Identification of PAK Gene Fusions in an Ovarian and a Testicular Serous Carcinoma.

This report describes two unique gonadal serous carcinomas, one low-grade serous carcinoma (LGSC) of the ovary and one serous carcinoma of the scrotum each harboring novel PAK gene fusions. The first patient with ovarian LGSC was identified to have a PTPRM::PAK1 fusion, identifying PTPRM as a novel fusion partner for PAK1. The second patient with high-grade papillary serous carcinoma of the scrotum contained a DLG1::PAK2 fusion. Neither fusion was detected by DNA next-generation sequencing (NGS), highlighting the importance of RNA-based methodologies in identifying gene fusions. Overexpression of PAK1 and PAK2 has been reported in ovarian malignancies, correlating with tumor progression and reduced patient survival, while the significance of the unique fusions reported here warrants further consideration in relation to tumorigenesis and clinical implications.