RNA editing is a crucial post-transcriptional modification that alters the transcriptome and proteome and affects many cellular processes, including splicing, microRNA specificity, stability of RNA molecules, and protein structure. Enzymes from the adenosine deaminase acting on RNA (ADAR) and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC) protein families mediate RNA editing and can alter a variety of non-coding and coding RNAs, including all regions of mRNA molecules, leading to tumor development and progression. This review provides novel insights into the potential use of RNA editing parameters, such as editing levels, expression of ADAR and APOBEC genes, and specifically edited genes, as biomarkers for cancer progression, distinguishing it from previous studies that focused on isolated aspects of RNA editing mechanisms. The methodological section offers clues to accelerate high-throughput analysis of RNA or DNA sequencing data for the identification of RNA editing events.