[Expressions of Axin and beta-catenin in non-small cell lung cancer].
OBJECTIVE
To investigate the protein expression of Axin and beta-catenin, the exon 3 mutation status of beta-catenin and their clinicopathological correlations in non-small cell lung cancer (NSCLC).


METHODS
A total of 100 NSCLC samples and their corresponding normal lung tissues were obtained from the patients undergoing surgery in the First Affiliated Hospital of China Medical University between 2001 and 2003. Protein expressions of Axin and beta-catenin were detected by immunohistochemistry. DNA sequence alterations of exon 3 of beta-catenin were investigated by polymerase chain reaction (PCR) and direct sequencing.


RESULTS
A reduced membranous expression rate of beta-catenin was observed in 80.0% of the cases (80/100) along with a nuclear expression rate of 26.0% (26/100). There was a significant difference in beta-catenin expression between well and poorly differentiated NSCLCs. Well to moderately differentiated NSCLCs showed a reduced expression rate of 70.0% (35/50), in contrast to 90.0% (45/ 50) in poorly differentiated tumors (P = 0.012). Reduced beta-catenin expression rate was 87.3% (48/55) in cases with lymph node metastasis, in contrast to 71.1% (32/45) in cases without lymph node metastasis (P = 0.044). The positive expression rate of Axin was 48.0% (48/100). Well to moderately differentiated NSCLCs demonstrated a 60.0% positive expression rate of Axin (30/50), much higher than poorly differentiated tumors [36.0% (18/50), P = 0.016]. The positive expression rate of Axin in beta-catenin nuclear expressed NSCLCs was 15.4% (4/26), much lower than cases without beta-catenin nuclear expression [59.5% (44/74), P < 0.001]. Axin nuclear expression was found in two cases in this study, suggesting that it may function as a nuclear-cytoplasmic shuttling protein. PCR and direct sequencing failed to reveal any exon 3 mutation of beta-catenin gene.


CONCLUSIONS
The reduced membranous expression of beta-catenin is associated with poorly differentiated and lymph node positive NSCLCs. The expression of Axin is inversely correlated with the degree of tumor differentiation and nuclear expression of beta-catenin. The exon 3 mutations do not contribute to the abnormal protein expression of beta-catenin in NSCLCs.
Xu
Hong-Tao
HT
Department of Pathology, College of Basic Medical Science, China Medical University, Shenyang 110001, China.
Wang
Liang
L
Lin
Dong
D
Liu
Yang
Y
Liu
Nan
N
Wang
En-Hua
EH
D000328:Adult; D000368:Aged; D060466:Axin Protein; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D005091:Exons; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D012097:Repressor Proteins / Q000378:metabolism*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
D060466:Axin Protein; D012097:Repressor Proteins; D051176:beta Catenin