The overexpression of the CRLF2 and WT1 genes has been described in acute lymphoblastic and myeloid leukaemia, respectively [23,24], and its assessment can be used, for instance, in addition to minimal residual disease, as a monitoring tool during follow-up in order to evaluate the persistence of disease and risk of relapse [25]. The gene discussed is CRLF2; the disease is myeloid leukemia.