Expression and significances of MiRNA Let-7 and HMGA2 in laryngeal carcinoma.

High mobility group protein A2 (HMGA2) is a reported new oncogene been regulated by tumor suppressor microRNA Let-7. HMGA2 has become a hot topic in fundamental and clinical research of laryngeal carcinoma. The aim of the current study is to investigate the molecular mechanism of Let-7 and HMGA2 in oncogenesis and progression of laryngeal cancer.We used quantitative RT-PCR to detect the expression of miRNA Let-7a and HMGA2 mRNA from 59 pairs of fresh laryngeal cancer tissues and adjacent tissues collected for the laryngeal cancer patient. The expression of HMGA2 protein was detected by western blot method.There is a negative correlation between low expressed miRNA Let-7a and high expression of HMGA2 mRNA in human laryngeal cancer (p < 0.05). The expressions of miRNA Let-7a and HMGA2 have a significant difference in patients with clinical stage I-II and clinical stage III-IV, patients with well-differentiated tumor and patients with poorly differentiated tumor, patients with lymph node metastasis and patients without lymph node metastasis. Spearman correlation analysis of miRNA Let-7a and HMGA2 mRNA showed expression of miRNA Let-7a is negatively correlated with HMGA2 expression.The down-regulation of miRNA Let-7a and up-regulation of HMGA2 promote the invasion and metastasis of laryngeal cancer.