The occurrence of the 15;17 translocation in acute promyelocytic leukemia

Combined cytogenetic, FISH and molecular analysis in acute promyelocytic leukaemia at diagnosis and in complete remission

This study reports the results of a simultaneous application of cytogenetic fluorescence in situ hybridization (FISH) and molecular analysis (RT-PCR) in 28 APL cases (23 M3 and five M3v; 26 studied at diagnosis and two at relapse). FISH on metaphases identified the t(15;17) in all cases who were positive for the PML/RAR alpha transcript by RT-PCR. Conventional cytogenetics revealed the t(15;17) in only 68% of cases. However, it enabled the detection of additional chromosome changes in five cases, three of whom were M3v. 11 patients were also investigated during complete remission (CR) by both FISH and RT-PCR, in order to evaluate residual disease; the duration of CR at the time of analysis ranged between 1 and 16 months, with three patients being studied twice. Comparison of RT-PCR and FISH results showed a very good correlation. In fact, of the 10 samples which were RT-PCR positive for residual disease, all were also recognized by interphase FISH, and eight were positive by metaphase FISH. Of the three samples negative at RT-PCR, all were also negative at the interphase FISH. The results of this study indicate that: (a) the t(15;17) is present in all cases positive for the PML/RAR alpha rearrangement, thus in virtually all true APLs; (b) standard cytogenetics, capable of unravelling the t(15;17) in only 68% of cases, enables recognition of additional chromosome changes of potential clinical and prognostic significance; (c) FISH on interphase nuclei is a reliable tool for the monitoring of residual disease, with a sensitivity greater than that of FISH on metaphase cells and superimposable to that of RT-PCR.

Geographic heterogeneity of neoplasia-associated chromosome aberrations

Using a database comprising 13,266 cytogenetically abnormal neoplasms, the geographic heterogeneity of neoplasia-associated chromosomal abnormalities was investigated by comparing the frequencies of characteristic aberrations in consecutive series of patients with the same diagnosis. Significant frequency differences between geographic areas were found for the aberrations +8, i(17q), +19, and an additional Ph1 chromosome in chronic myeloid leukemia (CML); -5, 5q-, and +8 in acute nonlymphocytic leukemia (ANLL); t(8;21) in ANLL-M2; t(15;17) in ANLL-M3; 5q- and -7 in myelodysplastic syndromes (MDS); t(9;22) and +21 in acute lymphocytic leukemia (ALL); t(14;18) in follicular lymphoma; -8 and -22/22q- in meningioma; and structural abnormalities of 12q in pleomorphic adenoma of the salivary glands (PAS). No geographic incidence variation was detected for -7 and +21 in ANLL; +8 in MDS; 6q- and +8 in ALL; +12 in chronic lymphocytic leukemia; 6q- in non-Hodgkin's lymphoma (NHL); t(8;14) in Burkitt's lymphoma; t(11;22) in Ewing's sarcoma; i(12p) in germ cell tumors; 1p- in neuroblastoma; structural abnormalities of 3q, 8q, and 9p in PAS; or 3p- in renal cell carcinoma. Intraregional frequency similarities between cytogenetically identical abnormalities in related tumor types were also analyzed. No significant correlations were found regarding the incidence of 5q- in ANLL and MDS, 6q- in ALL and NHL, -7 in ANLL and MDS, +8 in ANLL and CML, +8 in ANLL and MDS, +8 in ALL and ANLL, or +21 in ALL and ANLL. The findings indicate that some geographic heterogeneity of tumor-associated aberrations exists both in hematologic neoplasms and in solid tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Translocation (15;17) in acute promyelocytic leukemia in Germany

We report on the cytogenetic findings in six cases of acute promyelocytic leukemia, studied in two different cytogenetic laboratories in Germany. A t(15;17) was detected in three cases. This finding reveals that the t(15;17) in acute nonlymphocytic leukemia type FAB M3 also exists in Germany as a nonrandom anomaly and indicates that it occurs with high frequency in this country.