The yolk sac vasculature in early avian embryo provides a novel model for the analysis of cancer extravasation

Hematogenous metastasis, a key trait of cancer cells, involves a complex sequence of cell migration steps, including intravasation, circulation, arrest in capillary vessels, and extravasation. Among these steps, extravasation is challenging to image in amniotes like humans and mice due to its unpredictable timing and location, limiting our understanding of cellular and molecular mechanisms through imaging. Establishing a new cancer carrier model with high-resolution imaging capabilities in amniotes is crucial. In this study, we investigated the yolk sac vasculature (YSV) of early avian embryos (chickens and quail) as a new model for studying extravasation, offering excellent imaging capabilities. We examined the YSV structure and attempted fluorescent labeling to enhance visibility. We then injected mCherry-labeled HT-1080 cells into YSV and observed their behavior, revealing distinct morphologies and extravasation dynamics. Our findings suggest that the YSV model holds promise as a novel cancer carrier model for elucidating cellular and molecular mechanisms through imaging-based approaches.