While using BMI as a ‘lifestyle biomarker’ may appear to be unconventional (compared with traditional gene or protein biomarkers), lifestyle is used as a predictive factor for treatment response of other cancer types; smoking status is used for directing anti-epidermal growth factor receptor (EGFR) therapy (erlotinib) in non-small cell lung cancer. This evidence concerns the gene EGFR and non-small cell lung carcinoma.