APC and non-small cell lung carcinoma: For example, Feng et al. showed that RAR-β methylation levels were abnormally expressed in non-small cell lung cancer (NSCLC) patients, while those with positive APC methylation status in tumor tissues survived longer than those with negative APC methylation, indicating that the methylation of RAR-β or APC is a promising diagnostic or prognostic marker of NSCLC [17].