AHRR and lung cancer: Of the five CpG sites included in our methylation risk score, cg05575921 (AHRR) is the most well-established biomarker of smoking exposure.32–34 A study by Jacobsen et al suggested that integrating cg05575921 (AHRR) methylation with NLST screening criteria can improve the specificity of lung cancer screening by excluding those individuals with the lowest lung cancer risk from the eligible population.35