Osteosarcoma patient survival has remained stagnant for 30 years. Novel therapeutic approaches are needed to improve outcomes. We examined the expression of Programmed Death Ligand 1 (PD-L1) and defined the tumor immune microenvironment to assess the prognostic utility in osteosarcoma. PD-L1 expression in osteosarcoma was examined in two patient cohorts using immunohistochemistry (IHC) (n = 48, n = 59) and expression was validated using quantitative real time PCR (n = 21) and western blotting (n = 9). IHC was used to determine the presence of tumor infiltrating lymphocytes and antigen-presenting cells (APCs) in the tumor. Expression of PD-L1 was correlated with immune cell infiltration and event-free-survival (EFS). The 25% of primary osteosarcoma tumors that express PD-L1 were more likely to contain cells that express PD-1 than PD-L1 negative tumors (91.7% vs 47.2%, p = 0.002). Expression of PD-L1 was significantly associated with the presence of T cells, dendritic cells, and natural killer cells. Although all immune cell types examined were present in osteosarcoma samples, only infiltration by dendritic cells (28.3% vs. 83.9%, p = 0.001) and macrophages (45.5% vs. 84.4%, p = 0.031) were associated with worse five-year-EFS. PD-L1 expression was significantly associated with poorer five-year-EFS (25.0%. vs. 69.4%, p = 0.014). Further studies in osteosarcoma are needed to determine if targeting the PD-L1:PD-1 axis improves survival.

Overall, behavior therapy and pharmacotherapy produce similar short-term treatment outcomes in primary insomnia.

Highlights Vape shop owners/managers perceive minimal risk and therapeutic benefits of CBD. They held diverse perspectives regarding marijuana retail and its potential impact. Some owners/merchants do not consider the CBD or THC markets in their business. Others indicated high levels of enthusiasm for the growing retail marijuana market.

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. Although histologically defined by the presence of malignant osteoid, the tumor possesses lineage multipotency suggesting it could be derived from a cell anywhere on the differentiation pathway between a mesenchymal stem cell (MSC) and a mature osteoblast. To determine if preosteoblasts (pOB) could be the cell of origin differentiated MSCs were transformed with defined genetic elements. MSCs and pOB differentiated from the same MSCs were serially transformed with the oncogenes hTERT, SV40 large T antigen and H-Ras. Assays were performed to determine their tumorigenic properties, differentiation capacity and histologic appearance. When subcutaneously implanted in immunocompromised mice, cell lines derived from transformed MSC and pOB formed tumors in 4 weeks. In contrast to the transformed MSC, the pOB tumors demonstrated a histological appearance characteristic of osteosarcoma. The cell lines derived from the transformed pOB only had osteogenic and chondrogenic differentiation potential, but not adipogenic ones. However, the transformed MSC cells and standard osteosarcoma cell lines maintained their tri-lineage differentiation capacity. The inability of the transformed pOB cell line to undergo adipogenic differentiation, may suggest that osteosarcoma is derived from a cell intermediate in differentiation between an MSC and a pOB, with partial commitment to the osteoblastic lineage.