LMO2 and T-cell leukemia: For gene therapy, an MLV-based vector was found to have integrated into the LIM domain only 2 (LMO2) gene in human T cells in a gene therapy trial15, 16 and thereby induced T-cell leukemia in the two patients.17, 18, 19, 20 However, the majority opinion was that the selection of LMO2 as an insertion site in the patients was accidental.