RASSF1 and lung cancer: Notably, the RASSF1C promoter region exhibited a higher TFBS frequency containing CpG sites with low methylation levels, as determined by pyrosequencing.<h4>Conclusions</h4>These findings highlight isoform-specific epigenetic regulation at the RASSF1 locus and suggest that RASSF1A methylation may represent a promising minimally invasive marker in lung cancer.