IRS4 and T-cell acute lymphoblastic leukemia: In humans, point mutations of IRS4 and overexpressions of IRS4 due to chromosomal translocations, were recently identified in human paediatric T-cell acute lymphoblastic leukaemia and subungual exostosis, a benign tumour of bone and cartilage in the distal phalanges of fingers and toes [17], [18], [19].