Experimental studies on factors influencing the widespread organ distribution of Walker 256 tumour metastases.

The Walker 256 tumour metastases occurring spontaneously or following i.v. experimental inoculation to lungs and lymph nodes were studied. This preferential metastasis or organ selectivity was changed by inducing modifications in the tumour cell itself or in the host. Changes induced in the tumour cell decreased the incidence and organ distribution of metastases if the cell membrane was altered by trypsin; conversely, the trophic effect exerted by glucose on the blood-borne tumour cells, leading to an increase of cell viability and proliferative capacity, resulted in augmented metastasis incidence and widespread organ distribution of metastases. The behaviour of experimentally metastasizing Walker tumour cells could be also influenced by the inhibition of the host immune response (hydrocortisone), irradiation, Luvatren, irradiation + Luvatren), the increased metastatic incidence and extension being proportional to the degree of the immunosuppression produced by these agents. The experimental data support the conclusion that tumour dissemination is the result of complex interactions between the tumour and the host.