Molecular diagnosis of leukemic cerebrospinal fluid cells in children with newly diagnosed acute lymphoblastic leukemia.

Cytomorphology and IgH/T-cell receptor g clonal gene rearrangements detected by polymerase chain reaction (PCR) homo/heteroduplex analysis and direct sequencing were evaluated in cerebrospinal fluid (CSF) free of red-blood cells at diagnosis of 37 children with acute lymphoblastic leukemia. Molecular CSF involvement was greater as detected by molecular analysis than observed by morphologic criteria (45.9% vs 5.4%). The 4-year event-free survival was lower in the group with molecularly detected CSF involvement (p = 0.01).