Finally, earlier studies during childhood investigated YKL-40 in plasma as a prognostic factor for acute lymphoblastic leukemia [46], in the serum of children with hepatitis C and β-thalassemia as a marker of liver fibrosis, hepatic siderosis, and heart disease [47], and in the serum and bronchoalveolar lavage of children with community-acquired pneumonia [48]. Here, CHI3L1 is linked to acute lymphoblastic leukemia.