcinoma, Small Cell (genetics, metabolism, pathology)
• Gene Expression Regulation, Neoplastic
• Humans
• Immunohistochemistry
• Oncogene Proteins, Fusion (genetics)
• Platelet-Derived Growth Factor (analysis)
• Proteins (analysis)
• Receptor, Platelet-Derived Growth Factor beta (analysis)
• Reverse Transcriptase Polymerase Chain Reaction
• Transforming Growth Factor beta (analysis)
• Transforming Growth Factor beta3