Immunofluorescence analysis conducted on A549 and H460 cells, treated for 24 h with 1 μM SNS032, showed a notable increase in the nuclear p53 levels, confirming that CDK9 inhibition enhances the expression of p53 tumor suppressor in K-Ras mutant NSCLC cells (Figure 2D,E). Here, KRAS is linked to non-small cell lung carcinoma.