Examining circulating or metabolic factors (e.g., MIC-1 or PGE-M) assayable in relatively noninvasive specimens (e.g., blood, urine and stool) may be more facile to collect in clinical settings; however, such factors may lack relative specificity for neoplasia, In contrast, those biomarkers derived from tissue biopsies (e.g., HPGD expression) may offer greater specificity but require invasive procedures (e.g., endoscopic biopsy) for collection. The gene discussed is GDF15; the disease is neoplasm.