ALBERT

Description: We describe a new AML entity, occurring in 30% of de novo acute myeloid leukemia, due to structural and epigenetic deregulation of the UNCX homeobox (HB) gene. By molecular approaches, we identified a M5 AML patient with a t(7;10)(p22;p14) translocation as the sole cytogenetic anomaly and showing ectopic expression of UNCX (7p22.3), which encode for a transcription factor involved in somitogenesis and neurogenesis. Since UNCX was never reported in association with cancer but only with common myeloid cell proliferation and regulation of cell differentiation, we decided to investigate its contribution to leukemogenesis. We observed UNCX ectopic expression in 32.3% (20/62) and in 8% (6/75) of acute myeloid leukemia (AML) patients and cell lines, respectively. Notably, retroviral-mediated UNCX transfer in CD34+ HSCs induced a slow-down in their proliferation and differentiation and transduced cells showed a lower growth rate but a higher percentage of CD34+ stem cells in liquid culture than controls. Additionally, UNCX infected cells displayed a decrease of MAP2K1 proliferation marker but increase of KLF4, HOXA10, and CCNA1, associated with impaired differentiation and pluripotency. Similarly, UNCX-positive patients revealed alteration of gene pathways involved in proliferation, cell cycle control and hematopoiesis. Since HB genes encode for transcription factors showing a crucial role in normal hematopoiesis and in leukemogenesis, we focused our attention on the role of altered UNCX expression level. Of note, its murine ortholog, (Uncx) was previously described as embedded within a low-methylated regions (≤ 10%) called "canyon" and dysregulated in murine hematopoietic stem cells (HSCs) as a consequence of altered methylation at canyons edges (borders) due to Dnmt3a inactivation. In our hands, UNCX activation was accompanied by methylation changes at both its canyon borders, clearly indicating an epigenetic regulation of this gene, although not induced by DNMT3A mutations. Clinical parameters and correlation with response to therapy will be presented. Taken together, our results indicate that more than 30% of de novo AML have a novel entity with a putative leukemogenic role of UNCX, whose activation may be ascribed to epigenetic regulators. Acknowledgments: MG, CP, GS, and AP(2) and this work was supported by ELN, AIL, AIRC, progetto Regione-Università 2010-12 (L. Bolondi), Fondazione del Monte di Bologna e Ravenna, FP7 NGS-PTL project. CTS, GD and AL are supported by Associazione Italiana Ricerca sul Cancro (AIRC) funding. Disclosures Nadarajah: MLL Munich Leukemia Laboratory: Employment. Martinelli:MSD: Consultancy; Novartis: Consultancy, Speakers Bureau; Ariad: Consultancy; BMS: Consultancy, Speakers Bureau; Pfizer: Consultancy; AMGEN: Consultancy; ROCHE: Consultancy.

Description: Our aim was to investigate whether host genetic factors are involved in the onset of hepatitis C virus (HCV)-related mixed cryoglobulinemia (MC). We studied 25 consecutive patients presenting with a full-blown clinical picture of MC by physical examination, blood chemistry, assessment of cryoglobulins and their composition, nonorgan-specific autoantibodies, antibodies to HCV, serum HCV RNA, and HLA polymorphism. Biopsies of liver, bone marrow, and minor salivary glands were also performed in a number of patients. HLA results were compared with those of normal controls and patients with chronic HCV infection without MC and negative for autoimmune phenomena (pathological controls). Type II MC was found in 14 of 25 patients (56%), and type III MC was found in the remaining 11 (44%). All patients were positive for antibodies to HCV and/or serum HCV RNA. HLA-B8 was found in 40% (10 of 25) of patients compared with 10.1% (38 of 377) of normal controls (P = .00003, Pcorrected = .0005, relative risk [RR] 5.9) and 6.7% (2 of 30) of pathological controls (P = .007, Pcorrected = not significant). As for class II HLA molecules, only DR3 was significantly more frequent in MC patients (40%, 10 of 25) than in normal controls (15.1%, 57 of 377; P = .003, Pcorrected= .03, RR 3.7). Odds ratio (OR) for the risk of developing MC was calculated in patients positive for B8 and/or DR3, and the highest OR (8.2) was observed in individuals possessing both. The results suggest that the development of HCV-related MC is associated with HLA-B8 and DR3 markers.

Description: Our aim was to investigate whether host genetic factors are involved in the onset of hepatitis C virus (HCV)-related mixed cryoglobulinemia (MC). We studied 25 consecutive patients presenting with a full-blown clinical picture of MC by physical examination, blood chemistry, assessment of cryoglobulins and their composition, nonorgan-specific autoantibodies, antibodies to HCV, serum HCV RNA, and HLA polymorphism. Biopsies of liver, bone marrow, and minor salivary glands were also performed in a number of patients. HLA results were compared with those of normal controls and patients with chronic HCV infection without MC and negative for autoimmune phenomena (pathological controls). Type II MC was found in 14 of 25 patients (56%), and type III MC was found in the remaining 11 (44%). All patients were positive for antibodies to HCV and/or serum HCV RNA. HLA-B8 was found in 40% (10 of 25) of patients compared with 10.1% (38 of 377) of normal controls (P = .00003, Pcorrected = .0005, relative risk [RR] 5.9) and 6.7% (2 of 30) of pathological controls (P = .007, Pcorrected = not significant). As for class II HLA molecules, only DR3 was significantly more frequent in MC patients (40%, 10 of 25) than in normal controls (15.1%, 57 of 377; P = .003, Pcorrected= .03, RR 3.7). Odds ratio (OR) for the risk of developing MC was calculated in patients positive for B8 and/or DR3, and the highest OR (8.2) was observed in individuals possessing both. The results suggest that the development of HCV-related MC is associated with HLA-B8 and DR3 markers.

Description: Abstract 1670 Among genes that are supposed to be involved in altered molecular pathways leading to leukemogenesis, the CDKN2A/B locus is particularly noteworthy since it encodes for the INK4-class cyclin dependent kinase inhibitors p15 INK4B, p16 INK4A and p14 ARF, which act as tumor suppressors. The CDKN2A/B locus has been found to be inactivated in several haeamatologic malignancies mainly due to deletion, aberrant repression or epigenetic silencing, whereas little is known about the potential role of its single nucleotide polymorphisms (SNPs) in leukemia susceptibility. To investigate whether polymorphisms within this broad genomic region can correlate with increased susceptibility to haeamatologic malignancies, an association study was performed by genotyping 23 SNPs spanning the MTAP, CDKN2A/B and CDKN2BAS loci, as well as relative intergenic regions, in a case-control cohort made up of 332 samples: 149 leukemia patients, including Philadelphia positive (Ph+) ALL (n=92) and acute myeloid leukemia (AML) samples (n=57), and 183 unrelated healthy controls. Ph+ ALL patients showed a median age of 52 years (18-78 years); 24 cases (26%) expressed the p210 oncoprotein, 62 (67%) the p190 and 6 (7%) both the proteins. AML patients showed a median age of 53 years (21-71 years) and they included FAB-M0, M1, M2, M3, M4, M5, miscellaneous cytogenetic abnormalities and normal karyotype subtypes. 6 SNPs were selected on the basis of their previous association with several diseases, such as coronary artery disease (rs2891168, rs518394, rs564398, rs10757278), type 2 diabetes mellitus (rs564398), frailty (rs2811712). The remaining 17 SNPs were selected among those included in the Affymetrix Genome-Wide Human SNP Array 6.0 to deepen the SNPs coverage for the examined region. Genotyping was performed using iPLEX Gold technology and MassARRAY high-throughput DNA analysis with Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (Sequenom, Inc., San Diego, CA). Furthermore, all leukemia samples were also previously genotyped using the GeneChip® Human Mapping 250K NspI and Genome-Wide Human SNP 6.0 (Affymetrix). A total of 17 SNPs, spanning the 9p genomic interval that encompasses the MTAP, CDKN2A/B and CDKN2BAS loci, were successfully genotyped and used for investigating their potential associations with the leukemia phenotypes. Five SNPs (rs1012713, rs10965179, rs34011899, rs3731232, rs3218010) with Minor Allele Frequency (MAF) 20% missing call rates, were instead excluded from the association analysis. Potential population stratification affecting the control sample was ruled out as its genotypes distribution satisfies the Hardy-Weinberg equilibrium criterion. Among the 17 SNPs, rs564398, mapping to the CDKN2BAS locus that encodes for ANRIL antisense non-coding RNA, showed a statistically significant correlation with the ALL phenotype, with a risk pattern that was compatible with an overdominant model of disease susceptibility and an Odd Ratio (OR) of 2 (95% CI, 1.20 to 3.33; p= 7.1 × 10-3). Since a co-ordinated regulation of ANRIL and p14/ARF, p16/CDKN2A, p15/CDKN2B transcription has been already observed in both physiologic and pathologic conditions, we hypothesized that rs564398 association reflects a condition of high linkage disequilibrium between such polymorphism and a causative variant that is able to alter CDKN2A/B expression profiles by changing ANRIL dosage, thus leading to abnormal proliferative boosts and consequent increased ALL susceptibility. Supported by European LeukemiaNet, AIL, AIRC, FIRB 2006, PRIN 2008, Ateneo RFO grants, Project of integrated program (PIO), Programma di Ricerca Regione – Università 2007 – 2009. Disclosures: Baccarani: Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Martinelli:Novartis: Consultancy, Honoraria; BMS: Honoraria; Pfizer: Consultancy.