An endometrial stromal sarcoma cell line with the JAZF1/PHF1 chimera

Endometrial stromal sarcomas (ESS) are rare malignancies, accounting for less than 10% of uterine sarcomas. Apart from the chromosomal rearrangement t(7;17)(p15;q21), which leads to the JAZF1/SUZ12 chimera, cytogenetic studies have shown that the chromosome band 6p21 is often rearranged in ESS. The translocation partners involved in the 6p21 rearrangements differ among the tumors, but chromosome 7 is involved in most aberrations. A JAZF1/PHF1 fusion gene was recently found in two tumors showing an exchange between 6p and 7p rearrangement. In the present study, we show that a low-grade ESS cell line carrying a der(7)t(6;7)(p21;p22) also harbors the a JAZF1/PHF1 fusion. In the fusion transcript, exon 3 of JAZF1 was fused with exon 2 of PHF1. At the junction, there was an insertion of 26 nucleotides, originating from intron 3 of JAZF1, thus maintaining an open reading frame of the chimeric transcript. The predicted 684-amino acid JAZF1/PHF1 chimeric protein retained one zinc finger domain from JAZF1 and the two zinc finger domains from PHF1, and its oncogenic mechanism should be similar to that of the JAZF1/SUZ12 protein. The present cell line constitutes an excellent model for further studies on the impact of the JAZF1/PHF1 fusion.