050-FISH技术在临床中的应用（修订版）课件.pptVIP

. . . . . . . . . . . . ARMS is an aggressive tumors, with a median survival of fewer than 9 months and virtually all patients died of their disease within 4 years of diagnosis from regional nodal and distant metastases to the lungs, pancreas, bones, heart, adrenal glands, and other visceral organs. The probe is used for differential diagnosis of alveolar rhabdomyosarcoma (poor prognosis) from embryonal rhabdomyosarcoma (good prognosis). ? Detection of FOXO1 gene break-apart by FISH is a simple and reliable assay, which can be consistently performed on small, formalin-fixed, and paraffin-embedded tissue samples. Vysis FKHR DC BA Rearrangement Probe Vysis FOXO1 Break Apart FISH Probe Kit In alveolar rhabdomyosarcomas, 70% of ARMS harbor the translocation t(2;13)(q35:q14), which fuses the 5 end of PAX3 with the 3 end of the FOXO1A gene. An additional 10% of ARMS are associated with fusion of PAX7 to the FOXO1A gene. The remaining 20% of ARMS do not have these fusion genes detectable by routine RT-PCR and comprise cases with a very low expression of a fusion gene, a rare variant fusion, or are true fusion negative cases. FISH using a break-apart probe identifies rearrangement of the FOXO1A gene [35, 36]. Karyotype analysis typically reveals either t(2;13) (q35;q14) PAX3-FOXO1A or t(1;13)(p36;q14) PAX7-FOXO1A. The latter is less common but is associated with a better prognosis. ARMS tend to have a poor prognosis overall, especially when presenting with disseminated disease, so genetic testing may be not relevant in stage IV patients. Testing is most useful when the histologic features are not classic (e.g. mixed alveolar and embryonal patterns). * . . The probe is used for confirming the diagnosis of Ewing sarcoma, which is defined by the presence of non-random translocation involving EWS gene on 22q12 with one of the members of ETS family of transcription factors. ? FISH is regarded as the technique of choice in confirming the presence of EWS/ETS translocation bec