Among the 40 cases of NKTCL tissue, 17 cases showed low expression of both PLK1 and p-PLK1, 17 cases exhibited high expression of both, 5 cases had low PLK1 expression but high p-PLK1 expression, and 1 case had high PLK1 expression but low p-PLK1 expression. Here, PLK1 is linked to extranodal nasal NK/T cell lymphoma.