The immunohistochemical study revealed that 90% of the CD20+ lymphoid cells were CD25+; Cyclin D1+ cells were positive in a small percentage of the leukemia cells; CD1a, TdT, and CD10 were not expressed by the bone marrow cells; and CD34+ cells were present in 1–2% of the blasts. This evidence concerns the gene CCND1 and leukemia.