This study chose to use the non tumorigenic and untransformed (yet immortalized) bronchial HBEC-3 and HBEC-3 RasV12 cell lines [25] so as to mimic the early-stage loss of RASSF1A expression in lung pre-neoplastic epithelium [26], as well as in cancer-derived RASSF1A-methylated A549 and H1299 cell lines for rescue experiments by re-expressing RASSF1A in such cells. Here, RASSF1 is linked to cancer.