Reduced expression of liver kinase B1 and Beclin1 is associated with the poor survival of patients with non-small cell lung cancer.

Liver kinase B1 (LKB1) regulates cell polarity and has tumor-suppressor functions, while Beclin1 regulates autophagy and is associated with tumorigenesis. The present study quantified the expression level of LKB1 and Beclin1 in non-small cell lung cancer (NSCLC) tissue specimens and examined the possible association with clinicopathological characteristics and the survival of patients. Quantitative real-time reverse transcriptase­polymerase chain reaction (qRT-PCR), western blotting and immunohistochemistry were used to assess expression of LKB1 and Beclin1 in 142 NSCLC tissue samples. The data revealed that expression levels of both LKB1 and Beclin1 mRNA and protein were significantly reduced in the NSCLC tissues compared to levels in the matched surrounding normal lung tissues, and expression of LKB1 protein was associated with Beclin1 expression in the NSCLC tissues. Reduced expression of LKB1 protein was significantly associated with tumor histology (P<0.001) and poor differentiation (P<0.001), but was not associated with tumor lymph node metastasis, TNM stage or patient gender and age, while the reduced expression of Beclin1 protein was associated with tumor histology (P<0.05) and poor differentiation (P<0.05). Univariate analysis revealed that adenocarcinoma, lymph node metastasis, advanced TNM stage and reduced expression of LKB1 and Beclin1 proteins are associated with the survival of NSCLC patients. Multivariate analysis indicated that adenocarcinoma (P<0.05), lymph node metastasis (P<0.05), advanced TNM stage (P<0.001) and reduced expression of LKB1 (P<0.05) and Beclin1 (P<0.001) are all independent prognostic indicators for the survival of NSCLC patients.