Perchloric acid-soluble serum glycoprotein as an index for tumor cell burden in the early detection of cancer.

Neoplastic cells, particularly human mammary carcinoma cells, shed or secrete glycoproteins which are tumor-specific. These compounds contain N-acetylneuraminic acid (NANA) and they differ from the bulk of serum proteins and glycoproteins in being soluble in perchloric acid. Graded number of R3230 adenocarcinoma (AdCa) cells were implanted subcutaneously in groups of female Fisher rats. At time intervals, while under anesthesia the spleens were dissected out, and blood was drawn from the animals. The blood was examined for NANA levels and the spleen cells for lymphocyte migration inhibition. The serum perchloric acid (PA) soluble proteins and the PA-NANA levels were time-dependent and increased with the number of implanted tumor cells. Maximum levels were found in sera from blood drawn 196 hours or later from animals which received 1,000 tumor cells/rat, or more. At 72 hours or more after tumor cell implantation, migration of splenic lymphocytes from animals which received 100 or more R3230 AdCa cells per animal was inhibited on contact with neuraminidase-treated formalinized R3230 AdCa cells. The magnitude of inhibition increased with time and with the number of implanted tumor cells. Therefore, blood PA-NANA levels and lymphocyte migration inhibition rae parameters for the in-vivo early detection and monitor tumor cell proliferation.