Background and purpose: δ-catenin is a member of the p120 catenin subfamily

which can directly bind to E-cadherin on the cell membrane

forming E-cadherin/catenin complex. δ-catenin can also affect the cytoskeleton assembly by regulating the activity of Cdc42 (Small GTPase). Therefore

this study detected the expression of δ-catenin and Cdc42 in non-small cell lung cancer (NSCLC) and investigated the relationship between them. Methods: The expressions of δ-catenin and Cdc42 in 122 cases of NSCLC were detected by immunohistochemistry. This study also used Western blot and real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) to detect the protein and mRNA expressions of δ-catenin and Cdc42 in lung cancer tissues. After up-regulating or downregulating δ-catenin in lung cancer cell line

the activity of Cdc42 and invasion ability of lung cancer cells were detected by G-LISA and Transwell. Results: The mRNA and protein expression of δ-catenin and Cdc42 in lung cancer tissues was significantly higher than that in normal lung tissues. In 122 NSCLC cases

the δ-catenin positive expression rate was 65.57% (80/122)

and the Cdc42 overexpression rate was 68.03% (83/122). There was a good correlation between δ-catenin positive expression and Cdc42 overexpression (P0.001). The co-expression of δ-catenin and Cdc42 was related to the high clinical stage

poor differentiation

adenocarcinoma and lymph node metastasis of lung cancer (P0.05)

and was significantly associated with poor prognosis in patients with lung cancer. In the lung cancer cell line

the expression and the activity of Cdc42 were changed by regulating the δ-catenin expression

which affected invasion ability of the lung cancer cells. Conclusion: The δ-catenin expression was significantly correlated with the Cdc42 expression. The co-expression of δ-catenin and Cdc42 in lung cancer was correlated with the poor prognosis of lung cancer.