The concentration of placental proteins(pp)in the serum of normal subjects, pregnant women, malignant tumor patients and elderly patients was examined by specific enzyme-linked-immunosorbent assay(pp-ELISA), The results were as follows: 1, the levels of pp in normal subjects and pregnant women were relatively low with the optical density of 0.05±0.025 and 0.07±0.035 respectively; 2, pp-positive result(OD>0.13)was found in serum from 3 out of 6 cases of rectal carcinoma, 1 out of 4 cases of ovarian carcinoma, 4 out of 11 cases of breast carcinoma, 7 out of 29 Cases of pulmonary carcinoma, 4 out of 13 cases of gastric carcinoma, 10 out of 19 cases of carcinoma, 3 out of 8 cases of nasopharyngeal carcinoma, 3 out of 8 cases of esophageal carcinoma, 2 out of 2 cases of medias tinal tumor and 6 out of 20 cases of miscellaneous cancer; 3, pp-positive result was found in the serum from 8 out of 30 cases of elderly patients. In these 8 cases, 2 cases had died, 1 case was diagnosed as rectal carcinoma, 2 cases were tumors under suspicion. The results suggested that pp-level might be of help in diagnosis and prognosis.
