A Preliminary Evaluationof Tissue PolypeptideAntigen in Serum or Urine (or Both) of Patients with Cancer or Benign Neoplasms

serum and urine, as an index to the presence of cancer. In the assay, serum, which is first absorbed with human albumin-labeled sheep erythrocytes, or untreated urine (diluted with an equal volume of TPA-free serum) is incu-bated with antibody specific to Tissue Polypeptide Antigen and then reacted with sheep erythrocytes labeled with Tissue Polypeptide Antigen. We found an increased con-centration of Tissue Polypeptide Antigen in the serum of 378 of 513 (74%)and in the urine of 49 of 77(64%) pa-tients with cancer, as compared with 40/112 (36%) and 7/29 (24%), respectively, for individuals with benign neoplasms. Normal individuals were defined as those with less than 0.09 unit of the antigen per milliliter of specimen. Concentrations exceeding this were found in 2/67 (3%) sera and 6/56 (11 %) urines from supposedly norma