Dysregulation of gene expression mechanisms has been observed in many tumors, making their analysis of utmost importance. These mechanisms include DNA methylation, an epigenetic mechanism in which 5-carbon of cytosine becomes methylated, leading to gene silencing, and action of short RNA molecules called microRNAs, which regulate protein synthesis at post-transcriptional level by binding to mRNAs. In this review, we describe major roles of both mechanisms in carcinogenesis, offer an overview of currently used methods for their analysis, and summarize most recent advances in electrochemical-based assays and strategies. Advantages of electrochemistry, including favorable cost, time of experiment, or simple instrumentation, are highlighted, along with current challenges that need to be addressed prior to successful application into clinical routine.