Prognostic utility of serum alpha-N-acetylgalactosaminidase and immunosuppression resulted from deglycosylation of serum Gc protein in oral cancer patients.

Abstract

Vitamin D3-binding protein (Gc protein), a serum glycoprotein, is the precursor for the macrophage activating factor. Cancer patient sera contain alpha-N-acetylgalactosaminidase that deglycosylates Gc protein. Deglycosylated Gc protein cannot be converted to macrophage activating factor, leading to immunosuppression. Of 46 oral cancer patients with squamous cell carcinoma, approximately 22% had greatly reduced precursor activities. The precursor activity of approximately 61% of these patients was moderately reduced. The remaining patients (17%) had precursor activities equivalent to those of healthy humans. Patients with low precursor activity of serum Gc protein had high serum alpha-N-acetylgalactosaminidase activity. In contrast, patients with high precursor activity had low serum alpha-N-acetylgalactosaminidase activity. Thus, levels of serum alpha-N-acetylgalactosaminidase of individual patients have an inverse correlation with precursor activities of their serum Gc protein. Surgical removal of tumors resulted in a subtle decrease in serum alpha-N-acetylgalactosaminidase activity with concomitant increase in the precursor activity of serum Gc protein. Serum enzyme analysis of nude mice transplanted with a human oral squamous carcinoma cell line revealed that serum alpha-N-acetylgalactosaminidase activity is directly proportional to tumor burden. Thus, alpha-N-acetylgalactosaminidase activity in patient bloodstream can serve as a diagnostic/prognostic index.

• Authors: N Yamamoto, V R Naraparaju, M Urade
• Journal: Cancer research (Cancer Res) Vol. 57 Issue 2 Pg. 295-9 (Jan 15 1997) ISSN: 0008-5472 [Print] United States
• PMID: 9000571 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antigens, Neoplasm
• Macrophage-Activating Factors
• Neoplasm Proteins
• Serpins
• Vitamin D-Binding Protein
• squamous cell carcinoma-related antigen
• Hexosaminidases
• NAGA protein, human
• alpha-N-Acetylgalactosaminidase

Topics

• Animals
• Antigens, Neoplasm (blood)
• Carcinoma, Squamous Cell (immunology, pathology)
• Female
• Glycosylation
• Hexosaminidases (blood)
• Humans
• Immunosuppression Therapy
• Macrophage-Activating Factors (metabolism)
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Mouth Neoplasms (immunology, metabolism, pathology)
• Neoplasm Proteins (blood, metabolism)
• Prognosis
• Serpins
• Vitamin D-Binding Protein (blood, metabolism)
• alpha-N-Acetylgalactosaminidase