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Lynch syndrome was formerly known as Hereditary Nonpolyposis Colorectal Cancer. Currently, these two nomenclatures each have their unique definitions and are no longer used interchangeably. The history of hereditary nonpolyposis colorectal cancer was first recognized formally in the literature by Henry Lynch in 1967. With advances of molecular genetics, there has been a transformation from clinical phenotype to genotype diagnostics. This has led to the ability to diagnose affected patients before they manifest with cancer, and therefore allow preventative surveillance strategies. Genotype diagnostics has shown a difference in penetrance of different cancer risks dependent on the gene containing the mutation. Surgery is recommended as prevention for some cancers; for others they are reserved for once cancer is noted. Various surveillance strategies are recommended dependent on the relative risk of cancer and the ability to intervene with surgery to impact on survival. Risk reduction through aspirin has shown some recent promise, and continues to be studied. Resumo: A síndrome de Lynch era anteriormente conhecida como “câncer colorretal hereditário não polipose”. Atualmente, essas duas nomenclaturas têm, cada uma, sua própria definição original e já não são empregadas de forma intercambiável. O histórico de câncer colorretal hereditário não polipose foi formalmente reconhecido pela primeira vez na literatura por Henry Lynch em 1967. Com os avanços da genética molecular, verificou-se uma mudança do fenótipo clínico para o diagnóstico genotípico. Esse fato levou à capacidade de diagnosticar pacientes afetados antes que o câncer se manifestasse, e, portanto, à utilização de estratégias preventivas de rastreamento. O diagnóstico genotípico mostrou a diferença na penetrância de diferentes riscos de câncer dependendo do gene que contem a mutação.A cirurgia é recomendada para a prevenção de alguns tipos de câncer; para outros, ela é reservada quando há o aparecimento da doença. Várias estratégias de rastreamento são recomendadas, dependendo do risco relativo de câncer, bem como a capacidade para intervir com a cirurgia objetivando um impacto na sobrevivência. A redução do risco através do uso de aspirina recentemente mostrou ser promissor e continua a ser estudada. Keywords: Lynch syndrome, Hereditary nonpolyposis colorectal cancer, Colorectal cancer, Amsterdam criteria, Bethesda criteria, Microsatellite instability: MSI, Immunohistochemistry: IHC, Familial cancer, Muir-Torre syndrome, Turcot syndrome, Family X, Mismatch repair, Palavras-chave: Síndrome de Lynch, Câncer colorretal hereditário sem polipose, Câncer colorretal, Critérios de, Amsterdam, Critérios de Bethesda, Instabilidade de microssatélites: MSI, Imunohistoquímica: IHQ, Câncer familial, Síndrome de, Muir-Torre Síndrome de, Turcot Família X, Reparação de incompatibilidade

9 p.-4 fig.-4 tab., Protozoans of the genus Leishmania, the pathogenic agent causing leishmaniasis, encode the family X DNA polymerase Li Pol β. Here, we report the first crystal structures of Li Pol β. Our pre- and post-catalytic structures show that the polymerase adopts the common family X DNA polymerase fold. However, in contrast to other family X DNA polymerases, the dNTP-induced conformational changes in Li Pol β are much more subtle. Moreover, pre- and post-catalytic structures reveal that Li Pol β interacts with the template strand through a nonconserved, variable region known as loop3. Li Pol β Δloop3 mutants display a higher catalytic rate, catalytic efficiency and overall error rates with respect to WT Li Pol β. These results further demonstrate the subtle structural variability that exists within this family of enzymes and provides insight into how this variability underlies the substantial functional differences among their members., This work was supported by R01-GM100021 and R00 ES015421 to MGD. AA and VL thank the Fundacion Ramon Areces and MICINN (AGL2010-21806-C02-01) for funding.

Bacillus subtilis gene yshC encodes a 64 kDa family X DNA polymerase (PolXBs), which contains all the critical residues involved in DNA and nucleotide binding, as well as those responsible for catalysis of DNA polymerization, conserved in most family X members. Biochemical analyses of the purified enzyme indicate that PolXBs is a monomeric and strictly template-directed DNA polymerase, preferentially acting on DNA structures containing gaps from one to few nucleotides and bearing a phosphate group at the 5´ end of the downstream DNA. The fact that PolXBs is able to conduct filling of a single nucleotide gap, allowing further sealing of the resulting nick by a DNA ligase points to a putative role in base excision repair during the B. subtilis life cycle., This work has been aided by the Spanish Ministry of Education and Science grants BFU 2005-00733 and Consolider-Ingenio 2010 24717, and by an Institutional grant from Fundación Ramón Areces to the Centro de Biología Molecular ‘Severo Ochoa’. B.B. is a recipient of a fellowship from Fundación Ramón Areces.