Expression of ER stress and autophagy-related molecules in human non-small cell lung cancer and premalignant lesions

Stress that impairs endoplasmic reticulum (ER) function leads to an accumulation of unfolded or misfolded proteins in the ER (ER stress). Autophagy is a lysosomal pathway involved in the turnover of cellular macromolecules and organelles, which emerging data indicate that ER stress is also a potent inducer of autophagy. ER stress and autophagy are involved in human cancer. We examined the expression of ER stress-related proteins [GRP78 and C/EBP homologous protein (CHOP)] and autophagic proteins (Beclin-1 and LC3) in non-small cell lung carcinomas (NSCLCs), bronchioloalveolar carcinomas (BACs) and atypical adenomatous hyperplasias (AAHs) to understand their role in the NSCLC pathogenesis. The expression of GRP78 and CHOP, Beclin-1 and LC3 were analyzed using immunohistochemistry on tissue sections from 133 NSCLC (69 squamous cell carcinomas, 56 adenocarcinomas (AC) and eight other NSCLCs), 21 BAC and 9 AAH. Expression of GRP78 and Beclin-1 was correlated with low tumor stage (p < 0.001 and p = 0.019, respectively) and longer survival (p = 0.007 and p <0.001, respectively) by KaplanMeier analysis. However, CHOP was correlated with high tumor stage (p = 0.038) and shorter survival (p = 0.012). Expression of GRP78 and Beclin-1 was positively correlated (p = 0.006). Our study showed that the expression of GRP78, CHOP, Beclin-1 and LC3 in lung cancer and its relation with clinicopathologic factors and patients survival. These results suggest that GRP78, CHOP and Beclin-1 may play an important role in tumorigenesis of lung AC and may serve as new prognostic indicators for outcome of the patients with NSCLC.