BCR/ABL translocation in adult acute lymphoblastic leukemia: A comparison of conventional and interphase cytogenetic studies

Twenty-four adult Chinese patients with de novo acute lymphoblastic leukemi a (ALL) were studied for the BCR/ABL translocation using both conventional cytogenetics and fluorescence in situ hybridization (FISH). Fight (33%) pat ients had the translocation as shown by FISH and all were B-lineage ALL (8/ 19, 42%). Conventional cytogenetics revealed a t(9;22)(q34;q11) in six of t hem, but was either unsuccessful, or not done in the other two. Seven of th e eight positive cases (88%) showed a breakpoint at the minor breakpoint cl uster region (m-BCR), which was confirmed by reverse transcriptase polymera se chain reaction (RT-PCR). To conclude, the frequency of BCR/ABL transloca tion in Chinese patients with de novo ALL is comparable to patients in the Western hemisphere, in contrast to a previous report. The predominance of m -BCR/ABL fusion among these Chinese patients with BCR/ABL translocation is also similar to patients in the Western population. Fluorescence in situ hy bridization is a sensitive, specific and relatively simple technique for de monstrating this important unfavorable prognostic marker in ALL, even in a routine service laboratory setting. (C) Elsevier Science Inc., 1999. All ri ghts reserved.