Abstract

Human uterine leiomyosarcoma (Ut-LMS) is neoplastic malignancy that typically arises in tissues of mesenchymal origin. The identification of novel molecular mechanism leading to human UtLMS formation and the establishment of new therapies has been hampered by several critical points. We earlier reported that mice with a homozygous deficiency for proteasome subunit beta type (PSMB) 9, an interferon (IFN)-g inducible factor, spontaneously develop Ut-LMS. The use of research findings of the experiment with mouse model has been successful in increasing our knowledge and understanding of how alterations, in relevant oncogenic, tumor suppressive, and signaling pathways directly impact sarcomagenesis. The IFN-g signaling pathway is important for control of tumor growth and invasion and has been implicated in several malignant tumors. In this study, experiments with human tissues revealed a defective expression of PSMB9 in human Ut-LMS that was traced to the IFN-g signal cascade and the significant effect of somatic mutations of Janus kinase (JAK) 1 molecule or PSMB9 gene promoter region on the PSMB9 gene transcriptional activation. Understanding the molecular mechanisms of human Ut-LMS may lead to identification of new diagnostic candidates or therapeutic targets in human Ut-LMS.