The Role of Immunohistochemistry in Rhabdomyosarcoma Diagnosis Using Tissue Microarray Technology and a Xenograft Model

Abstract

Rhabdomyosarcomas (RMS) may resemble other non-myogenic sarcomas and malignant rhabdoid tumor (MRT). Alveolar rhabdomyosarcoma (ARMS) often harbors a typical translocation, but embryonal rhabdomyosarcoma (ERMS) lacks any specific rearrangement. Histopathology is not always sufficient for an unequivocal diagnosis, necessitating ancillary studies, including immunohistochemistry (IHC). Sixteen genetically tested RMS and two MRT were xenografted and followed in successive passages. Tissue microarrays were constructed including samples from original and xenograft tumors. Desmin, myogenin, CK, EMA, INI1, LSD1, AP2β, fibrillin-2, HMGA2, nestin, and SIRT1 were tested using immunohistochemical staining. Desmin and myogenin were positive in all RMS, and the epithelial markers were negative in almost all RMS. New markers (LSD1, AP2β, HMGA2, Nestin, and SIRT1) were positive in all RMS and MRT. There were no differences in IHC expression between the three RMS subtypes tested except fibrillin-2, which was negative in ARMS. Applying new IHC markers can contribute to RMS diagnosis. Nevertheless, most markers are also expressed in MRT, and further studies are needed to confirm their value against this and other small round cell tumors.

Keywords: :

• rhabdomyosarcoma
• immunohistochemistry
• tissue microarrays
• xenografts

ACKNOWLEDGMENTS

The authors thank David Harrison for the English review and editing.

Declaration of Interest

The authors of the study declare that they have no conflicts of interest and any financial agreements with pharmaceutical or biomedical firms whose products are pertinent to the subject matter dealt within the manuscript. The authors alone are responsible for the content and writing of the article.

This study was funded by contract no.: 018814 (EuroBoNet) from the 6th FP of the EC.