Wilson disease (WD) is a copper metabolism disorder characterized by hepatic and/or neurological damage. More than 200 mutations in the ATP7B gene causing this autosomal recessive defect have been reported. In certain populations, a high prevalence of particular mutations allows rapid screening and diagnosis of the disease. We identified the ATP7B alterations in Spanish patients with WD. Mutations in the ATP7B gene were analysed in a total of 64 individuals from 40 different WD families by PCR amplification, single-strand conformation polymorphism (SSCP) analysis and sequencing. Twenty-one different ATP7B gene mutations were identified, eight of which were novel. 74% of the disease alleles were characterized among the 40 unrelated probands. We identified a prevalent mutation in our population (Met645Arg), present in 55% of this 40 patients. The frequency of the remaining ATP7B alterations was low. In addition, 17 different polymorphic variants were found. There is remarkable allele heterogeneity in WD in the Spanish population. Nevertheless, SSCP screening for the most frequent mutations in our population is feasible and leads to the detection of about 74% of the mutated chromosomes. Molecular diagnosis of WD is very useful in clinical practice to confirm or support clinical suspicion.

Circulating tumor DNA (ctDNA) has emerged as a promising non-invasive source to characterize genetic alterations related to the tumor. Upper gastrointestinal cancers, including gastroesophageal adenocarcinoma (GEC), biliary tract cancer (BTC) and pancreatic ductal adenocarcinoma (PADC) are poor prognostic malignancies, usually diagnosed at advanced stages when no longer amenable to surgical resection and show a poor prognosis even for resected patients. In this sense, ctDNA has emerged as a promising non-invasive tool with different applications, from early diagnosis to molecular characterization and follow-up of tumor genomic evolution. In this manuscript, novel advances in the field of ctDNA analysis in upper gastrointestinal tumors are presented and discussed. Overall, ctDNA analyses can help in early diagnosis, outperforming current diagnostic approaches. Detection of ctDNA prior to surgery or active treatment is also a prognostic marker that associates with worse survival, while ctDNA detection after surgery is indicative of minimal residual disease, anticipating in some cases the imaging-based detection of progression. In the advanced setting, ctDNA analyses characterize the genetic landscape of the tumor and identify patients for targeted-therapy approaches, and studies show variable concordance levels with tissue-based genetic testing. In this line, several studies also show that ctDNA serves to follow responses to active therapy, especially in targeted approaches, where it can detect multiple resistance mechanisms. Unfortunately, current studies are still limited and observational. Future prospective multi-center and interventional studies, carefully designed to assess the value of ctDNA to help clinical decision-making, will shed light on the real applicability of ctDNA in upper gastrointestinal tumor management. This manuscript presents a review of the evidence available in this field up to date.

SALAS-GÓMEZ, D. Mutational evaluation of TP53 gene in the canine hepatocellular carcinoma: a comparative approach. [Avaliação mutacional do gene TP53 no carcinoma hepatocelular em cães: uma abordagem comparativa]. 2019. 78f.

The liver is a prime target for in vivo gene therapies using recombinant adeno-associated viral vectors (rAAV). Multiple clinical trials have been undertaken for this target in the past 15 years, however we are still to see market approval of the first liver-targeted AAV-based gene therapy. Inefficient expression of the therapeutic transgene, vector-induced liver toxicity and capsid, and/or transgene-mediated immune responses reported at high vector doses are the main challenges to date. One of the contributing factors to the insufficient clinical outcomes, despite highly encouraging preclinical data, is the lack of robust, biologically- and clinically-predictive preclinical models. To this end, this study reports findings of a functional evaluation of six AAV vectors in twelve preclinical models of the human liver, with the aim to uncover which model is the most relevant for the selection of AAV capsid variant for safe and efficient transgene delivery to primary human hepatocytes. The results, generated by studies in models ranging from immortalized cells, iPSC-derived and primary hepatocytes, and primary human hepatic organoids to in vivo models, increased our understanding of the strengths and weaknesses of each system. This should allow the development of novel gene therapies targeting the human liver.