Malignant tumors pose a major threat to survival largely because they shed mobile cells that can form secondary tumors in other tissues. This process requires a fundamental change in the character of cells within the primary tumor, insofar as members of a localized cell mass must be converted into actively migrating cells that invade into the surrounding tissue and blood vessels, and finally settle in distant tissues. A growing body of evidence suggests that inflammatory reactions promote such cellular transformation.
Image: Colon carcinoma (brown staining). Note how individual tumor cells (brown) or groups of tumor cells have become detached from the primary tumor (on the left) and are migrating into the surrounding normal tissue (the so-called stroma, blue staining).
Inflammation mobilizes tumor cells
Image credits: Rene Jackstadt