PRAJA, a RING-H2 E3 ligase, is abundantly expressed in brain tissues such as the cerebellum and frontal cortex, amongst others, and more specifically in neural progenitor cells as well as in multiple cancers that include glioblastomas. However, the specific role that Praja plays in neural development and gliomas remains unclear. In this investigation, we performed bioinformatic analyses to examine Praja1 and Praja2 expression across 29 cancer types, and observed raised levels of Praja1 and Praja2 in gliomas with an inverse relationship between Praja1 and apoptotic genes and Praja substrates such as Smad3. We analyzed the role of Praja in the developing brain through loss of function studies, using morpholinos targeting Praja1 in embryonic zebrafish, and observed that Praja1 is expressed prominently in regions enriched with neural precursor cell subtypes. Antisense Praja morpholinos resulted in multiple embryonic defects including delayed neural development likely through increased apoptosis. Further studies revealed high levels of Cdk1 with loss of Praja1 in TGF-β or insulin treated cells, supporting the link between Praja1 and cell cycle regulation. In summary, these studies underscore Praja's role in mammalian brain development and Praja1 deregulation may lead to gliomas possibly through the regulation of cell cycle and/or apoptosis.

Of the 260,000 women diagnosed with breast cancer annually in the United States, more than 60% are treated with breastconserving surgery or lumpectomy, followed by radiation to decrease the chance of local recurrence. More than 70% of breast cancer recurrences are localized to the original tumor cavity. Hence, targeted radiation therapy after lumpectomy is critical for recurrence prevention. With 30,000 patients annually opting for oncoplastic reconstruction of the breast after lumpectomy to improve cosmesis, the resulting tissue rearrangement increases the difficulty for radiation oncologists to accurately delineate the cavity when planning radiation therapy. Owing to the absence of a standardized protocol, it is important to assess the efficacy of various methods used to mark the tumor cavity for improved delineation. Methods and Materials: A keyword search and analysis was used to compile relevant articles on PubMed (National Center for Biotechnology Information). Results: Currently, a common practice for tumor cavity localization is applying titanium surgical clips to the borders of lumpectomy cavity. Tissue movement and seroma formation both impact the positioning of surgical clips within the tumor cavity and lead to significant interobserver variability. Furthermore, the main application of surgical clips is to control the small vessels during surgery, and that can create confusion when the same clips are used for tumor bed localization. All alternative solutions present more precise tumor bed delineation but possess individual concerns with workflow integration, patient comfort, and accuracy. Though liquid-based fiducials were found to be the most effective for delineating tumor cavities, there are still drawbacks for clinical use. Conclusions: These findings should encourage medical innovators to develop novel techniques for tumor cavity marking to increase delineation accuracy and effectively target at-risk tissue. Future solutions in this space should consider the properties of liquid-based fiducial markers to improve radiation oncologists' ability to precisely delineate the tumor cavity.