Distinct Xp11.2 breakpoint regions in synovial sarcoma revealed by metaphase and interphase FISH: Relationship to histologic subtypes

Molecular cytogenetics of bone and soft tissue tumors

“…A ccordingly, a subgroup of tumors show ed a split fluores cent signal w h en hybridized w ith an OATLl-specific YAC, b u t n o t with, an OATL2-specific YAC. The opposite w as observed in th e other subgroup of tum ors, indicating th at the tw o alternative X p ll.2 breakpoints are m utually exclusive [18]. T he subsequent subcloning of one of the YACs [OATLl] re su lted in probes that hybridize to altered restriction fragments in tum or DNAs after Southern blot analysis.…”

“…The use of YAC probes for FISH analy sis on fresh or archival tum or samples has am ply proven its u sefu ln ess in the detection of the translocation an d the lo calizatio n of the X p ll.2 breakpoints, even w h e n com plex rearrangem ents are present [18,31], In addition, the isola tio n and characterization of the SYT and SSX genes has o p en ed u p the possibility of employing a reverse tra n scrip tio n polym erase chain reaction (RT-PCR) assay as a m eans to detect SYT-SSX fusion transcripts and, therefore, to retrieve inform ation from tumors not am enable to cytoge n e tic analysis, By using th e RT-PCR approach, SYT-SSX transcripts have been detected in 70 synovial sarcomas-45 w ith SYT-SSX1 transcripts an d 25 w ith SYT-SSX2 tran scrip ts [22,23,32,33], Both techniques, FISH an d RT-PCR, have also been used to evaluate a possible correlation betw een X p ll.2 breakpoint localization and histological tu m o r (sub) type. Interestingly we found th a t all b ip h asic synovial sarcom as exhibited a break in the OATLl [SSXÍ] region, w hereas m ost tum ors diagnosed as m onophasic w e re found to carry a break in the OATL2 (SSX2) region [18,34]. These latter findings have been corroborated by som e but n o t all reports from other investigators and, as such, m ust await further validation [32,33,35].…”

Distinct Xp11.2 breakpoints in two renal cell carcinomas exhibiting X;autosome translocations

“…All fluorescence in situ hybridization (FISH) procedures on metaphase cells were essentially as described previously (De Leeuw et aL, 1994b). The probes used were: the centromere X-specific alphoid sequence probe pBamXS, the OATL1 YAC #2, and the OATL2 YAC #7.…”

The C terminus of the synovial sarcoma-associated SSX proteins interacts with the LIM homeobox protein LHX4

“…As a result of this translocation, the SS18 gene (previously called SYT) on chromosome 18 is fused to either one of the three closely related SSX genes on the X chromosome, SSX1, SSX2 or SSX4 (Clark et al, 1994;Crew et al, 1995;de Leeuw et al, 1995;Skytting et al, 1999). The occurrence of either SS18-SSX1 or SS18-SSX2 fusions was found to correlate to histologic (de Leeuw et al, 1994) and/or prognostic (Kawai et al, 1998;Ladanyi et al, 2002) parameters, although the latter observation could not be confirmed (Guillou et al, 2004).…”