Tumor-associated glycoprotein-72 (TAG-72) is a high molecular weight tumor-associated glycoprotein, which is known to be overexpressed in various human tumors, but its expression in glioma tissues is unknown. Therefore, the aim of this study was to investigate whether TAG-72 is present in glioma and to evaluate the correlation between TAG-72 expression and the severity of the malignancy of this tumor. Immunohistochemistry and Western blot were used to investigate the expression of TAG-72 protein, respectively, in 152 patients with gliomas. There were 90 men and 62 women (mean age 50.6 +/- 11.8 years). Astrocytoma was found in 130 patients and glioblastoma in 22. No TAG-72 expression was found in the non-cancerous brain tissues. TAG-72 protein expression was identified in 80 patients with glioma (52.6%). The expression level of TAG-72 protein was increased from gliomas with low grades to those with high grades. The highest mean value of TAG-72 protein was found in patients with glioblastoma (P < 0.01), whereas the lowest mean values were found in those with grade I astrocytoma (P < 0.01). Our results provide convincing evidence for the first time that the expression of TAG-72 is up-regulated in human gliomas. The expression levels of TAG-72 in gliomas were associated with the severity of the tumor. Whether positive TAG-72 protein expression can be used as a predictor for prognosis of the patients or as a therapeutic target for glioma requires further investigation.