The results of the current meta-analysis revealed that high Ki-67 expression in patients with NSCLC was associated with a poorer prognosis for OS (HR 1.59, 95 % CI 1.35–1.88, P < 0.001), consistent with a previous meta-analysis, published in 2004 [2], but in this case with nearly three–fold as many patients and double the number of studies. Here, MKI67 is linked to non-small cell lung carcinoma.