SINCE THE RECIPIENT MOUSE DID NOT CONTAIN THE PYV-MT TRANSGENE, A SENSITIVE PCR TECHNIQUE FOR PYV-MT WAS DEVELOPED TO MONITOR FOR THE PRESENCE OF METASTATIC CELLS IN BODY FLUIDS. THIS SLIDE SHOWS THE DETECTION OF TUMOR CELLS DILUTED IN BUFFER. AS FEW AS 10 CELLS COULD BE DETECTED IN 100 LAMBDA OF BUFFER. THIS TECHNIQUE WAS THEN APPLIED TO THE DETECTION OF METASTATIC CELLS IN THE BLOOD STREAM (NEXT SLIDE).