Evaluating the Inflammatory Protein Ratio (IPR) as an Inflammation-Based Biomarker for Cancer Diagnosis

Chronic inflammation is increasingly recognized as a key driver of tumorigenesis, affecting both the tumor microenvironment and host response. In this context, circulating inflammatory proteins may provide valuable insights into cancer activity. This study evaluated the diagnostic performance of the inflammatory protein ratio (IPR), a composite index derived from serum protein electrophoresis, in detecting active cancer among hospitalized patients. We retrospectively analyzed clinical and laboratory data from 312 adult patients admitted to the Internal Medicine and Aging Department at Policlinico Foggia, Italy, between November 2023 and July 2024. Patients were stratified according to the presence of active cancer, defined by NICE criteria. The diagnostic accuracy of the IPR was compared with that of conventional inflammatory markers, including C-reactive protein (CRP) and the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), and systemic immune-inflammation index (SII). The IPR showed the highest diagnostic performance, with a sensitivity of 88.1%, a specificity of 75.2%, and an area under the receiver operating characteristic curve (AUC) of 0.868. Its negative predictive value reached 97.6%, underscoring its potential as a rule-out tool for malignancy in hospitalized patients. These findings support the IPR as a promising and cost-effective inflammation-based biomarker for cancer detection, warranting further validation in prospective and molecularly characterized cohorts.