MicroRNA expression profiling of Chinese follicular lymphoma by microarray: A preliminary study.

BACKGROUND: MicroRNAs (miRNAs) have been widely regarded as crucial regulators in various biological processes involved in carcinogenesis. However, the comprehensive miRNA profiles of Chinese follicular lymphoma (FL) remains completely unknown.

METHODS: The Exiqon miRCURY LNA™ microRNA Array (v.18.0) was used to detect the miRNA expression profiles of three Chinese FL samples, and compared to three reactive lymphatic nodes (RLN). Quantitative real-time polymerase chain reaction (qRT-PCR) was used to confirm the selected miRNAs in different series. Three databases (miRAnda, miRBase and TargetScan) were used to predict the putative target genes. Bioinformatic analysis (gene ontology analysis and pathway analysis) was performed for further evaluation.

RESULTS: The microarray assay demonstrated that 1643 miRNAs were expressed; in which 103 miRNAs were upregulated and 68 miRNAs were downregulated, according to P-value (<0.05) and fold change (FC>2-fold). Furthermore, qRT-PCR was used to confirm that miR-17-5p, miR-20a-5p and miR-19a-3p were upregulated, and miR-3615 was downregulated (P<0.05). Bioinformatic analysis (gene ontology analysis and pathway analysis) was used for further evaluation. Pathway analysis indicated that 25 pathways corresponded to differentially expressed miRNAs (P-value cut-off is 0.05). Furthermore, miR-17-5p, miR-20a-5p and miR-19a-3p were validated by qRT-PCR in an independent series including five FL3a and five RLN cases. Data analysis revealed that the changing trend of miR-19a-3p and miR-17-5p expression in the independent series was basically identical with that of the microarray data.

CONCLUSIONS: Our results are the first to reveal the miRNA expression profiling of Chinese FL and three upregulated miRNAs. Furthermore, the expression of miR-19a-3p and miR-17-5p were found to be significantly upregulated in FL3a. Further study needs to be urgently performed to reveal its potential role in the pathogenesis of FL in the near future.