Analysis of the distribution and frequency of trisomy 7 in vivo in synoviafrom patients with osteoarthritis and pigmented villonodular synovitis

Osteoarthritis (OA) and pigmented villonodular synovitis (PVNS) are disorde rs associated with trisomy 7. The aim of the present study was to determine the frequency and distribution of the cells with +7 in vivo by analyzing s ections of paraffin-embedded synovia from patients affected by OA, PVNS, ot her forms of synovitis [hemorragic synovitis (HS) and chronic synovitis (CS )], and from individuals without joint disease. Fluorescence in situ hybrid ization (FISH), using a centromeric probe for chromosome 7, showed that the mean frequency of trisomic nuclei in 5-mum sections was highest in PVNS (9 .0%), followed by CS (5.9%), OA (5.6%), and HS (4.6%), whereas trisomic nuc lei were rare (0.7%) in normal tissue. When 8-mum sections were studied, th e frequencies of trisomic cells in OA and control synovia increased to 6.7% and 1.5%, respectively. Trisomic nuclei were found in all cases, including those for which cytogenetic analysis of short-term cultures had not disclo sed any trisomic cells. Overall, the trisomic cells were scattered within t he tissue. However, small clusters of cells with +7 were found in three cas es. By hematoxylin-eosin staining of the slides used for FISH analysis it c ould be shown that the clustered trisomic cells were proliferating synovioc ytes within villous extensions of the synovial membrane. (C) 2001 Elsevier Science Inc. All rights reserved.