Haematologica 2004;89: supplement no. 6 - Supplements ...

90PostersPO-044FISHING NUP98 INVOLVEMENT IN HEMATOLOGICALMALIGNANCIES WITH 11P15 KARYOTYPIC CHANGESLa Starza R,* Crescenzi B,* Rosati R,* Gorello P,*Schoch C, # Romoli S,* Testoni N,° Santoro A, +Martelli MF,* Mecucci C**Ematologia, Policlinico Monteluce, Università degliStudi di Perugia, Perugia, Italy, # Labor fur Leukaemie-diagnostik,Medizinische Klinik III, Munchen,Germany, ° Ematologia, Istituto Seragnoli, Universitadi Bologna, Italy + Ematologia, Università di Palermo,Palermo, ItalyNUP98 gene is one of the so-called promiscuousgenes as at least 15 partners of translocations areknown. It is involved in both de novo and secondaryhematological malignancies such as acute myeloid(AML) and lymphoid leukemias (ALL), Ph-positivechronic myeloid leukemia (CML), T-cell non-Hodgkin’slymphomas. In order to pick up NUP98 rearrangements,we set up a FISH approach with DNA clonesselected for NUP98 and in some cases for the putativepartner genes. We collected twelve cases with aNUP98 translocation and the following diagnosis: 2T-ALL with t(4;11)(q12;p15); one refractory anemiawith excess of blasts and a cryptic ins(5;11) (q35;p15p14); three AML-M2 and one Ph + CML witht(7;11)(p15;p15); one AML with t(8;11) (p11.2,p15);one secondary AML-M2 with t(10;11) (q22;p15); twoAML-M2 with t(11;12) (p15;q13); and one AML-M4with inv(11)(p15q22). NUP98 was investigated byFISH with clone RP5-1173K1 spanning exons 10 to 20of the gene. Additional experiments were performedwith clones selected for the following partner chromosome/genes:5q35/NSD1 (CTC-549A4), 7p15/HOXA (RP1-170K19, 170O19, 18M17, 113H19,167F23), 8p11.2/NSD3 (RP11-350N15), 12q13/HOXC(RP11-877M13, 578A18, 219N9). The RP5-1173K1clone detected NUP98 rearrangements in all casesresulting in three hybridization signals on normal 11,on der(11), and on the partner chromosome. Thisapproach allowed us to identify a crypticNUP98/NSD1 fusion resulting from an insertion ofthe 5NUP98 within the 5q35/NSD1 locus. Clonesselected to study known partner chromosomes/geneswere validated: insertion of 5;NUP98 into NSD1 wasdemonstrated with double colour experiment usingRP5-1173K1 and CTC-549A4; 3/4 patients witht(7;11) showed the same breakpoint at 7p15 withinclone RP1-170O19; the t(8;11) can be easily detect bycombining RP5-1173K1 and RP11-350N15 in doublecolour since two fusion signals are present on bothder(8) and der(11). In one case of t(11;12) the12q13/HOXC breakpoint was narrowed within RP11-877M13.FISH is a useful tool to perform wide screeningof NUP98 involvement. We validated a number ofclones to study specific NUP98 translocations. Thesetools will be helpful to unravel the incidence and theclinical impact of NUP98 rearrangements.Funding: This work was partially supported by CNR-MIUR, and FIRB.PO-045TELOMERASE ACTIVITY IN ACUTE PROMYELOCYTIC LEUKEMIA(AML-M3): A STUDY ON 35 PATIENTSCalatroni S, 1 Bernasconi P, 1 Klersy C, 2 Rocca B, 1Boni M, 1 Cavigliano PM, 1 Giardini I, 1 , Zappatore R, 1Caresana M, 1 Quarna J, 1 Lazzarino M 11Università degli Studi di Pavia, Divisione di Ematologia,Policlinico San Matteo IRCCS; 2 DirezioneScientifica, Unità di Epidemiologia Clinica e Biometria,IRCCS Policlinico San Matteo, Pavia, ItalyTelomerase is formed by two subunits TERC, theRNA template needed for telomere synthesis, andhTERT, the rate-limiting catalytic protein subunit.Telomerase plays a crucial role in preserving thelength of telomeres, nucleoprotein structures positionedat the end of eukaryotic chromosomes. Physiologicalerosion of telomeres occurs after subsequentrounds of cell division and prevents tumour formationby limiting cell life span. However, when some tumorsuppressor genes (namely TP53 or RB-1) are targetedby mutations, the cell enters a period of geneticinstability and may acquire additional geneticdefects. Some of these cells die by apoptosis, whileothers survive due to constitutive activation oftelomerase. Therefore, it is not surprising that hTERTactivity has been found amplified in many haematologicaldisorders. The aims of the present study wereto evaluate whether hTERT activity was correlatedwith peculiar clinical parameters, with the presenceof FLT3 internal tandem duplication (ITD) and withrelapse in 35 LAM-M3 patients. The thirty-fivepatients entered in the present study were analysedat the onset of the disease and during the follow-up.hTERT relative quantification was obtained througha real-time polymerase chain reaction whichemployed SybrGreen I, a DNA-binding fluorescentdye. Serial dilution of total RNA from the K562 cellline were used to set the standard curve for real-timequantification. hTERT expression was normalized toABL and calibrated on K562.In order to make statisticalanalysis hTERT values were dichotomised so thatpatients could be subdivided in those with high andlow hTERT activity. Comparisons of hTERT values duringthe follow-up were made by using a regressionmodel for repeated measurements and correlationswith clinical parameters and relapse were obtained byapplying the Spearman test and Cox regression. Eighteenpatients were males and seventeen females;haematologica vol. 89[suppl. n. 6]:september 2004