Proliferative and metastatic potential of exfoliated colorectal cancer cells.

Exfoliated colorectal carcinoma cells were obtained by lavage of 27 freshly resected tumor-bearing segments of human bowel with the use of either Hartmann's solution or medium 199. The tumor cells were isolated from the lavage fluid on Nycodenz (Nyegaard, Oslo, Norway) columns. Their proliferative and metastatic potentials were investigated by their ability to incorporate tritiated thymidine ([3H]dThd) and by their ability to form experimental pulmonary tumors following iv injection into immune-deprived stain A mice. Tumor cells from 7 of 12 patients incorporated [3H]dThd as detected by autoradiography of the cells. Pulmonary nodules of colorectal carcinoma were seen in a single mouse after iv injection of tumor cells from 6 of 17 patients and were histologically distinct from spontaneous lung cancers seen in 3 other animals. No tumors were seen in 12 immune-deprived mice receiving tissue culture medium 199 only. Thus exfoliated colorectal carcinoma cells can undergo further division and might give rise to implantation metastases in humans.