Germline or somatic mutations in genes encoding microRNAs as biomarkers predicting the risk of adult T-cell leukemia/lymphoma.

Single nucleotide polymorphisms in microRNA genes (miRNA-SNPs) can alter miRNA maturation or target mRNA recognition, resulting in gain- or loss-of-function, and are associated with various diseases. This study aimed to identify miRNA-SNPs or somatic mutations in miRNA gens that could serve as biomarkers for the onset or progression of adult T-cell lymphoma-leukemia (ATLL), using next-generation sequencing (NGS) targeting 1809 pre-miRNA genes. Genomic DNA extracted from peripheral blood samples from 31 ATLL patients with low human T-cell leukemia virus type-1 (HTLV-1) proviral loads and 28 healthy subjects was analyzed. Fourteen miRNA-SNPs with significantly different allele frequencies were between the two groups were identified. To determine whether the observed variants were germline or somatic, miRNA-SNPs detected in blood-derived DNA were compared with those from saliva-derived DNA in 6 out of 31 patients. Concordant results between the two sources suggested the variants were germline SNPs. Furthermore, comparison of blood-derived DNA samples from 10 ATLL patients collected during low and high HTLV-1 proviral load periods revealed 10 somatic mutations in pre-miRNA genes, including pre-mir-142, present only in high proviral load samples. These somatic mutations may serve as markers of ATLL progression. In conclusion, out comprehensive NGS analysis identified both germline miRNA-SNPs and somatic mutations that may act as biomarkers for the onset or progression of ATLL. Future studies with larger cohorts will be essential to validate their clinical utility.