Prognostic impact of bone marrow fibrosis in primary myelodysplastic syndromes

La mielofibrosis (MF) se observa en el 10-20% de los pacientes con síndrome mielodisplásico (SMD). Su presencia es reconocida como un hallazgo histológico adverso asociado a curso agresivo, fallo medular temprano, sobrevida acortada y evolución leucémica.El objetivo fue examinar la influencia de la MF (MF ≥1) en la sobrevida global (SG) y su asociacióncon variables clínicas e histopatológicas.Se identificaron 468 pacientes con SMD incluidos en el Registro Argentino de SMD de 2007 a 2017.La mediana de SG del subgrupo MF ≥1 fue de 20,1 meses (IC 95%: 10,1-30,0) versus 67,6 meses (IC95% 45,1-90,3) del subgrupo MF-0 (p2 (HR 2,07, 95% IC 1,44-2,96; p5% (HR 2,94,IC 95% 2,06-4,20; p3 (HR 2,17; IC 95%: 1,48-3,19;p1000 ug/L (OR 3,41; p= 0,006) y la localización eritroide atípica (OR 2,65; p=0,004) se asociaron significativamente con la presencia de MF ≥1.Los resultados destacan la presencia de MF ≥1 como un factor pronóstico adverso para la supervivencia en SMD, asociado con hiperferritinemia y alteración de la localización de la progenie eritroide en la MO.Myelofibrosis (MF) is observed in 10-20% of patients with myelodysplastic syndrome (MDS). The presence of MF has been recognized as an adverse histological finding associated with an aggressive course including early bone marrow (BM) failure, shortened survival and leukemic evolution. The aim of this study was to examine the influence of the myelofibrosis (MF ≥1) in the overall survival (OS) and its association with clinical and histopathologic variables. We identified 468 MDS patients who were included in the Argentinian Registry of MDS from 2007 to 2017. The median OS for the MF≥1 subgroup was 20.1 months (95% CI 10.1-30.0) versus 67.6 months (95% CI 45.1-90.3) for the MF-0 subgroup (p2 (HR 2.07, 95% CI 1.44-2.96; p5% (HR 2.94, 95% CI 2.06-4.20; p3 (HR 2.17, 95% CI 1.48- 3.19; p 1000 ug/L (OR 3.41; p=0.006) and the atypical erythroid localization (OR 2.65; p=0.004) were significantly associated with the presence of MF ≥1. Our results highlight the presence of any grade of myelofibrosis as an independent adverse prognostic factor for survival in MDS, associated with higher ferritin level and abnormal erythroid localization in the BM.Fil: Russo, Maria Florencia. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal General de Agudos Paroissien (higa Paroissien); ArgentinaFil: Belli, Carolina Bárbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Enrico, Alicia. Hospital Italiano de La Plata; ArgentinaFil: Arbelbide, Jorge. Hospital Italiano; ArgentinaFil: Narbaitz, Marina. Academia Nacional de Medicina de Buenos Aires; ArgentinaFil: de Dios Soler, Marcela. Hospital Municipal de Oncologia Maria Curie ; Gobierno de la Ciudad Autonoma de Buenos Aires;Fil: Garcia Rivello, Hernan Jorge. Hospital Italiano; ArgentinaFil: Martin, Carlos. Hospital Italiano de La Plata; ArgentinaFil: Iastrebner, Marcelo. Sanatorio Sagrado Corazón; ArgentinaFil: Gonzalez, Jacqueline. Gobierno de la Ciudad Autónoma de Buenos Aires. Hospital General de Agudos Carlos Durand; ArgentinaFil: Rosenhain, Mariana. Hospital General de Agudos Dr. Enrique Tornú; ArgentinaFil: Alfonso, Graciela. Hospital Nacional Profesor Alejandro Posadas; ArgentinaFil: Kornblihtt, Laura Inés. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Perusini, Agustina. Hospital Italiano; ArgentinaFil: Lazzarino, Carolina. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal General de Agudos Paroissien (higa Paroissien); Argentin

Mixed model approaches for the identification of QTLs within a maize hybrid breeding program

Two outlines for mixed model based approaches to quantitative trait locus (QTL) mapping in existing maize hybrid selection programs are presented: a restricted maximum likelihood (REML) and a Bayesian Markov Chain Monte Carlo (MCMC) approach. The methods use the in-silico-mapping procedure developed by Parisseaux and Bernardo (2004) as a starting point. The original single-point approach is extended to a multi-point approach that facilitates interval mapping procedures. For computational and conceptual reasons, we partition the full set of relationships from founders to parents of hybrids into two types of relations by defining so-called intermediate founders. QTL effects are defined in terms of those intermediate founders. Marker based identity by descent relationships between intermediate founders define structuring matrices for the QTL effects that change along the genome. The dimension of the vector of QTL effects is reduced by the fact that there are fewer intermediate founders than parents. Furthermore, additional reduction in the number of QTL effects follows from the identification of founder groups by various algorithms. As a result, we obtain a powerful mixed model based statistical framework to identify QTLs in genetic backgrounds relevant to the elite germplasm of a commercial breeding program. The identification of such QTLs will provide the foundation for effective marker assisted and genome wide selection strategies. Analyses of an example data set show that QTLs are primarily identified in different heterotic groups and point to complementation of additive QTL effects as an important factor in hybrid performance

QTL linkage analysis of connected populations using ancestral marker and pedigree information

The common assumption in quantitative trait locus (QTL) linkage mapping studies that parents of multiple connected populations are unrelated is unrealistic for many plant breeding programs. We remove this assumption and propose a Bayesian approach that clusters the alleles of the parents of the current mapping populations from locus-specific identity by descent (IBD) matrices that capture ancestral marker and pedigree information. Moreover, we demonstrate how the parental IBD data can be incorporated into a QTL linkage analysis framework by using two approaches: a Threshold IBD model (TIBD) and a Latent Ancestral Allele Model (LAAM). The TIBD and LAAM models are empirically tested via numerical simulation based on the structure of a commercial maize breeding program. The simulations included a pilot dataset with closely linked QTL on a single linkage group and 100 replicated datasets with five linkage groups harboring four unlinked QTL. The simulation results show that including parental IBD data (similarly for TIBD and LAAM) significantly improves the power and particularly accuracy of QTL mapping, e.g., position, effect size and individuals’ genotype probability without significantly increasing computational demand

Impacto pronóstico de la mielofibrosis en pacientes con síndromes mielodisplásicos y leucemia mielomonocítica crónica

La mielofibrosis (MF) se observa en el 10-20% de los pacientes con síndrome mielodisplásico (SMD). Su presencia es reconocida como un hallazgo histológico adverso asociado a curso agresivo, fallo medular temprano, sobrevida acortada y evolución leucémica. El objetivo fue examinar la influencia de la MF (MF ≥1) en la sobrevida global (SG) y su asociación con variables clínicas e histopatológicas. Se identificaron 468 pacientes con SMD incluidos en el Registro Argentino de SMD de 2007 a 2017. La mediana de SG del subgrupo MF ≥1 fue de 20,1 meses (IC 95%: 10,1-30,0) versus 67,6 meses (IC 95% 45,1-90,3) del subgrupo MF-0 (p&lt;0,001). Parámetros como la MF ≥1 (HR 1,46, 95% IC 1,06- 2,03; p=0,020), estado funcional &gt;2 (HR 2,07, 95% IC 1,44-2,96; p&lt;0,001), hemoglobina &lt;10 gr/dL (HR 1,64, IC 95% 1,16-2,32; p=0,005), recuento de plaquetas &lt;100.000/μL (HR 1,94, IC 95% 1,42-2,65; p&lt;0,001), cariotipos adversos (HR 1,86, IC 95% 1,32-2,63; p&lt;0,001), blastos en MO &gt;5% (HR 2,94, IC 95% 2,06-4,20; p&lt;0,001) y el índice de comorbilidades de Charlson &gt;3 (HR 2,17; IC 95%: 1,48-3,19; p&lt;0,001) se asociaron de forma independiente a SG reducida. Mientras que la ferritina &gt;1000 ug/L (OR 3,41; p= 0,006) y la localización eritroide atípica (OR 2,65; p=0,004) se asociaron significativamente con la presencia de MF ≥1. Los resultados destacan la presencia de MF ≥1 como un factor pronóstico adverso para la supervivencia en SMD, asociado con hiperferritinemia y alteración de la localización de la progenie eritroide en la MO.</jats:p