Human leukemic cells. Abnormal amount of methylated base in DNA

Summary Since information relative to the etiology of human leukemia might derive from study of human leukemic cells [11], base ratio and nearest-neighbor analyses were undertaken with DNA isolated from human leukemic lymphoblasts derived in continuous suspension culture. During these studies, an anomalous base was detected repeatedly in such DNA, which has been identified as 5-methylcytosine. The present report describes methylation studies undertaken with these and other human lymphocytes similarly derived from patients with infectious mononucleosis.