[1042] FISH for Diagnosis of Endometrial Stromal Sarcoma

R Ali, CH Lee, A Zayed, A Dastranj, A Elomami, E Mehl, J Senz, CB Gilks, D Huntsman. Vancouver General Hospital, Vancouver, BC, Canada; BC Cancer Agency, Vancouver, BC, Canada; Genetic Pathology Evaluation Centre (GPEC), Vancouver, BC, Canada; Tabriz University of Medical Science, Tabriz, Islamic Republic of Iran

Background: Endometrial stromal sarcoma (ESS) account for 20% of all uterine sarcomas. t(7;17) (p15;q21) that results in the fusion gene JAZF1-JJAZ1 represents the most common type of translocations in ESS. This rearrangement has been demonstrated in about 50% of ESS studied to date and it has not been found in other uterine sarcomas. More recently, other types of translocations have been reported in ESS including JAZF1-PHF1 and EPC1-PHF1.
Design: The aim of our study is to determine the frequency of JAZF1-JJAZ1, JAZF1-PHF1 and EPC1-PHF1 in ESS and morphologically similar tumors by fluorescence in situ hybridization (FISH). A total of 58 formalin-fixed paraffin-embedded tissue samples were studied by FISH. These included 23 ESS, 6 undifferentiated endometrial sarcomas (UES), 16 adenosarcomas, 2 malignant mixed Mullerian tumors (MMMT), 2 uterine tumors resembling ovarian sex cord tumors (UTROSCT), 1 cellular leiomyoma, 1 leiomyosarcoma, and 7 polypoid endometriosis. For FISH, a combination of break-apart and fusion probe sets was used to interrogate for the presence of the different gene rearrangements/fusions involving JAZF1, JJAZ1, EPC1, PHF1.
Results: Of the 21 cases of ESS with interpretable FISH results, a total of 13 (62%) ESS showed evidence for gene rearrangements, with 7 (33%) cases showing JAZF1/JJAZ1 fusion, 3 (14%) cases showing JAZF1/PHF1 fusion, and 1 case showing EPC1/PHF1 fusion. In addition, one ESS demonstrated only JAZF1 rearrangement and another demonstrated only PHF1 rearrangement, with no fusion partner identified by the current probe sets. No rearrangements were present in the 8 remaining ESS and other non-ESS cases examined.
Conclusions: Our study provides further confirmation for the specificity of these genetic rearrangement events for ESS and shows that FISH assays with multiple combination probe sets for JAZF1, JJAZ1, EPC1, and PHF1 can achieve increased sensitivity (62%) for the detection of ESS. However, further studies to fully characterize the genetic spectrum of ESS will be necessary to improve the sensitivity of these ancillary diagnostic methods.
Category: Gynecologic & Obstetrics

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 151, Wednesday Morning


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