The formation of PML-nucleolar compartments (PNAs) plays a crucial role in cellular senescence by segregating damaged ribosomal DNA (rDNA) from active nucleoli. This segregation helps prevent rDNA instability, which can lead to genomic instability and cellular dysfunction. In the context of cancer, the presence of persistent PNAs can trigger senescence in cancer cells, acting as a protective mechanism against tumorigenesis. On the other hand, in aging cells, the accumulation of PNAs may contribute to the aging process by promoting senescence and limiting the proliferation of damaged cells. Therefore, understanding the role of PNAs in cellular senescence has significant implications for both cancer development and aging-related processes.