The Conceptual Framework: A Practical Guide.

There is no single definition of the conceptual framework (CF) or consensus on how it is best applied in the research process. However, in this piece, the authors argue that the CF is a tool used to link the literature review, research methodology, and study design. The CF grounds the study in the previous literature, theories, and models. It helps the researcher articulate their rationale for why the study should be performed, justify their study design, and describe the lens through which they analyze a phenomenon or research question. Researchers may find the variable use of terms such as theory, theoretical framework, and CF to be confusing. The authors address the distinction between these terms and present strategies to develop and use the CF throughout the research process. The authors provide practical examples and resources for additional learning.

High CD49f expression is associated with osteosarcoma tumor progression: a study using patient-derived primary cell cultures.

Overall prognosis for osteosarcoma (OS) is poor despite aggressive treatment options. Limited access to primary tumors, technical challenges in processing OS tissues, and the lack of well-characterized primary cell cultures has hindered our ability to fully understand the properties of OS tumor initiation and progression. In this study, we have isolated and characterized cell cultures derived from four central high-grade human OS samples. Furthermore, we used the cell cultures to study the role of CD49f in OS progression. Recent studies have implicated CD49f in stemness and multipotency of both cancer stem cells and mesenchymal stem cells. Therefore, we investigated the role of CD49f in osteosarcomagenesis. First, single cell suspensions of tumor biopsies were subcultured and characterized for cell surface marker expression. Next, we characterized the growth and differentiation properties, sensitivity to chemotherapy drugs, and anchorage-independent growth. Xenograft assays showed that cell populations expressing CD49f(hi) /CD90(lo) cell phenotype produced an aggressive tumor. Multiple lines of evidence demonstrated that inhibiting CD49f decreased the tumor-forming ability. Furthermore, the CD49f(hi) /CD90(lo) cell population is generating more aggressive OS tumor growth and indicating this cell surface marker could be a potential candidate for the isolation of an aggressive cell type in OSs.