Serum histamine in non-small cell lung cancer: An observational study in the context of allergo-oncology

ObjectivesThe objective of this study was to assess serum histamine levels in patients with non-small cell lung cancer and investigate their association with tumor metastasis.MethodsA retrospective study was conducted at Lu'an Hospital between 2020 and 2024, including 90 patients (70 with non-small cell lung cancer and 20 with benign pulmonary nodules) selected from an initial cohort of 416 patients after applying strict inclusion and exclusion criteria. Serum histamine levels were measured, and other clinical characteristics and laboratory parameters were obtained directly from the electronic medical record system. Receiver operating characteristic curves were used to evaluate the diagnostic performance. Non-small cell lung cancer patients were stratified by metastatic status for group comparisons and logistic regression analyses.ResultsNon-small cell lung cancer patients had significantly higher serum histamine levels than those with benign nodules (median: 8.58 vs. 5.97 µg/L, p = 0.024). A cutoff of 7 µg/L yielded a sensitivity of 65.7% and a specificity of 65.0% for distinguishing non-small cell lung cancer, with an area under the curve of 0.666. Among non-small cell lung cancer patients, those with metastasis (n = 35) had higher histamine levels than nonmetastatic cases (median: 9.39 vs. 7.18 µg/L, p = 0.001). Complement C3 levels and the neutrophil-to-lymphocyte ratio were also higher in metastatic patients. Multivariable logistic regression analyses showed that serum histamine (odds ratio: 1.213, 95% confidence interval: 1.011-1.455, p = 0.038) and complement C3 (OR: 1.488, 95% CI: 1.104-2.004, p = 0.009) were independently associated with metastasis in non-small cell lung cancer patients.ConclusionsSerum histamine levels were elevated in non-small cell lung cancer patients and were independently associated with tumor metastasis. These findings provide preliminary evidence of a possible connection between histamine and the emerging field of allergo-oncology. Complement C3 was also found to be independently associated with metastasis. Further studies are warranted to validate these results and explore the underlying immunological mechanisms.