Clinical trial of the Penn test for cancer.

An independent clinical trial of the Penn seroflocculation test for cancer was carried out in order to learn whether this test might be clinically useful either in differential diagnosis or as a screening test for the detection of cancer. In addition, studies were made of the flocculation titer of sera giving positive Penn tests. Incidental observations were made concerning the reproducibility of the test. The trial provided no evidence that the test might be useful in cancer detection. The test should be improved technologically before further clinical evaluations are undertaken. Further study of the basic mechanisms that bring about the positive Penn reaction appears desirable.