PLK1 and extranodal nasal NK/T cell lymphoma: While investigating the role of p53 in natural killer T-cell lymphoma (NKTCL) tumors, some researchers found that p53 was negatively correlated with PLK1 expression in NKTCL tissues as well as in the NK92 cell line and that downregulation of PLK1 initiated the ATM/p53 signaling pathway, which induced DDR and thus facilitated apoptosis in cancerous NK cells (32).