Tetrasomy 8 is associated with a major cellular proliferative advantage and a poor prognosis: two cases of myeloid hematologic disorders and review of the literature

We report two cases of acute myeloid leukemia (AML) with tetrasomy X detect ed in patients' bone marrow samples using chromosome GTG-banding, fluoresce nce in situ hybridization (FISH) and primed in situ labeling (PRINS) techni ques. Case 1 was a myelodysplastic syndrome (MDS) in transition to AML-ML4 and case 2 was an AML-M2. in case 1, the tetrasomy 8 was found in 40% of me taphase cells and constituted the only chromosome abnormality. In case 2, i t was accompanied by a double Ph, trisomy 18 and disomy Y and was found in 68% of metaphase cells, However, FISH and PRINS techniques revealed the coe xistence of tetrasomy 8 and trisomy 8 in interphase nuclei of both cases. W hen the proportion of cells with tetrasomy 8 was compared between metaphase s and interphase nuclei, it showed a much higher percentage of cells with t etrasomy 8 in metaphases than in interphase nuclei. Moreover, in case 2, al though multi-PRINS and FISH-PRINS techniques showed other populations of in terphase nuclei with different combinations of chromosome anomalies with re spect to the copy numbers for chromosomes 8, 18, Y and Ph, only cells that contained either a single Ph or tetrasomy g plus trisomy 18, disomy Y, and double Ph could be seen in metaphases. This strongly suggests that tetrasom y 8 confers a higher proliferative advantage to cells. Our cases also show that the tetrasomy 8 is associated with a poor prognosis, (C) 2001 Elsevier Science Inc. All rights reserved.