The expression pattern of UDP-N-acetyl-alpha-d-galactosamine: polypeptide N-acetylgalactosaminyl transferase-3 in early gastric carcinoma.

BACKGROUND AND OBJECTIVES

Tumor development usually is accompanied by alterations of O-glycosylation. Initial glycosylation of mucin-type O-linked proteins is regulated by UDP-N-acetyl-alpha-d-galactosamine: polypeptide N-acetylgalactosaminyl transferase-3 (GalNAc-T3). Although the expression of GalNAc-T3 has been examined in various cancers, the expression has not been characterized in early stages of cancer.

METHODS

Using the specific antibody, we evaluated the expression of GalNAc-T3 in 125 early gastric cancers that were treated as classical gastrectomy with lymphadenectomy, and analyzed the relationship between the expression of GalNAc-T3 and clinicopathological features.

RESULTS

GalNac-T3 was positively expressed in 40 cases (76%) in differentiated carcinomas, whereas in only six cases (8%) in undifferentiated carcinomas (P < 0.001). Positive staining was observed in 17 (26%) intramucosal and in 29 (48%) submucosal carcinomas, indicating that GalNac-T3 tended to be highly expressed as the depth of invasion increased (P < 0.05). Lymph node metastasis tended to be observed more frequently in GalNac-T3 positive than negative cases, and the difference was significant in undifferentiated type cancer (P < 0.05).

CONCLUSIONS

GalNAc-T3 expression was a useful indicator of tumor differentiation in early gastric cancer, and the expression had positive correlation with depth of tumor invasion and lymph node metastasis. This suggests that the overexpression of GalNAc-T3 may have a role in invasion and metastasis in early stages of gastric cancer.