Does smoking affect miRNA levels?

Chronic tobacco smoking is associated with chronic systemic inflammation and has been shown in research studies to alter miRNA expression profiles in lung tissue and circulation. Specifically, smoking has been associated with elevated miR-21 in some studies, consistent with smoking-induced chronic airway inflammation. However, the Yenos healthy control population in the validation studies is not exclusively non-smokers — it includes individuals with typical lifestyle patterns. The 1.5× HL threshold was calibrated against this real-world healthy population. A current smoker without cancer is still expected to score in the normal range on OncuraKit. However, heavy smokers should be aware that their baseline may be somewhat higher than never-smokers, and a positive result warrants particularly prompt pulmonary follow-up given the known elevated lung cancer risk from smoking.