We assessed ten-eleven translocations (TET) 1, 2, and 3, isocitrate dehydrogenase (IDH) 1, and 2 messenger RNA (mRNA) expression using real-time PCR on purified leukemic B cells from 214 CLL patients (median follow-up = 75 months, range 1–380), normal peripheral blood B cells (n = 20), and umbilical cord blood B cells (n = 21). The gene discussed is IDH3A; the disease is B-cell chronic lymphocytic leukemia.