Background and aims: Collagen type IV and hyaluronic acid (HA) are the major components of basement membrane and extracellular matrix, respectively. Cathepsin D is an aspartyl lysosomal protease involved in the degradation of the basement membrane and extracellular matrix. The aim of this study is to investigate the clinical significance of collagen type IV and hyaluronic acid in gastric juice and serum in diagnosis of gastric cancer and the degrading effect of cathepsin D on collagen type IV and HA.
Methods: Fifty gastric cancer patients were enrolled in our study compared with 41 patients with precancerous lesion and 30 control subjects. Collagen type IV and HA in gastric juice and serum were analyzed by radioimmunoassay. Expression of cathepsin D and collagen type IV in tissue were analyzed by immunohistochemical staining with monoclonal antibodies.
Results: The contents of collagen type IV and HA in gastric juice and HA in serum were significantly higher in patients with gastric cancer than those in patients with precancerous lesion and control group (p < 0.05, p < 0.0001). Gastric cancer patients with lymph node metastasis had a higher level of collagen type IV and HA in gastric juice than those in patients without metastasis (p = 0.049, p = 0.043). The expression of cathepsin D had significantly increased in patients with gastric cancer compared to the control group (p < 0.0001). The continuous expression of collagen type IV in basement membrane in gastric cancer group was lower than that in the precancerous lesion group and control group (p < 0.0001).
Conclusions: The analysis of collagen type IV and HA in gastric juice and serum may provide a simple aid in diagnosing gastric cancer and evaluating whether metastasis is occurring or not.