SP1 and non-small cell lung carcinoma: In this study, we demonstrated that methylation of the CpG island within the VILIP-1 promoter was a significant mechanism mediating VILIP-1 silencing in NSCLC: Methylation-induced suppression of gene transcription may occur by direct interference with the binding of transcription factors such as Sp-1/Sp-3 [20], [26].