Granular cell tumors (GCTs) are rare tumors that can arise in multiple anatomical locations, and are characterized by abundant intracytoplasmic granules. The genetic drivers of GCTs are currently unknown. Here, we apply whole-exome sequencing and targeted sequencing analysis to reveal mutually exclusive, clonal, inactivating somatic mutations in the endosomal pH regulators ATP6AP1 or ATP6AP2 in 72% of GCTs. Silencing of these genes in vitro results in impaired vesicle acidification, redistribution of endosomal compartments, and accumulation of intracytoplasmic granules, recapitulating the cardinal phenotypic characteristics of GCTs and providing a novel genotypic–phenotypic correlation. In addition, depletion of ATP6AP1 or ATP6AP2 results in the acquisition of oncogenic properties. Our results demonstrate that inactivating mutations of ATP6AP1 and ATP6AP2 are likely oncogenic drivers of GCTs and underpin the genesis of the intracytoplasmic granules that characterize them, providing a genetic link between endosomal pH regulation and tumorigenesis.

The detection of germline mutations in BRCA1 and BRCA2 is essential to the formulation of clinical management strategies, and in Brazil, there is limited access to these services, mainly due to the costs/availability of genetic testing. Aiming at the identification of recurrent mutations that could be included in a low-cost mutation panel, used as a first screening approach, we compiled the testing reports of 649 probands with pathogenic/likely pathogenic variants referred to 28 public and private health care centers distributed across 11 Brazilian States. Overall, 126 and 103 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-six novel variants were reported from both genes, and BRCA2 showed higher mutational heterogeneity. Some recurrent mutations were reported exclusively in certain geographic regions, suggesting a founder effect. Our findings confirm that there is significant molecular heterogeneity in these genes among Brazilian carriers, while also suggesting that this heterogeneity precludes the use of screening protocols that include recurrent mutation testing only. This is the first study to show that profiles of recurrent mutations may be unique to different Brazilian regions. These data should be explored in larger regional cohorts to determine if screening with a panel of recurrent mutations would be effective.

Serum miR-21 and miR-34a are potentially useful diagnostic biomarkers of PDAC. In addition, our results suggest that these miRNAs are not differentially expressed in saliva, making them unsuitable for use as noninvasive biomarkers for diagnostic purposes.

TP53 mutation is a common event in many cancers, including pancreatic adenocarcinoma, where it occurs in 50-70 % of cases. In an effort to reactivate mutant p53 protein, several new drugs are being developed, including PRIMA-1 and PRIMA-1(Met)/APR-246 (p53 reactivation and induction of massive apoptosis). PRIMA-1 has been shown to induce apoptosis in tumor cells by reactivating p53 mutants, but its effect in pancreatic cancer remains unclear. Here we investigated the effects of PRIMA-1 on cell viability, cell cycle and expression of p53-regulated proteins in PANC-1 and BxPC-3 (mutant TP53), and CAPAN-2 (wild-type TP53) pancreatic cell lines. Treatment with PRIMA-1 selectively induced apoptosis and cell cycle arrest in p53 mutant cells compared to CAPAN-2 cells. The growth suppressive effect of PRIMA-1 was markedly reduced in p53 mutant cell lines transfected with p53 siRNA, supporting the role of mutant p53 in PRIMA-1 induced cell death. Moreover, treatment with the thiol group donor N-acetylcysteine completely blocked PRIMA-1-induced apoptosis and reinforced the hypothesis that thiol modifications are important for PRIMA-1 biological activity. In combination treatments, PRIMA-1 enhanced the anti-tumor activity of several chemotherapic drugs against pancreatic cancer cells and also exhibited a pronounced synergistic effect in association with the Mdm2 inhibitor Nutlin-3. Taken together, our data indicate that PRIMA-1 induces apoptosis in p53 mutant pancreatic cancer cells by promoting the re-activation of p53 and inducing proapoptotic signaling pathways, providing in vitro evidence for a potential therapeutic approach in pancreatic cancer.

We validated the presence of IDH2 R172 hotspot mutations and PIK3CA hotspot mutations in 100% and 67% BPTCs tested, respectively, and documented absence of IDH2 R172 mutations in SPCs. These findings confirm the genotypical-phenotypical correlation reported previously in BPTC, which constitutes an entity distinct from conventional SPC.

BackgroundGermline pathogenic variants in BRCA1 and BRCA2 (BRCA) are the main cause of Hereditary Breast and Ovarian Cancer syndrome (HBOC).MethodsIn this study we evaluated the mutational profile and prevalence of BRCA pathogenic/likely pathogenic variants among probands fulfilling the NCCN HBOC testing criteria. We characterized the clinical profile of these individuals and explored the performance of international testing criteria.ResultsA pathogenic/likely pathogenic variant was detected in 19.1% of 418 probands, including seven novel frameshift variants. Variants of uncertain significance were found in 5.7% of individuals. We evaluated 50 testing criteria and mutation probability algorithms. There was a significant odds-ratio (OR) for mutation prediction (p ≤ 0.05) for 25 criteria; 14 of these had p ≤ 0.001. Using a cutoff point of four criteria, the sensitivity is 83.8%, and the specificity is 53.5% for being a carrier. The prevalence of pathogenic/likely pathogenic variants for each criterion ranged from 22.1% to 55.6%, and criteria with the highest ORs were those related to triple-negative breast cancer or ovarian cancer.ConclusionsThis is the largest study of comprehensive BRCA testing among Brazilians to date, and the first to analyze clinical criteria for genetic testing. Several criteria that are not included in the NCCN achieved a higher predictive value. Identification of the most informative criteria for each population will assist in the development of a rational approach to genetic testing, and will enable the prioritization of high-risk individuals as a first step towards offering testing in low-income countries.

BACKGROUND: Pediatric cancers are a feature in patients with Li-Fraumeni syndrome and its variant Li-Fraumeni-like syndrome (LFS=LFL). To the best of the authors' knowledge, TP53 germline mutations are currently the only molecular defect known to be associated with this disease. Recently, a specific germline mutation in this gene, p.R337H, has been reported at a high prevalence in Brazil. METHODS: The prevalence of LFS=LFL was investigated in children with cancer who were diagnosed with tumors on the LFS=LFL spectrum and in a small consecutive series of controls without cancer. The prevalence of the germline p.R337H mutation and of other germline TP53 mutations was investigated in a general group of children with cancer and exclusively in children fulfilling the clinical criteria for LFS=LFL, respectively. RESULTS: Among the 65 children without cancer, 1.5% had a family history of LFL whereas of the 292 children with cancer, 25.3% had a family history of LFL (P <.001). Screening for the p.R337H mutation identified 11 carriers (3.7%), 9 of whom were diagnosed with adrenocortical carcinomas (ACC) and 2 of whom were diagnosed with choroid plexus carcinomas. One of the ACC probands was homozygous mutant. The Brazilian founder haplotype and loss of heterozygosity at the p.R337H locus were present in all carriers. In addition, direct sequencing of the entire TP53 coding region and gene rearrangement analysis of probands fulfilling the criteria for LFL (Eeles 2 criteria, Birch and=or Chompret criteria) and who were negative for the p.R337H mutation revealed a DNA-binding domain pathogenic mutation, p.G245S, in 1 child. CONCLUSIONS: TP53 p.R337H testing should be offered to Brazilian children diagnosed with ACC and choroid plexus carcinoma. A significant percentage of children with cancer in southern Brazil fulfill the criteria for LFL and should be referred for genetic risk assessment. Cancer 2013;119:4341-9. V C 2013 American Cancer Society.KEYWORDS: childhood cancer, Li-Fraumeni syndrome, Li-Fraumeni-like syndrome, TP53 mutations, TP53 p.R337H mutation. INTRODUCTIONPediatric cancer is one of the more frequent causes of nontraumatic deaths in children, representing 1% to 3% of all cancer diagnoses worldwide. [1][2][3][4][5] The Brazilian National Cancer Institute estimates that approximately 384,340 new cancer diagnoses will have been made in Brazil in 2012, including 11,530 (3%) diagnosed in children and adolescents aged < 19 years. 5 Childhood cancers that arise within the context of a genetic predisposition are rare events, and are estimated to account for approximately 5% to 10% of all pediatric cancer cases. 5 However, with increased awareness of cancer family history and advanced technologies in mutation detection, this percentage will likely increase, 6 facilitating the presymptomatic identification of high-risk individuals and ultimately decreasing cancer-related mortality in this setting.Childhood cancers are a common feature in patients with Li-Fraumeni syndrome and its variant Li-Fraumeni-like syndrome (LFS...

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