Comparative incidence of the rearrangements of TEL/AML1 and ALL1 genes in pediatric precursor B acute lymphoblastic leukemias in India

The TEL/AML1 translocation, which is specific for pre B-cell leukemias is p redictive of a favorable treatment outcome. In contrast, translocations inv olving the ALL1 locus which are associated with both B and non B leukemias predict a poor outcome. To determine the relative distribution of high and low risk molecular subtypes of ALL in India, we analyzed the relative frequ encies of these two translocations. The study included a random selection o f 46 newly diagnosed patients of childhood ALL from the Tata Memorial Hospi tal, Bombay, India. Similar to the frequency observed in other world region s, we found an ALL1 rearrangement in less than 7% (3/46) of pre B-ALL patie nts. In contrast to the 25% frequency reported for other regions the low ri sk molecular subtype characterized by the TEL/AML1 translocation represente d a comparatively smaller fraction (4/46) in this study. These results prov ide a preliminary support for a lower frequency of molecular subgroup of le ukemias with a potential for favorable clinical outcome in precursor B-ALL from India.