Hierarchical clustering of miRNA expression profiles and cGVHD patients. We performed a hierarchical cluster analysis (Pearson’s correlation, complete linkage) based on the 21 most discriminative miRNAs identified (P < .02) (Table 2). The heat map, the corresponding dendrograms, and the belonging patient data are demonstrated in the figure. Green indicates high relative miRNA expression levels, whereas blue indicates low expression. The patients' characteristics are given in the columns above. We identified 2 main patient clusters: the left main cluster includes a major part of patients with cGVHD, whereas the right cluster includes mainly patients without posttransplant cGVHD. Thirty-seven of the 50 cGVHD patients clustered in the group with generally high expression of miRNAs, whereas 17 of the 29 without cGVHD clustered in the group with generally low expression of miRNAs. The frequency of cGVHD patients differed significantly between the 2 main clusters (odds ratio, 4.03; 95% CI, 1.52-10.66, P = .0049). AML, acute myelogenous leukemia; ALL, acute lymphoblastic leukemia; MF, myelofibrosis; MPN, myeloproliferative neoplasia; CLL, chronic lymphocytic leukemia; AA, aplastic anemia; HL, Hodgkin’s lymphoma; BU, busulphan; CY, cyclophosphamide; FLU, fludarabine; TRE, treosulfan; ATG, antithymoglobulin; TBI, total body irradiation; ETO, etoposide.