Diamond-Blackfan Anemia (DBA) is characterized by a defect of erythroid progenitors and, clinically, by anemia and malformations. DBA exhibits an autosomal dominant pattern of inheritance with incomplete penetrance. Currently nine genes, all encoding ribosomal proteins (RP), have been found mutated in approximately 50% of patients. Experimental evidence supports the hypothesis that DBA is primarily the result of defective ribosome synthesis. By means of a large collaboration among six centers, we report here a mutation update that includes nine genes and 220 distinct mutations, 56 of which are new. The DBA Mutation Database now includes data from 355 patients. Of those where inheritance has been examined, 125 patients carry a de novo mutation and 72 an inherited mutation. Mutagenesis may be ascribed to slippage in 65.5% of indels, whereas CpG dinucleotides are involved in 23% of transitions. Using bioinformatic tools we show that gene conversion mechanism is not common in RP genes mutagenesis, notwithstanding the abundance of RP pseudogenes. Genotype–phenotype analysis reveals that malformations are more frequently associated with mutations in RPL5 and RPL11 than in the other genes. All currently reported DBA mutations together with their functional and clinical data are included in the DBA Mutation Database.

Diamond-Blackfan anemia (DBA) typically presents with red blood cell aplasia that usually manifests in the first year of life. The only gene currently known to be mutated in DBA encodes ribosomal protein S19 (RPS19). Previous studies have shown that the yeast RPS19 protein is required for a specific step in the maturation of 40S ribosomal subunits. Our objective here was to determine whether the human RPS19 protein functions at a similar step in 40S subunit maturation. Studies where RPS19 expression is reduced by siRNA in the hematopoietic cell line, TF-1, show that human RPS19 is also required for a specific step in the maturation of 40S ribosomal subunits. This maturation defect can be monitored by studying rRNA-processing intermediates along the ribosome synthesis pathway. Analysis of these intermediates in CD34 ؊ cells from the bone marrow of patients with DBA harboring mutations in RPS19 revealed a pre-rRNA-processing defect similar to that observed in TF-1 cells where RPS19 expression was reduced. This defect was observed to a lesser extent in CD34 ؉ cells from patients with DBA who have mutations in RPS19. IntroductionDiamond-Blackfan anemia (DBA) typically presents as a red blood cell aplasia that affects children in their first year of life. In addition to anemia, patients with DBA present with a heterogeneous mixture of congenital abnormalities. 1 Craniofacial abnormalities are observed in approximately 50% of patients with DBA, while other defects, including growth failure, thumb malformation, and cardiac and urogenital defects, are observed less frequently.Approximately 25% of patients with DBA have mutations in the gene encoding ribosomal protein S19, 1 of 33 ribosomal proteins that together with 18S rRNA constitutes the 40S ribosomal subunit. [2][3][4] The etiology of the remaining cases of DBA is unknown. DBA is the first and only human disease known to be caused by mutations in a gene encoding a ribosomal protein. Interestingly, several other bone marrow (BM) failure syndromes have been linked to factors involved in ribosome synthesis. 5 These syndromes include dyskeratosis congenita (DC), cartilage hair hypoplasia (CHH), and Shwachman Diamond syndrome (SDS). The proteins and RNAs affected in these diseases include the DKC1 gene in X-linked DC, which encodes a pseudouracil synthase, 6 dyskerin involved in rRNA modification, the gene RMRP involved in CHH, which participates in rRNA processing, 7 and SBDS, the gene affected in SDS which encodes a protein thought to function in RNA metabolism. [8][9][10][11] The exact role of a defect in ribosome synthesis in each of these marrow failure syndromes is obscured by the fact that some of these proteins and RNAs are part of complexes that have multiple functions within cells. Dyskerin is a component of a number of ribonucleoprotein complexes, including telomerase, 12-14 whereas RMRP is a component of an endoribonuclease involved in mRNA decay in addition to rRNA processing. 15 The only other known function for ribosomal protein S19 (RPS19) is as a monoc...

Complex interactions between tumor and host cells regulate systemic tumor dissemination, a process that begins early at the primary tumor site and goes on until tumor cells detach themselves from the tumor mass and start migrating into the blood or lymphatic vessels. Metastatic cells colonize the target organs and are capable of surviving and growing at distant sites. In this context, osteopontin (OPN) appears to be a key determinant of the crosstalk between cancer cells and the host microenvironment, which in turn modulates immune evasion. OPN is overexpressed in several human carcinomas and has been implicated in inflammation, tumor progression, and metastasis. Thus, it represents one of the most attracting targets for cancer therapy. Within the tumor mass, OPN is secreted in various forms either by the tumor itself or by stroma cells, and it can exert either pro- or antitumorigenic effects according to the cell type and tumor microenvironment. Thus, targeting OPN for therapeutic purposes needs to take into account the heterogeneous functions of the multiple OPN forms with regard to cancer formation and progression. In this review, we will describe the role of systemic, tumor-derived, and stroma-derived OPN, highlighting its pivotal role at the crossroads of inflammation and tumor progression.

Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer caused by asbestos exposure. An inherited predisposition has been suggested to explain multiple cases in the same family and the observation that not all individuals highly exposed to asbestos develop the tumor. Germline mutations in BAP1 are responsible for a rare cancer predisposition syndrome that includes predisposition to mesothelioma. We hypothesized that other genes involved in hereditary cancer syndromes could be responsible for the inherited mesothelioma predisposition. We investigated the prevalence of germline variants in 94 cancer-predisposing genes in 93 MPM patients with a quantified asbestos exposure. Ten pathogenic truncating variants (PTVs) were identified in PALB2, BRCA1, FANCI, ATM, SLX4, BRCA2, FANCC, FANCF, PMS1 and XPC. All these genes are involved in DNA repair pathways, mostly in homologous recombination repair. Patients carrying PTVs represented 9.7% of the panel and showed lower asbestos exposure than did all the other patients (p = 0.0015). This suggests that they did not efficiently repair the DNA damage induced by asbestos and leading to carcinogenesis. This study shows that germline variants in several genes may increase MPM susceptibility in the presence of asbestos exposure and may be important for specific treatment.