Studies on the expressions and clinical significance of miRNAlet 7 and Ras in non-small cell lung cancer

Objective To study the expressions of miRNAlet7 and Ras in non-small cell lung cancer ( NSCLC),and their correlations with clinicopathological features and survival time.Methods In-situ hybridization was used to detect the expression of let7,and SP immunohistochemistry to measure HMGA2 in 68 NSCLC cases ( group A) and 20 cases with normal lungs ( group B).Results The positive rate of let7 in group A was lower than that in group B (39.7％ vs 63.2％ ) ( P ＜0.05).The positive rate of Ras in group A was higher than that in group B (66.2％ vs 25.0％ ) ( P ＜0.01 ).The positive rate of let7 was not related to the age,gender,histological type,cell differentiation,and clinical stages of cancer patients(P ＞0.05).The positive rate of Ras was related to smoking,sex,and histological type of cancer( P ＜0.01 ),and was not related to cell differentiation,lymphatic metastasis,and clinical stages of cancer ( P ＞0.05).There was an obvious negative correlation between let7 and Ras( r =-0.627,P ＜0.01 ).The 2-year survival rate of let7-positive group was higher than that of the let 7-negative group ( x2 =4.84,P ＜0.05).No statistically significant difference was found between Ras-positive and-negative groups ( P ＞0.05 ).Conclusions The lower level of let7 expression,and high level of Ras expression have much to do with the carcinogenesis of NSCLC.The level of let7-positive expression is closely related to prognosis; while Ras may act in cooperativity in the occurrence and development of NSCLC. Key words: MicroRNAs/metabolism; Ras proteins/metabolism; Carcinoma,non-small-cell lung/pathology/metabolism