In this study, we compared AT clonal cells, representing 88% of the entire T lymphocytes (AT94-1) and expressing TCL1 oncogene (ATM(-) TCL1(+)), cell cycle progression to T lymphocytes of AT patients without TCL1 expression (ATM(-) TCL1(-)) by analysing their spontaneous apoptosis rate, spontaneous telomerase activity and telomere instability.     ///    "We show that in ATM(-) TCL1(+) lymphocytes, apoptosis rate and cell cycle progression are restored back to a rate comparable with that observed in normal lymphocytes while telomere dysfunction is maintained.. "