The events that drive tumor progression and metastatization initiate within the cancer cell itself, that accumulates mutations and de-differentiate until reaching a very unstable stage. But these events alone are not sufficient to maintain sustained metastasis development and growth. Support from the host is required in order to promote angiogenesis and inhibit immune response that would kill cancer cells. The sum of these events is the result of the interaction between the tumor and cellular or non-cellular components that surround the cancer cells. This concept gained more and more importance during the recent years due to the possibility to develop a wide range of therapeutic strategies to target those components and pathways involved in...