Two studies [9, 20] investigated the correlation between WIF-1 expression or methylation status and 5-year overall survival, indicating that NSCLC patients with low WIF-1 expression or WIF-1 positive methylation were found to have a significantly lower rate of 5-year overall survival compared to the patients with high WIF-1 expression or WIF-1 negative methylation in their tumor tissues (Figure 5). This evidence concerns the gene WIF1 and neoplasm.