A means for following the growth of experimental neoplasms involves administering
recombinant tumor cells containing an expression construct encoding a secretable
marker to an experimental animal and measuring secreted marker in the urine of
animals bearing tumors formed by such recombinant tumor cells. Urinary marker levels
are quantitatively related to tumor loads. Urinary marker can be detected before
tumors are grossly visible or clinically apparent. Marker levels decrease following
surgical excision or chemotherapeutic treatment, with an estimated half-life of
11 hours. This approach is applicable to the study of many experimental tumor systems.
