[Influence of E-cadherin promoter methylation and mutation of beta-catenin on invasion and metastasis of nasopharyngeal carcinoma cells].
OBJECTIVE
To study the mechanism of invasion and metastasis in early nasopharyngeal carcinoma (NPC) in relation to E-cadherin promoter methylation and mutation in exon 3 of beta-catenin.


METHODS
Methylation of E-cadherin promoter, mutation in exon 3 of beta-catenin and differential expression of beta-catenin in the primary lesion of 21 NPC and the metastatic lymph node of 21 NPC were investigated by DNA Methylation-Specific PCR, direct sequencing and immunohistochemical method.


RESULTS
Methylation on E-cadherin promoter was showed in 23.8% (5/21) primary lesions and 61.9% (13/21) metastatic lymph nodes (P < 0.01). Mutation in exon 3 of beta-catenin was showed in 3 of 42 tissues: codon 37 (TCT-->GCT), codon 41 (ACC-->GCC) and codon 47 (AGT-->ACT). However, there was no relation between these mutations and invasion or metastasis (P > 0.05). High beta-catenin expression on the membrane without nuclear expression was observed in 42 tissues (P > 0.05).


CONCLUSIONS
1. In NPC, methylation of promoter is a major cause of down-regulation of E-cadherin which may finally lead to detachment and metastasis of neoplastic cells, 2. Mutation in exon 3 of beta-catenin is a rare event in NPC. It may be an early event in the carcinogenesis of NPC but have no significant role in invasion and metastasis and 3. High expression of beta-catenin, as one of NPC characteristics, is not a key factor for invasion or metastasis.
Li
Zhi
Z
Department of Pathology, Sun Yat-sen Medical College, Zhong Shan University, Guangzhou 510089, China.
Lin
Su-xia
SX
Liang
Ying-jie
YJ
D000328:Adult; D000368:Aged; D015820:Cadherins / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009303:Nasopharyngeal Neoplasms / Q000235:genetics* / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D011401:Promoter Regions, Genetic; D051176:beta Catenin / Q000032:analysis / Q000235:genetics*
D015820:Cadherins; D051176:beta Catenin