Plasma YKL-40 was independent of other routinely used biomarkers (i.e., estrogen receptor status, KRAS mutation status, serum levels of human epidermal growth factor receptor 2 (HER2), CEA, carbohydrate antigen (CA) 125, prostate-specific antigen (PSA) and lactate dehydrogenase (LDH) and clinical parameters (i.e., age, performance status, tumor stage, histology) when tested in multivariate Cox analysis [32,36,48,49,50,51,52,53,54,55,56,58,59,60,61,62,63,64,66]. The gene discussed is CHI3L1; the disease is neoplasm.