Predictive Value of a CpG Methylation Classifier for Relapse in Adults with T-Cell Lymphoblastic Lymphoma: A Multicentre Study

Background: Adults with T-cell lymphoblastic lymphoma (T-LBL) generally benefit from treatment with acute lymphoblastic leukemia (ALL)-like regimens, but approximately 40% will relapse after such treatment. We evaluated the value of CpG methylation in predicting relapse for adults with T-LBL treated with ALL-like regimens. Methods: A total of 549 adults with T-LBL from 27 medical centers were included in the analysis. Using the Illumina Methylation 850K Beadchip, 44 relapse-related CpGs were identified from 49 T-LBL samples by two algorithms, Least Absolute Shrinkage and Selector Operation (LASSO) and Support Vector Machine-Recursive Feature Elimination (SVM-RFE). We built a four-CpG classifier using LASSO Cox regression based on association between the methylation level of CpGs and relapse-free survival (RFS) in the training cohort (n=160).The four-CpG classifier was validated in the internal testing cohort (n=68) and independent validation cohort (n=321). Findings: The four-CpG-based classifier discriminated T-LBL patients at high risk of relapse in the training cohort from those at low risk (p