Molecular forms of trefoil factor 1 in normal gastric mucosa and its expression in normal and abnormal gastric tissues.

AIM: To study the molecular forms of trefoil factor 1 (TFF1) in normal gastric mucosa and its expression in normal and abnormal gastric tissues (gastric carcinoma, atypical hyperplasia and intestinalized gastric mucosa) and the role of TFF1 in the carcinogenesis and progression of gastric carcinoma and its molecular biological mechanism underlying gastric mucosa protection.
METHODS: The molecular forms of TFF1 in normal gastric mucosa were observed by Western blot. The expression of TFF1 in normal and abnormal gastric tissues (gastric carcinoma, atypical hyperplasia and intestinalized gastric mucosa) was also assayed by immunohistochemical method. The average positive AO was estimated by Motic Images Advanced 3.0 software.
RESULTS: Three patterns of TFF1 were found in normal gastric mucosa: monomer, dimmer, and TFF1 compound whose molecular weight is about 21 kDa. The concentration of TFF1 compound was the highest among these three patterns. TFF1 was expressed mainly in epithelial cytoplasm of the mucosa in gastric body and antrum, especially around the nuclei. The closer the TFF1 to the lumen, the higher the expression of TFF1. The expression of TFF1 in peripheral tissue of gastric carcinoma (0.51 +/- 0.07) was higher than that in normal gastric mucosa (0.44 +/- 0.06, P < 0.001). The expression of TFF1 in gastric adenocarcinoma was positively related to the differentiation of adenocarcinoma. The lower the differentiation of adenocarcinoma was, the weaker the expression of TFF1. No TFF1 was expressed in poorly-differentiated adenocarcinoma. The expression of TFF1 in moderately-well differentiated adenocarcinoma (0.45 +/- 0.07) was a little lower than that in normal mucosa (P > 0.05). The expression of TFF1 in gastric mucosa with atypical hyperplasia (0.57 +/- 0.03) was significantly higher than that in normal gastric mucosa (P < 0.001). No TFF1 was expressed in intestinalized gastric mucosa. There was no statistically significant difference between the expressions of TFF1 in gastric mucosa around the intestinalized tissue (0.45 +/- 0.07) and normal gastric mucosa (P > 0.05).
CONCLUSION: TFF1 is expressed mainly in epithelial cytoplasm of the mucosa in gastric body and antrum. Its main pattern is TFF1 compound, which may have a greater biological activity than monomer and dimer. The expression of TFF1 in peripheral mucosa of gastric ulcer is higher than that in mucosa 5 cm beyond the ulcer, indicating that TFF1 plays an important part in protection and restitution of gastric mucosa. The expression of TFF1 is increased in peripheral tissues of gastric carcinoma and gastric mucosa with atypical hyperplasia, but is decreased in cancer tissues, implying that TFF1 may be related to suppression and differentiation of carcinoma. The weaker expression of TFF1 in poorly-differentiated carcinoma may be related to the destruction of glands and cells in cancer tissues and the decrease in secretion of TFF1.