ObjectiveTo investigate the expression of human microRNA let-7a1 and let-7c in lung cancer tissues and its relationship with clinicopathological features.

MethodsThe surgical specimens and clinical data of 53 cases of lung tissue were collected, including 44 cases of lung cancer used to collect cancer tissue and paracancerous normal tissue, and 9 cases of benign lung disease tissue.The smoking history, TNM stage, pathological differentiation and lymph node metastasis were collected.The total RNA was extracted by Trizol method, and the expression of let-7a1 and let-7c was detected by fluorescence quantitative PCR.The difference of let-7a1 and let-7c expression in lung cancer tissue, paracancerous normal tissue and benign lung disease tissue, and its relationship with clinical features were analyzed.

ResultsThe relative expression of let-7a1 and let-7c in lung cancer tissue was lower than that in paracancerous normal tissue and benign lung disease tissue(P < 0.05), and the relative expression of let-7a1 and let-7c in paracancerous normal tissue was lower than that in benign lung disease tissue(P < 0.05).The expression of let-7a1 was related to differentiating degree, smoking and TNM stage (P < 0.05 to P < 0.01), but was not related to smoking and TNM stage (P>0.05).The expression of let-7c was related to lymph node metastasis and differentiating degree (P < 0.01), but was not related to smoking and TNM stage (P>0.05).

ConclusionsThe relative expression of let-7a1 and let-7c genes in lung cancer tissue decreases, and exhibits decreasing trend with the progress of clinical stage and lymph node metastasis, which suggests that let-7a1 and let-7c are closely related to the occurrence, development and metastasis of lung cancer.Let-7a1 and let-7c may become biomarkers for early diagnosis of lung cancer, and become new targets for targeted therapy of lung cancer, to provide experimental basis for early intervention of high-risk groups.