Experimental model for predicting metastatic ability of tumors using chick embryo.

At present, there is no established diagnostic method by which the metastatic ability of an individual human cancer can be accurately predicted. We used chicken chorioallantoic membrane (CAM) to predict the metastatic ability of three B16 murine melanoma variant lines and also of human giant-cell carcinoma of the lung. Tumor cells were deposited on the CAM of eggs 10 days after fertilization. On day 7 after the tumor inoculation, the embryos were killed, and the lungs removed, minced and implanted on the CAM of other 10-day-old embryos. On day 7 after this inoculation, the tumors on the CAM were inspected under a surgical microscope, and were also checked histologically. The results accurately reflected the differing metastatic abilities of the B16 melanoma variant lines. Metastases were observed in the lungs of the embryo bearing human giant-cell carcinoma of the lung on the CAM. Using CAM seems to be a suitable way of predicting the malignancy of tumors with metastatic ability.