Simple quantitative method for determining the amount of blood-borne tumor cells: initial in vitro results

In metastasis research it would be useful to determine the number of blood borne tumor cells which are released from a primary tumor into the blood circulation. One way to quantify the number of released tumor cells could be to take blood from a vessel which is located close to a primary tumor and is draining the tumor. The number and viability of tumor cells released into the blood stream at any given time could be measured in cancer patients, especially those known to bear a primary, hematogenous metastasizing tumor. Plating efficiency is a precise method for the quantitative determination of the number of colony-forming cells in an adherent cell population. We performed initial in vitro experiments using plating efficiency to count adherent tumor cells within whole human blood. Exploiting the difference in adherence properties of colon carcinoma cells and blood cells in standard cell culture medium, these initial investigations show that it is possible to determine the plating efficiency of colon carcinoma cells within fresh whole human blood.