부산대학교 도서관

Infantile fibrosarcoma and congenital mesoblastic nephroma are tumors of infancy traditionally associated with the ETV6–NTRK3gene fusion. However, a number of case reports have identified variant fusions in these tumors. In order to assess the frequency of variant NTRK3fusions, and in particular whether the recently identified EML4–NTRK3fusion is recurrent, 63 archival cases of infantile fibrosarcoma, congenital mesoblastic nephroma, mammary analog secretory carcinoma and secretory breast carcinoma (tumor types that are known to carry recurrent ETV6–NTRK3fusions) were tested with NTRK3break-apart FISH, EML4–NTRK3dual fusion FISH, and targeted RNA sequencing. The EML4–NTRK3fusion was identified in two cases of infantile fibrosarcoma (one of which was previously described), and in one case of congenital mesoblastic nephroma, demonstrating that the EML4–NTRK3fusion is a recurrent genetic event in these related tumors. The growing spectrum of gene fusions associated with infantile fibrosarcoma and congenital mesoblastic nephroma along with the recent availability of targeted therapies directed toward inhibition of NTRK signaling argue for alternate testing strategies beyond ETV6break-apart FISH. The use of either NTRK3FISH or next-generation sequencing will expand the number of cases in which an oncogenic fusion is identified and facilitate optimal diagnosis and treatment for patients.