Dormant tumor cells in liver and brain. An autopsy study on metastasizing tumors

In 96 of 100 autopsy cases with metastasizing tumor diseases single disseminated tumor cells were detected in liver or brain tissues. These tumor cells appear to be in a resting state. Most of the resting or dormant tumor cells (dtc) are distinguishable from tumor cells within metastasis (mtc) by morphological criteria such as cell size or density, shape and size of the nucleus. These observations suggest that disseminated cells from many primary tumors might pass through a resting (Go) state before they eventually initiate malignant cell growth and give rise to metastatic colonies. Most likely the dtc are not affected by systemic chemotherapy.