HORMONES IN CANCER IX. A RESISTANCE FACTOR IN NORMAL URINE AFFECTING CARCINOMA 256

¹ From the Chemical Laboratory and the Department of Cancer Research, Santa Barbara Cottage Hospital

1. In four series of rats inoculated with carcinoma 256, there were six takes out of 66 inoculations in the controls against twenty-eight takes out of 65 inoculations in animals dosed with the depressor colloid fraction of normal urine.

2. In three series of inoculations in which the percentage of takes in the controls was sufficient (over 45 per cent) to compile tumor growth data, a significant increase in tumor growth of animals dosed with the depressor colloid over tumor growth of controls was noted.

3. A purified depressor fraction failed to produce the effects of the crude fraction.

4. These results indicate that the crude colloid fraction of normal urine contains a substance or substances capable of breaking down the resistance to tumor inoculation and of increasing the rate of tumor growth.