1. A method to evaluate a candidate protocol or drug for the inhibition of metastasis of a primary tumor which method comprises administering said protocol or drug to a vertebrate subject which has been modified to contain a tumor that expresses green fluorescent protein (GFP) and monitoring the progression of metastasis by observing the presence, absence or intensity of the fluorescence at various locations in said treated subject; monitoring the progression of metastasis in a control subject which has been similarly modified to contain said tumor that expresses green fluorescent protein; and comparing the progression of metastasis in said treated subject with the progress of metastasis in said control subject; whereby a diminution of the progression of metastasis in said treated subject as compared to said control subject identifies the protocol or drug as effective in inhibiting metastasis.