Background: Osteosarcoma is a rare but aggressive bone cancer that occurs primarily in children. Like other rare cancers, treatment advances for osteosarcoma have stagnated, with little improvement in survival for the past several decades. Developing new treatments has been hampered by extensive genomic heterogeneity and limited access to patient samples to study the biology of this complex disease. Methods: To overcome these barriers, we combined the power of comparative oncology with patient-derived models of cancer and high-throughput chemical screens in a cross-species drug discovery pipeline. Results: Coupling in vitro high-throughput drug screens on low-passage and established cell lines with in vivo validation in patient-derived xenografts we identify the proteasome and CRM1 nuclear export pathways as therapeutic sensitivities in osteosarcoma, with dual inhibition of these pathways inducing synergistic cytotoxicity. Conclusions: These collective efforts provide an experimental framework and set of new tools for osteosarcoma and other rare cancers to identify and study new therapeutic vulnerabilities.

Background: Metastatic colorectal cancer (CRC) continues to be a major health problem, and current treatments are primarily for disease control and palliation of symptoms. In this study, we developed a precision medicine strategy to discover novel therapeutics for patients with CRC. Methods: Six matched low-passage cell lines and patient-derived xenografts (PDX) were established from CRC patients undergoing resection of their cancer. High-throughput drug screens using a 119 FDA-approved oncology drug library were performed on these cell lines, which were then validated in vivo in matched PDXs. RNA-Seq analysis was then performed to identify predictors of response. Results: Our study revealed marked differences in response to standard-of-care agents across patients and pinpointed druggable pathways to treat CRC. Among these pathways co-targeting of fibroblast growth factor receptor (FGFR), SRC, platelet derived growth factor receptor (PDGFR), or vascular endothelial growth factor receptor (VEGFR) signaling was found to be an effective strategy. Molecular analyses revealed potential predictors of response to these druggable pathways. Conclusions: Our data suggests that the use of matched low-passage cell lines and PDXs is a promising strategy to identify new therapies and pathways to treat metastatic CRC.

Syringocystadenocarcinoma papilliferum (SCACP) is an extremely rare cutaneous neoplasm of the apocrine or eccrine sweat glands. Solid and cystic glandular structures with cribriform and tubular architecture along with CK5/6, pankeratin and p63 immuno-profile set apart SCACP from other cutaneous malignancies. Wide local excision (WLE) has been the mainstay treatment for localized SCACP; however, no standard treatment has yet been established for unresectable or metastatic disease. Herein, we report a 74-year-old male with SCACP, who initially presented with a painful nodule on the upper back and later developed metastatic disease. He was treated with carboplatin and paclitaxel with concurrent intensity-modulated radiation therapy (IMRT), which resulted in disease stabilization for 12 months. Next generation sequencing (NGS) revealed a total of 18 genomic alterations associated with potential benefit from targeted therapeutics. PD-L1 expression was identified in 70% of tumor cells. These findings suggest that the opportunity of targeted therapeutics and immunotherapy exist as for metastatic SCACP. Reporting molecular profile of the rare tumors with no established standard treatment options should be encouraged.