Molecular alterations of monophasic synovial sarcoma: loss of chromosome 3p does not alter RASSF1 and MLH1 transcriptional activity
L. Pazzaglia1, M.S. Benassi1, P. Ragazzini1, G. Gamberi1, F. Ponticelli1, A. Chiechi1, C.M. Hattinger1, L. Morandi4, M. Alberghini2, L. Zanella2, P. Picci1 and M. Mercuri3
1Laboratory of Oncologic Research, 2Department of Pathology and 35th Orthopaedic Division, Rizzoli Orthopaedic Institute, Bologna, Italy and 4Department of Pathology, Bellaria Hospital, Bologna, Italy
Offprint request to: Maria Serena Benassi, Oncologic Research Laboratory, Istituti Ortopedici Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy. e-mail: mariaserena.benassi@ior.it
Summary. Differential diagnosis of monophasic synovial sarcoma requires the detection of specific biological markers. In this study we evaluated the presence of molecular alterations in 15 monophasic synovial sarcomas. Multiple changes affecting chromosome arms were detected by CGH-array in all microdissected cases available, and an association between gain or loss of specific regions harbouring cancer progression-associated genes and aneuploid status was found. The most frequent alteration was loss of 3p including 3p21.3-p23 region that, however, did not involve the promoter regions of the corresponding genes, RASSF1 and MLH1. Using Real-Time PCR, mRNA levels of both resulted moderately high compared to normal tissue; however, the weak to absent protein expression suggests RASSF1 and MLH1 post-transcription deregulation. Moreover, immuno-histochemical analysis revealed that both mesenchymal and epithelial antigens were present in diploid tumours. These findings confirm the genetic complexity of monophasic synovial sarcoma and underline the need to integrate different analyses for a better knowledge of this tumour, essential to investigate new diagnostic and prognostic markers. Histol Histopatol 21, 187-195 (2006)
Key words: Synovial sarcoma, Laser capture microdissection, CGH-microarray, Real-Time PCR, Gene expression
DOI: 10.14670/HH-21.187