Methods to Generate and Assay for Distinct Stages of Cancer Metastasis in Adult Drosophila melanogaster.

Metastasis underlies the majority of cancer-related deaths. Until recently, research on this complex multi-step process has been hindered by a lack of genetically tractable experimental models amenable to high-throughput analyses. This was recently overcome with the development of a model of metastatic colorectal cancer (CRC) in adult flies, which relies on the activation of a partial-epithelial-to-mesenchymal transition (EMT) in intestinal tumors. In this model, tumor cells are labeled with both GFP and luciferase reporters, enabling high-throughput analyses. We report here the detailed protocol for generating the model, and assaying for primary tumor burden and distinct stages of metastasis, including the number of circulating tumor cells and secondary metastases.