The discovery of hillocks and their association with squamous metaplasia has significant implications for understanding and potentially treating lung cancer. Squamous metaplasia, traditionally considered a precursor of lung cancer, is now linked to the expansion of hillock basal stem cells in response to vitamin A deficiency. This finding suggests that hillocks may serve as one origin of squamous metaplasia, shedding light on the mechanisms underlying the progression from metaplasia to lung cancer. By understanding the role of hillocks in squamous metaplasia, researchers may uncover new targets for intervention and treatment strategies aimed at preventing the development of lung cancer. Additionally, the identification of human hillocks capable of generating functional squamous barrier structures in culture opens up possibilities for studying lung cancer pathogenesis and developing novel therapeutic approaches targeting these unique stem cell populations.