The fate of circulating tumor cells. II. A mechanism of cortisone action in increasing metastases.

mon cell emboli. Some blood-borne emboli can no circulate (4—7,9—li). Probably such emboli are not sources of metastases unless they are arrested ultimately in sites favorable for their development (3). This report concerns the effect of cortisone on arrest of tumor cell emboli. Past investigations have shown that cortisone increases metastases (1, 2). Cortisone may promote metastases by in creasing the incidence of arrest of circulating tumor cells. Experiments were developed to test this hypothesis. With microcinematographic tech flies it was possible to count the number of tumor cells passing through or arrested in a capillary bed.