The pan-cancer analysis of whole genomes The expansion of whole-genome sequencing studies from individual ICGC and TCGA working groups presented the opportunity to undertake a meta-analysis of genomic features across tumour types. To achieve this, the PCAWG Consortium was established. A Technical Working Group implemented the informatics analyses by aggregating the raw sequencing data from different working groups that studied individual tumour types, aligning the sequences to the human genome and delivering a set of high-quality somatic mutation calls for downstream analysis (Extended Data Fig. 1). Given the recent meta-analysis

Tumor cells typically resist programmed cell death (apoptosis) induced by death receptors. Activated death receptors evoke Bax conformational change, cytochrome c release, and cell death. We report that the tumor suppressor gene RASSF1A is required for death receptor-induced Bax conformational change and apoptosis. TNFalpha or TRAIL stimulation induced recruitment of RASSF1A and MAP-1 to receptor complexes and promoted complex formation between RASSF1A and the BH3-like protein MAP-1. Normally, MAP-1 is inhibited by an intramolecular interaction. RASSF1A/MAP-1 binding relieved this inhibitory interaction, resulting in MAP-1 association with Bax. Deletion of the RASSF1A gene or short hairpin silencing of either RASSF1A or MAP-1 expression blocked MAP-1/Bax interaction, Bax conformational change and mitochondrial membrane insertion, cytochrome c release, and apoptosis in response to death receptors. Our findings identify RASSF1A and MAP-1 as important components between death receptors and the apoptotic machinery and reveal a potential link between tumor suppression and death receptor signaling.

The RAS association domain family 1A (RASSF1A) gene is silenced by DNA methylation in over 50% of all solid tumors of different histological types. However, the biochemical function of the RASSF1A protein is unknown. We show that RASSF1A colocalizes with microtubules in interphase and decorates spindles and centrosomes during mitosis. RASSF1A has a strong cytoprotective activity against the microtubule-destabilizing drug nocodazole, and against cold-treatment in vivo. Conversely, loss of RASSF1 in RASSF1 À/À mouse embryonic fibroblasts renders the cells more sensitive to nocodazole-induced depolymerization of microtubules. The domain required for both microtubule association and stabilization was mapped to a 169 amino-acid fragment that contains the RAS association domain. Overexpression of RASSF1A induces mitotic arrest at metaphase with aberrant mitotic cells reminiscent of such produced by the microtubule-stabilizing drug paclitaxel (taxol), including monopolar spindles, or complete lack of a mitotic spindle. Altered microtubule stability in cells lacking RASSF1A is likely to affect spindle assembly and chromosome attachment, processes that need to be carefully controlled to protect cells from genomic instability and transformation. In addition, knowledge of the microtubule-targeting function of RASSF1 may aid in the development of new anticancer drugs.

The Ras Association Domain Family 1A (RASSF1A) gene is one of the most frequently silenced genes in human cancer. RASSF1A has been shown to interact with the proapoptotic kinase MST1. Recent work in Drosophila has led to the discovery of a new tumor-suppressor pathway involving the Drosophila MST1 and MST2 ortholog, Hippo, as well as the Lats/Warts serine/threonine kinase and a protein named Salvador (Sav). Little is known about this pathway in mammalian cells. We report that complexes consisting of RASSF1A, MST2, WW45 (the human ortholog of Sav), and LATS1 exist in human cells. MST2 enhances the RASSF1A-WW45 interaction, which requires the C-terminal SARAH domain of both proteins. Components of this complex are localized at centrosomes and spindle poles from interphase to telophase and at the midbody during cytokinesis. Both RASSF1A and WW45 activate MST2 by promoting MST2 autophosphorylation and LATS1 phosphorylation. Mitosis is delayed in Rassf1a(-/-) mouse embryo fibroblasts and frequently results in cytokinesis failure, similar to what has been observed for LATS1-deficient cells. RASSF1A, MST2, or WW45 can rescue this defect. The complex of RASSF1A, MST2, WW45, and LATS1 consists of several tumor suppressors, is conserved in mammalian cells, and appears to be involved in controlling mitotic exit.

In quiescent cells, cdc2 mRNA is almost undetectable. Stimulation of cells to reenter the cell cycle results in induction of cdc2 expression, beginning at the G1-to-S transition and reaching maximum levels during late S and G2 phases. To investigate cdc2 transcriptional regulation throughout cell cycle progression, we monitored protein-DNA interactions by in vivo footprinting along 800 bp of the human cdc2 promoter in quiescent fibroblasts and at different time points following serum stimulation. We found 11 in vivo protein-binding sites, but no protein binding was observed at a high-affinity E2F site that had previously been implicated in cdc2 regulation. Nine of the identified in vivo binding sites (among them were two inverted CCAAT boxes, two Sp1 sites, and one ets-2 site) bind transcription factors constitutively throughout the cell cycle. However, at two elements located at positions -60 and -20 relative to the transcription start site, the binding pattern changes significantly as the cells are entering S phase. A G0- and G1-specific protein complex disappears at the -20 element at the beginning of S phase. This sequence deviates at one base position from known E2F consensus binding sites. We found that the major E2F activity in human fibroblasts contains E2F-4 and p130. The -20 element of the cdc2 gene specifically interacts with a subset of E2F-4-p130 complexes present in G0 cells but does not interact with S-phase-specific E2F complexes. Transient-transfection experiments with wild-type and mutant cdc2 promoter constructs indicate that the -20 element is involved in suppressing cdc2 activity in quiescent cells. We suggest that the presence of the p130-E2F-4 complex in G0/G1 blocks access of components of the basal transcription machinery or prevents transaction by the constitutively bound upstream activator proteins.

Smoking is a major risk factor for a variety of diseases, including cancer and immune-mediated inflammatory diseases. Tobacco smoke contains a mixture of chemicals, including a host of reactive oxygen-and nitrogen species (ROS and RNS), among others, that can damage cellular and sub-cellular targets, such as lipids, proteins, and nucleic acids. A growing body of evidence supports a key role for smoking-induced ROS and the resulting oxidative stress in inflammation and carcinogenesis. This comprehensive and up-to-date review covers four interrelated topics, including 'smoking', 'oxidative stress', 'inflammation', and 'cancer'. The review discusses each of the four topics, while exploring the intersections among the topics by highlighting the macromolecular damage attributable to ROS. Specifically, oxidative damage to macromolecular targets, such as lipid peroxidation, post-translational modification of proteins, and DNA adduction, as well as enzymatic and non-enzymatic antioxidant defense mechanisms, and the multi-faceted repair pathways of oxidized lesions are described. Also discussed are the biological consequences of oxidative damage to macromolecules if they evade the defense mechanisms and/or are not repaired properly or in time. Emphasis is placed on the genetic-and epigenetic alterations that may lead to transcriptional deregulation of functionally-important genes and disruption of regulatory elements. Smoking-associated oxidative stress also activates the inflammatory response pathway, which triggers a cascade of events of which ROS production is an initial yet indispensable step. The release of ROS at the site of damage and inflammation helps combat foreign pathogens and restores the injured tissue, while simultaneously increasing the burden of oxidative stress. This creates a vicious cycle in which smoking-related oxidative stress causes inflammation, which in turn, results in further generation of ROS, and potentially increased oxidative damage to macromolecular targets that may lead to cancer initiation and/or progression.

Introduction Aberrant methylation of CpG islands is a hallmark of cancer and occurs at an early stage in breast tumorigenesis. However, its impact on tumor development is not fully determined, and its potential as a diagnostic biomarker remains to be validated. Methylation profiling of invasive breast carcinoma has been largely explored. Conversely, very little and sparse information is available on early-stage breast cancer. To gain insight into the epigenetic switches that may promote and/ or contribute to the initial neoplastic events during breast carcinogenesis, we have analyzed the DNA methylation profile of ductal carcinoma in situ, a premalignant breast lesion with a great potential to progress toward invasive carcinoma.

PurposeBRCA1/2 mutations increase the risk of breast and prostate cancer in men. Common genetic variants modify cancer risks for female carriers of BRCA1/2 mutations. We investigated—for the first time to our knowledge—associations of common genetic variants with breast and prostate cancer risks for male carriers of BRCA1/2 mutations and implications for cancer risk prediction.Materials and MethodsWe genotyped 1,802 male carriers of BRCA1/2 mutations from the Consortium of Investigators of Modifiers of BRCA1/2 by using the custom Illumina OncoArray. We investigated the combined effects of established breast and prostate cancer susceptibility variants on cancer risks for male carriers of BRCA1/2 mutations by constructing weighted polygenic risk scores (PRSs) using published effect estimates as weights.ResultsIn male carriers of BRCA1/2 mutations, PRS that was based on 88 female breast cancer susceptibility variants was associated with breast cancer risk (odds ratio per standard deviation of PRS, 1.36; 95% CI, 1.19 to 1.56; P = 8.6 × 10−6). Similarly, PRS that was based on 103 prostate cancer susceptibility variants was associated with prostate cancer risk (odds ratio per SD of PRS, 1.56; 95% CI, 1.35 to 1.81; P = 3.2 × 10−9). Large differences in absolute cancer risks were observed at the extremes of the PRS distribution. For example, prostate cancer risk by age 80 years at the 5th and 95th percentiles of the PRS varies from 7% to 26% for carriers of BRCA1 mutations and from 19% to 61% for carriers of BRCA2 mutations, respectively.ConclusionPRSs may provide informative cancer risk stratification for male carriers of BRCA1/2 mutations that might enable these men and their physicians to make informed decisions on the type and timing of breast and prostate cancer risk management.