Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 0 0 2026 01 15 1 7 Mozhgan Moghtaderi Allergy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Abbas Rezaianzadeh Cancer Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Seyed Hesamedin Nabavizadeh Allergy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Zahra Kanannejad Allergy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Zahra Khosravizadegan Cancer Research Center, Shiraz University of Medical Sciences, Shiraz, Iran Kimia Asnaashari Allergy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran 2025 07 10 2025 09 12 Allergy and lung cancer are two distinct health concerns. While allergies are typically associated with heightened immune activity, such immune responses may also influence the tumor microenvironment. This study aimed to investigate a potential link between allergic conditions and the risk of lung cancer. We conducted a case-control study analyzing 82 histologically confirmed lung cancer patients and 82 healthy controls from 2019 to 2022. Data were collected through structured questionnaires assessing asthma, allergic rhinitis (AR), food/drug allergies, and chronic urticaria. Statistical analyses included independent samples t-tests and chi-square tests, with significance set at a predetermined threshold. We observed a significant inverse association between AR and lung cancer (8.54% vs 47.56% in controls; OR=0.14, 95% CI: 0.06–0.32). No significant associations were found for asthma (7.32% vs 3.66%), chronic urticaria (3.66% vs 3.66%), drug allergy (4.88% vs 1.22%), or food allergy (2.44% vs 6.10%). The association between AR and lung cancer remained robust after adjustment for demographic factors. AR demonstrated a strong negative association with lung cancer, suggesting potential protective mechanisms distinct from other allergic conditions. These findings support the growing evidence for allergy-cancer immunomodulatory interactions and highlight the need for mechanistic studies on AR-specific pathways in oncogenesis. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4513 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4513/2282