p16 inactivation associated with aggressive clinical course and fatal outcome in TEL/AML1-positive acute lymphoblastic leukemia.

The authors describe a 7-year-old boy with TEL/AML1-positive pre-B acute lymphoblastic leukemia, with hemizygous 9p21 deletion at presentation and no p16(INK4A) protein expression. Despite an initial response to a standard chemotherapy regimen, the patient suffered two hematologic relapses and died 34 months after diagnosis. The authors discuss the possibility that complete p16(INK4A) gene inactivation may adversely modify the prognostic significance of TEL/AML1 fusion in childhood acute lymphoblastic leukemia, and present evidence from clinical and in vitro observations in favor of this assumption.