Paulina Galka-Marciniak, Martyna Olga Urbanek-Trzeciak, Paulina Maria Nawrocka, and Piotr Kozlowski
Nucleic Acids Research, Volume 49, Issue 2, 25 January 2021, Pages 601–620, https://doi.org/10.1093/nar/gkaa1223
miRNAs are short pieces of RNA that modify the expression of most genes. It is a well-known phenomenon that the levels of many miRNAs are differentiated in cancer. In the study, in over 10,000 TCGA cancer samples, over 3,600 cancer somatic mutations were identified and characterized in 29 genes playing a role in miRNA biogenesis. Some of the genes were overmutated in specific cancers and/or had recurrent hotspot mutations. The authors identified a list of miRNAs (including well-known cancer-related miRNAs) whose level was affected by particular types of mutations in either SMAD4, SMAD2, or DICER1 and showed that hotspot mutations in DICER1 not only decrease the level of 5p-miRNAs but also increase the level of 3p-miRNAs. The study presents a comprehensive atlas of mutations in miRNA biogenesis genes that may help in understanding the role of the particular genes in cancer, and may also be a useful resource of information for studying the function of these genes.