2591

GALNT3

polypeptide N-acetylgalactosaminyltransferase 3;GALNT3;polypeptide N-acetylgalactosaminyltransferase 3

GalNAc transferase 3|UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 3|UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 3 (GalNAc-T3)|polypeptide GalNAc transferase 3|polypeptide GalNAc-transferase T3|pp-GaNTase 3|

2q24-q31

protein-coding

Extrahepatic bile duct carcinomas (EBDCs) still result in an unfavorable prognostic outcome, and little is known about their biological aggressiveness. Recently, UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyl transferase-3 (GalNAc-T3) was reported to be associated with differentiation and malignant potential of human carcinomas. Here, we investigated 61 EBDCs for their detailed clinicopathological features and GalNAc-T3 expression by immunohistochemistry, and then evaluated the relationships between the clinicopathological features and GalNAc-T3 expression patterns. Most of the EBDCs were massively invasive tumors with frequent vascular or perineural invasion and lymph node metastases. GalNAc-T3 expression was detected in all 61 EBDCs, and the expression patterns could be classified into granular and diffuse types. All four noninvasive or minimally invasive EBDCs were the granular type. Among the 58 minimally or massively invasive EBDCs, the GalNAc-T3 expression pattern at the luminal surface was the granular type in 38 cases (66%) and diffuse type in 20 cases (34%), while the expression pattern at the invasive front was the granular type in 26 cases (45%) and diffuse type in 32 cases (55%). Among the 38 cases with granular-type expression at the luminal surface, 26 cases (68%) remained the granular type and 12 cases (32%) became the diffuse type at the invasive front. All 20 cases with diffuse-type expression at the luminal surface remained the diffuse type at the invasive front. Diffuse-type GalNAc-T3 expression at the invasive front was significantly associated with lymph node metastasis (P<0.05). There were no significant correlations between the GalNAc-T3 expression patterns and other clinicopathological factors, including tumor differentiation, depth of invasion or overall survival. In conclusion, EBDCs alter their GalNAc-T3 expression pattern during tumor growth, and the difference in the GalNAc-T3 expression pattern may be associated with lymph node metastasis. Clinically, preoperative evaluation of GalNAc-T3 expression is considered to be useful for decisions regarding operative procedures.

Initial glycosylation of mucin-type O-linked protein is catalysed by one of the UDP-GalNAc: polypeptide N-acetyl-galactosaminyl transferase-3 (GalNAc-T3). O-glycosylation is important in the binding of cell adhesion molecules, cell differentiation, invasion, and metastasis in tumours. This study was designed to detect GalNAc-T3 expression in lung adenocarcinoma by using immunohistochemical staining, and to evaluate the relationship between the GalNAc-T3 expression level and prognosis and recurrence in completely resected lung adenocarcinoma patients. A low expression of GalNAc-T3 was detected in the cytoplasm of tumour cells in 79 of 148 patients (53.4%) with lung adenocarcinoma. The low expression of GalNAc-T3 was associated with poorly differentiated tumour (P<0.0001), poor pathologic stage (P<0.0001), lymph node metastasis (P<0.0001), and tumour recurrence (P=0.016). The lung carcinoma patients with low GalNAc-T3 expression had a poorer prognosis than those with high GalNAc-T3 expression, using both univariate and multivariate analyses (overall survival: P<0.0001 and P=0.011, respectively). In addition, multivariate analysis of the clinicopathological characteristics of stage I lung adenocarcinoma indicated that the low expression of GalNAc-T3 was a significant independent factor for predicting poor prognosis and early recurrence (P=0.006, rr=2.87 and P=0.019, rr=3.05, respectively). The low expression of GalNAc-T3 may be a useful marker for predicting poor prognosis and early recurrence in completely resected lung carcinoma patients, particularly patients with stage I diseases.