Frequency of Citogenetic Abnormalities and the BCR/ABL Fusion Gene In Adult Patients with Acute Lymphoblastic Leukemia (ALL). Multicentric Study From Mexico

(1) To know the frequency of chromosome Ph-positive or BCR/ABL by cytogenetic and RT-PCR studies; (2) to evaluate the clinical prognostic factors and the correlation with cytogenetic abnormalities.

In the present report, we study of 104 adults with ALL de novo from seven different hospitals from Mexico, between November 2008 – June 2010. All patients were de novo and were subjected to karyotyping in bone marrow and RT-PCR from BCR/ABL at diagnosis.

From 104 ALL adults included 47(45%) males and 57(54.8%) females, with age range 17–73 years (mean= 33.81 years). The most frequent subtype FAB were L2 (87%) an L1 (13%) with immunophenotype by LAL-B 95%, and 4.8% bilinear. Blood counts were very low, mean hemoglobin 7.8 g/dL (SD+ 2.61), platelet 67,266 × mm³ (SD 79,627), and leukocytic 37,815 × mm3 (SD 60,905). The grown of liver, spleen and adenomegaly was only 40.4%. 19 (18.26%) karyotypes was not useful. Eigthfive informative karyotypes were subdivided into 6(7%) t(9;22); 49(57.6%) normal; 14(16.5%) hyperdiploid; 2(1.9%) hypodiploid; 2(1.9%) poliploid; and 5(5.8%) rearr(12). Chromosomes 9,11,12 and 3 were the most frequently envolved by structural rearrangements. The frequencies of the BCR/ABL studied with RT-PCR (minor and major break point region); only 4 cases was not useful, then 20/100 was positive; only 2/20 (10%) with the b2a2/b3a2 transcript of the P210^BCR/ABL; the rest 90% with e1a2+ of the P190^BCR/ABL.

The frequency reported for BCR/ABL positive (20%) in Mexican adults with ALL is in concordant with worldwide; but only by RT-PCR. The karyotype has low sensitivity by detection of the t(9;2) but is useful by identify others anormalities in karyotype. We don't have correlation between clinical and cytogenetic characteristics.

No relevant conflicts of interest to declare.