Zebrafish: An Emerging Model for Studying Macrophage Functions in Cancer

Zebrafish provide a convenient and unique model for studying human cancers, owing to the high similarity between zebrafish and human genomes, the availability of genetic manipulation technologies, and the availability of large numbers and transparency of zebrafish embryos. Many researchers have recently used zebrafish cancer models to examine the functions of macrophages in tumorigenesis, tumor growth and metastasis. Here, we present evidence that zebrafish cancer cells produce signals that are conserved with respect to those in humans and lead to the recruitment of heterogeneously activated macrophages in response to specific tumor types and tumorigenic stages, thereby promoting cancer initiation and progression. We also summarize how cancer cells interact with macrophages, emphasizing live imaging studies for visualization of dynamic material interchange.