Molecular Diagnosis and Clinical Relevance of t(9;22), t(4;ll) and t(l;19) Chromosome Abnormalities in a Consecutive Group of 141 Adult Patients with Acute Lymphoblastic Leukemia

Over a time period of five years leukemic blast samples from 141 consecutive patients with adult ALL were referred to our laboratory, for molecular evaluation of chromosome abnormalities. The t(9;22), t(4;11) and t(1;19) which are most commonly found in adult ALL with a B-precursor phenotype were molecularly analyzed by similar RT-PCR based protocols. BCR-ABL transcripts generated by the t(9;22) translocation were demonstrated in 36 patients (25%) and were restricted to the 109 patients with B precursor ALL (33% of this group). Of 83 patients showing a common phenotype (CD10+), 34 were BCR-ABL positive (41%) whereas only 2 out of 26 with Null ALL (HLADr+, CD19+, CD10-) were positive. Interestingly, the percent of BCR-ABL positive CD10+ ALL increases significantly with age being 20% in patients less than 30 years old and more than 50% in older patients. None of the T-ALL (24 patients) and B-ALL (8 patients) were positive. The majority of cases (67%) showed the pi90 gene subtype.The cytogenetic diagnosis of...