BACKGROUND: Soluble urokinase plasminogen activator receptor (suPAR) is a stable plasma biomarker associated with inflammation and disease. This study tested the association between suPAR levels and incident respiratory, gastrointestinal or other types of cancer in initially cancer-free individuals from a general population-based prospective study.METHODS: Baseline plasma samples, baseline characteristics, and follow-up data were available from 2656 individuals from the population-based Danish MONICA10 study, followed for a median of 12.6 years. Cancer was diagnosed according to ICD-8 and ICD-10 codes and suPAR levels were measured using a commercially available ELISA. The association of suPAR levels with incident cancer during follow-up was analyzed using Cox regression, adjusted for established risk factors and the inflammatory markers C-reactive protein (CRP) and leukocyte numbers.RESULTS: suPAR levels ranged from 0.6-22 ng/ml, and median suPAR level was 4.01 ng/ml. 1 ng/ml increase in baseline suPAR was associated with adjusted hazard ratios (HR) of 1.61 (95% CI: 1.23-2.11, P<0.001), 0.92 (95% CI: 0.69-1.24, P=0.59) and 1.33 (95% CI: 1.13-1.58, P<0.001) of being diagnosed with respiratory, gastrointestinal and other cancer types, respectively.CONCLUSIONS: Elevated suPAR levels were associated with increased risk of incident respiratory cancer and other types of cancer, but not gastrointestinal cancers, independently of established risk factors, CRP and leukocyte numbers. Impact:These findings suggest that inflammation is involved in cancer development. Risk algorithms based on established risk factors and risk-associated biomarkers should be developed and evaluated in large general population-based studies. We suggest suPAR as a candidate for evaluation in cancer risk algorithms.