| It is reported that up to 33% of all the coding genes are negatively controlled by microRNAs (miRNAs). Therefore, miRNAs can influence the phenotypes of cancer cells through regulating their target mRNAs. Laryngeal carcinoma is the most common malignant disease of the head and neck, and its incidence is only less than lung cancer among the malignancies risen from the respiratory tract. There are few accomplished study reports on the characteristic miRNA expression profiles and differentially expressed miRNAs associated with various phenotypes of laryngeal carcinoma heretofore.In this study, analysis of DNA microarrays-based miRNA expression profiles of squammous cell carcinoma (SCC) of larynx was performed, to screen out the characteristic miRNA expression profiles and to identify the differentially expressed miRNAs associated with various clinical behaviors. Here both archived formalin-fixed and paraffin-embedded (FFPE) tissue blocks and fresh frozen tissue samples were used for the investigation.The total RNAs were prepared from the FFPE blocks derived from 24 primary tumors of laryngeal SCC and fresh frozen tissue samples of another 8 laryngeal SCC, respectively, and then hybridized with the Agilent Human miRNA microarrays which contains 723 probes for human miRNAs. The microarray data was processed with softwares, including GeneSpring GX, R-Project, etc. Based on bioinformatical analysis, the miRNA expression profiles of laryngeal SCC were obtained. A total of 319 miRNAs were identified and among them 96 were detected in all the 24 FFPE tissue samples; whilst 342 miRNAs were identified and among them 161 were detected in all the 8 fresh frozen tissue samples. Comparing data of the two groups, 233 out of 319 miRNAs detected in FFPE blocks can also be selected in 8 fresh frozen tissue samples; among them 16 miRNAs associated with lymphatic metastasis (p<0.05) were identified both in FFPE and fresh frozen tissue samples. This confirmed the validity of the miRNA expression profile of the FFPE tissue samples. After narrowing the false discovery rate (FDR<0.05),5 differentially expressed miRNAs were found to be significantly associated with the lymphatic metastasis of laryngeal SCC, including miR-23a*, miR-28-5p, miR-15a, miR-16 and miR-425.In conclusion, a panel of differentially expressed miRNAs (miR-23a*, miR-28-5p, miR-15a, miR-16 and miR-425) derived from the miRNA expression profile may serve as the potential molecular biomarkers for the prediction of metastasis or development in laryngeal squamous cell carcinoma. Histopathological archives of well-annotated formalin-fixed paraffin-embedded tissue specimens are the valuable resources for miRNA study including collecting RNA samples for miRNA microarray analysis. |
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