A cancerous tumor (or "solid tumor" in the jargon of oncologists to differentiate them from hematological malignancies) is an organ consisting of two tissues: in the center the cancerous tumor proper and around the ExtraCellular Matrix (ECM), sometimes called stroma, chorion or connective tissue. The concept of connective tissue is interesting because it defines a tissue that travels the entire organism (except the brain) and is a preferred transmitter of mechanical signals. But for the cancer organ - isolated from this connective system - we prefer the term ECM.