What is post-transcriptional gene regulation and why does it matter for cancer?

Post-transcriptional regulation refers to the control of gene expression after DNA has been transcribed into RNA but before the RNA has been translated into protein. MicroRNAs regulate at this step — they bind to messenger RNA (mRNA) and either block its translation or trigger its degradation, effectively reducing protein output from specific genes. In cancer, dysregulation at the post-transcriptional level is pervasive. Cancer cells hijack miRNA pathways to suppress tumor suppressors and amplify growth signals. Because miRNA changes can precede the protein changes that traditional biomarker tests detect, miRNA-based screening can identify cancer signals earlier in the disease course.