S100A12 and cancer: This approach revealed task-specific trends: while demographic variables significantly improved the performance in distinguishing healthy from unhealthy individuals (age and H. pylori status with HPT: mAUROC = 88.0%), protein panels for cancer detection (ARG1, CA2, F13A1, S100A12: mAUROC = 85.3%) and cancer/preneoplasia discrimination (ARG1, CA2, HPT, MAN2A1, LBP: mAUROC = 83.9%) achieved superior performance without demographic variables, indicating that these biomarkers capture disease-specific signals beyond the effects of age and gender.