Intravital imaging of stromal cell dynamics in tumors

Tumor stroma, consisting of the extracellular matrix and multiple cell types such as immune cells, fibroblasts and vascular cells, contributes to the malignancy of solid tumors by a variety of mechanisms. Intravital imaging by different microscopy techniques, especially by confocal and multi-photon microscopy, has proven to be a powerful method for analyzing the cell–cell and cell–matrix interactions in the dynamic tumor microenvironments. Intravital imaging has fostered the acquisition of data on parameters such as motility of different cell types in distinct tumor regions or manipulated with defined challenges, kinetics of tumor cell killing by T cells or macrophage-assisted tumor cell extravasation, functionality of the vasculature, protease activity and metabolic state. Achieving the direct observation of intact tumors offered by intavital imaging provides unique insights into tumor biology that will continue to deepen our understanding of the processes leading to malignancy and of the ways they can be targeted.