t(19;22)(q13;q12) Translocation leading to the novel fusion gene EWSR1‐ZNF444 in soft tissue myoepithelial carcinoma

Myoepithelial neoplasms of soft tissue have only recently been acknowledged as a separate diagnostic entity. To know based on histological appearance whether these tumors are benign or malignant is often difficult, and their tumorigenic mechanisms remain poorly understood. We report a myoepithelial carcinoma with an aberrant near-diploid karyotype, 43 approximately 47,XX,add(1)(p34)x2,add(3)(q27)x2,del(12)(q22),+add(18)(p11)x2,del(22)(q11),+r, found in cells cultured from a lung metastasis. The deletion in 22q led us to search by molecular cytogenetic means for possible EWSR1 rearrangements, and eventually a novel chimeric gene consisting of the 5'-end of EWSR1 (22q12) and the 3'-end of ZNF444 (19q13) was found. How the new fusion gene contributes to tumorigenesis is unknown, but the finding of an EWSR1 rearrangement suggests that this, possibly even the EWSR1-ZNF444, is a defining pathogenetic feature of at least a subset of these tumors.