Size-based Capture of Circulating Tumor Cells for Osteosarcoma
Osteosarcoma (OS) is the third leading cancer in children and teens after lymphomas and brain tumors. The 5-year survival rate for nonmetastatic OS patients is ~ 70% to 80%, but the survival rate for metastatic OS patients is dismal at less than 30% with no new advancements in therapy over the past three decades . Cancer metastasis is a complex process that originates from the cells escaped from the primary tumor into circulatory system. These circulating tumor cells (CTCs) are capable to intravasate, survive in the circulation and migrate into the interstitial space to establish tumor growth at a new location. There has been much research on CTCs from epithelial malignancies, such as breast cancers and prostate cancers. For example, enumeration of CTCs has been used for prognosis of breast cancer in clinics. CTCs were also shown to be a good representation of the primary and/or metastatic tumor that could be used to develop a targeted therapy. Different CTC capture methods have also reported. However, currently there are not much work on capture of CTCs from OS, which has a mesenchymal origin. In this project, considering lack of universal marker for OS CTCs, we tested a size-based capture method to capture CTCs for OS. A filter device based on an 8-µm polycarbonate membrane has been fabricated. A low-number cell counting method has been developed. Different staining protocols have been developed to count the captured OS cells on the membrane. And we obtained over 87% capture efficiency for spiked cell as low as 1.2 cells/ml. We expect the capture of CTCs for OS should lead to better understanding of metastatic OS that could be used for more personalized treatment of OS to break the survival plateau of this deadly disease.