PLK1 and non-small cell lung carcinoma: Among 121 NSCLC patients, those with high PLK1 expression had a 5-year survival rate of 24.2%; in contrast, those with moderate expression of PLK1 had a 5-year survival rate of 51.8% (P = 0.001)49, indicating that PLK1 expression is a strong negative prognostic indicator, at least in NSCLC.