Clinical significance of mucin-like high molecular weight glycoprotein originated from lung cancer as tumor marker.
A high molecular weight, mucous glycoprotein (MG) from the pleural fluid of lung adenocarcinoma was purified by the DEAE-cellulose, gel-filtration and wheat germ agglutinin affinity chromatography. Protein portion of the molecule was composed of amino acids rich in serine, threonine and proline, but methionine and tyrosine concentrations were relatively low. About 65% of the weight, was composed of galactose, galactosamine, glucosamine, fucose and sialic acid. The gel-filtration pattern on Sepharose 4B revealed Mr greater than 10(6) Da. The SDS-PAGE pattern revealed a main band at the position of the Mr about 350 kDa under the reducing condition. Rabbit antibody against this molecule recognized mainly the peptide portion, and the radioimmunoassay (RIA) using the double antibody method was developed by this antibody. Serum MG level was low in healthy subjects and in benign diseases (0.8 +/- 0.7 U/ml; mean +/- SD and 1.1 +/- 2.3 U/ml, respectively). Thus, 3 U/ml was used as the cut-off value. The mean of serum MG levels and positive rates in malignant diseases were significantly high; 4.4 U/ml and 32.3% in lung cancer, 20.1 U/ml and 77.5% in pancreas cancer 11.6 U/ml and 64.3% in gastric cancer, 12.9 U/ml and 57.1% in hepatoma, 12.3 U/ml and 77.8 in colon cancer. Other malignancies such as ovarial and uterus cancer showed also high levels. Elevated values in these malignancies were observed frequently in patients with metastasis. On the other hand, the false positive cases were found in 10% of benign diseases. Determination of MG seems to be useful for the detection of several kinds of malignancies, but it is not adequately sensitive as a screening method for early cancer detection.
Imokawa
M
M
Central Clinical Laboratory, Shiga University of Medical Science, Japan.
Okabe
H
H
Ochi
Y
Y
Kajita
Y
Y
D000230:Adenocarcinoma / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000302:isolation & purification*; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D006023:Glycoproteins / Q000302:isolation & purification; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D008970:Molecular Weight; D009077:Mucins / Q000302:isolation & purification*; D009363:Neoplasm Proteins / Q000302:isolation & purification*; D010996:Pleural Effusion / Q000378:metabolism; D011863:Radioimmunoassay
D014408:Biomarkers, Tumor; D006023:Glycoproteins; D009077:Mucins; D009363:Neoplasm Proteins