Downregulated anti-angiogenic miR-19a, miR-126 and let-7b in non-small lung cancer have poor but different prognostic values in squamous and adenocarcinoma subtypes

Molecular regulatory mechanisms of lung cancer initiation and progression are poorly understood. Role of micro RNA (miRNA) 19a in lung cancer is still controversial, as well. Treatments of non-small-cell lung cancer (NSCLC), particularly of the squamous subtype are limited. However increasing evidence point many molecular markers as potential prognostic and therapeutic tools. Purpose of this study was to evaluate differences in miR-19a, as well as miR-126 and let-7b expression profiles between NSCLC tumor tissue and healthy lung tissue. Also, the purpose was to evaluate the relationship of miR-19a, miR-126 and let-7b expression to survival outcomes in NSCLC patients but to evaluate the differences of their prognostic values between squamous and adenocarcinoma subtypes. 50 non-small lung cancer patients (32 squamous and 18 adenocarcinoma) and 45 healthy individuals were included. miRNA expression was detected by quantitative real-time polymerase chain reaction. Microvascular density was immunohistochemicaly quantified by factor VIII-related antigen. One- and two-years survival outcomes were observed. Expression of anti-angiogenic miR-19a, miR-126 and let-7b were significantly lower in tumour tissue compared to control lung tissue. Low miRNAs expression correlated with worse progression-free survival in both squamous and adenocarcinoma of the lung. Poor overall survivals were associated with low miRNAs expression only in the squamous lung cancer. Besides miR-126 and let-7b, our observations confirm also anti-angiogenic role of miR-19a in NSCLC patients and suggest the potential new target therapy in squamous lung cancer.