Phosphorylation of Daxx by ATM contributes to DNA damage-induced p53 activation

DAXX promotes centromeric stability independently of ATRX by preventing the accumulation of R-loop-induced DNA double-stranded breaks

Maintaining chromatin integrity at the repetitive non-coding DNA sequences underlying centromeres is crucial to prevent replicative stress, DNA breaks and genomic instability. The concerted action of transcriptional repressors, chromatin remodelling complexes and epigenetic factors controls transcription and chromatin structure in these regions. The histone chaperone complex ATRX/DAXX is involved in the establishment and maintenance of centromeric chromatin through the deposition of the histone variant H3.3. ATRX and DAXX have also evolved mutually-independent functions in transcription and chromatin dynamics. Here, using paediatric glioma and pancreatic neuroendocrine tumor cell lines, we identify a novel ATRX-independent function for DAXX in promoting genome stability by preventing transcription-associated R-loop accumulation and DNA double-strand break formation at centromeres. This function of DAXX required its interaction with histone H3.3 but was independent of H3.3 deposition and did not reflect a role in the repression of centromeric transcription. DAXX depletion mobilized BRCA1 at centromeres, in line with BRCA1 role in counteracting centromeric R-loop accumulation. Our results provide novel insights into the mechanisms protecting the human genome from chromosomal instability, as well as potential perspectives in the treatment of cancers with DAXX alterations.

ATR protects centromere identity by promoting DAXX association with PML nuclear bodies

Centromere protein A (CENP-A) defines centromere identity and nucleates kinetochore formation for mitotic chromosome segregation. Here, we show that ataxia telangiectasia and Rad3-related (ATR) kinase, a master regulator of the DNA damage response, protects CENP-A occupancy at interphase centromeres in a DNA damage-independent manner. In unperturbed cells, ATR localizes to promyelocytic leukemia nuclear bodies (PML NBs), which house the histone H3.3 chaperone DAXX (death domain-associated protein 6). We find that ATR inhibition reduces DAXX association with PML NBs, resulting in the DAXX-dependent loss of CENP-A and an aberrant increase in H3.3 at interphase centromeres. Additionally, we show that ATR-dependent phosphorylation within the C terminus of DAXX regulates CENP-A occupancy at centromeres and DAXX localization. Lastly, we demonstrate that acute ATR inhibition during interphase leads to kinetochore formation defects and an increased rate of lagging chromosomes. These findings highlight a mechanism by which ATR protects centromere identity and genome stability.

MALL, a membrane-tetra-spanning proteolipid overexpressed in cancer, is present in membraneless nuclear biomolecular condensates

Proteolipids are proteins with unusual lipid-like properties. It has long been established that PLP and plasmolipin, which are two unrelated membrane-tetra-spanning myelin proteolipids, can be converted in vitro into a water-soluble form with a distinct conformation, raising the question of whether these, or other similar proteolipids, can adopt two different conformations in the cell to adapt their structure to distinct environments. Here, we show that MALL, another proteolipid with a membrane-tetra-spanning structure, distributes in membranes outside the nucleus and, within the nucleus, in membrane-less, liquid-like PML body biomolecular condensates. Detection of MALL in one or other environment was strictly dependent on the method of cell fixation used, suggesting that MALL adopts different conformations depending on its physical environment —lipidic or aqueous— in the cell. The acquisition of the condensate-compatible conformation requires PML expression. Excess MALL perturbed the distribution of the inner nuclear membrane proteins emerin and LAP2β, and that of the DNA-binding protein BAF, leading to the formation of aberrant nuclei. This effect, which is consistent with studies identifying overexpressed MALL as an unfavorable prognostic factor in cancer, could contribute to cell malignancy. Our study establishes a link between proteolipids, membranes and biomolecular condensates, with potential biomedical implications.

USP7 Is a Master Regulator of Genome Stability

Genetic alterations, including DNA mutations and chromosomal abnormalities, are primary drivers of tumor formation and cancer progression. These alterations can endow cells with a selective growth advantage, enabling cancers to evade cell death, proliferation limits, and immune checkpoints, to metastasize throughout the body. Genetic alterations occur due to failures of the genome stability pathways. In many cancers, the rate of alteration is further accelerated by the deregulation of these processes. The deubiquitinating enzyme ubiquitin specific protease 7 (USP7) has recently emerged as a key regulator of ubiquitination in the genome stability pathways. USP7 is also deregulated in many cancer types, where deviances in USP7 protein levels are correlated with cancer progression. In this work, we review the increasingly evident role of USP7 in maintaining genome stability, the links between USP7 deregulation and cancer progression, as well as the rationale of targeting USP7 in cancer therapy.

Enhanced UV Resistance Role of Death Domain-Associated Protein in Human MDA-MB-231 Breast Cancer Cells by Regulation of G2 DNA Damage Checkpoint

Purpose:

Death domain–associated protein (DAXX) is a multifunctional nuclear protein involved in apoptosis, transcription, deoxyribonucleic acid damage response, and tumorigenesis. However, the role of DAXX in breast cancer development and progression remains elusive. In this study, we examined the expression patterns and function of DAXX in human breast cancer samples and cell lines.

Methods:

Immunohistochemistry was used to analyze the expression and localization patterns of DAXX. Additionally, we investigated whether DAXX played an intrinsic role in the cellular response to damage induced by ultraviolet (UV) irradiation in MDA-MB-231 breast cancer cells (isolated at M D Anderson from a pleural effusion of a patient with invasive ductal carcinoma).

Results:

Our results showed that nucleus size, chromatin organization, and DAXX localization were altered in breast cancer tissues compared with those in control tissues. Compared with cytoplasmic and nuclear expression in benign breast tissues, DAXX was colocalized with promyelocytic leukemia in nuclei with a granular distribution. Endogenous DAXX messenger ribonucleic acid levels were upregulated upon UV radiation in MDA-MB-231 cells. DAXX-deficient cells tended to be more sensitive to irradiation than control cells. Conversely, DAXX-overexpressing cells exhibited reduced phosphorylated histone H2AX (γ-H2AX) accumulation, increased cell survival, and resistance to UV-induced damage. The protective effects of DAXX may be related to the activation of the ataxia telangiectasia mutated (ATM)-checkpoint kinase 2 (ATM-CHK2)-cell division cycle 25c (CDC25c) signaling pathways in Gap2/Mitosis (G₂/M) checkpoint and ultimately cell cycle arrest at G₂/M phase.

Conclusions:

Taken together, these results suggested that DAXX may be an essential component in breast cancer initiation, malignant progression, and radioresistance.

Complex interactomes and post-translational modifications of the regulatory proteins HABP4 and SERBP1 suggest pleiotropic cellular functions

The 57 kDa antigen recognized by the Ki-1 antibody, is also known as intracellular hyaluronic acid binding protein 4 and shares 40.7% identity and 67.4% similarity with serpin mRNA binding protein 1, which is also named CGI-55, or plasminogen activator inhibitor type-1-RNA binding protein-1, indicating that they might be paralog proteins, possibly with similar or redundant functions in human cells. Through the identification of their protein interactomes, both regulatory proteins have been functionally implicated in transcriptional regulation, mRNA metabolism, specifically RNA splicing, the regulation of mRNA stability, especially, in the context of the progesterone hormone response, and the DNA damage response. Both proteins also show a complex pattern of post-translational modifications, involving Ser/Thr phosphorylation, mainly through protein kinase C, arginine methylation and SUMOylation, suggesting that their functions and locations are highly regulated. Furthermore, they show a highly dynamic cellular localization pattern with localizations in both the cytoplasm and nucleus as well as punctuated localizations in both granular cytoplasmic protein bodies, upon stress, and nuclear splicing speckles. Several reports in the literature show altered expressions of both regulatory proteins in a series of cancers as well as mutations in their genes that may contribute to tumorigenesis. This review highlights important aspects of the structure, interactome, post-translational modifications, sub-cellular localization and function of both regulatory proteins and further discusses their possible functions and their potential as tumor markers in different cancer settings.

DAXX, as a Tumor Suppressor, Impacts DNA Damage Repair and Sensitizes BRCA-Proficient TNBC Cells to PARP Inhibitors

Treatment options are limited for patients with triple negative breast cancer (TNBC). Understanding genes that participate in cancer progression and DNA damage response (DDR) may improve therapeutic strategies for TNBC. DAXX, a death domain-associated protein, has been reported to be critically involved in cancer progression and drug sensitivity in multiple cancer types. However, its role in breast cancer, especially for TNBC, remains unclear. Here, we demonstrated a tumor suppressor function of DAXX in TNBC proliferation, colony formation, and migration. In Mouse Xenograft Models, DAXX remarkably inhibited tumorigenicity of TNBC cells. Mechanistically, DAXX could directly bind to the promoter region of RAD51 and impede DNA damage repair, which impacted the protection mechanism of tumor cells that much depended on remaining DDR pathways for cell growth. Furthermore, DAXX-mediated inefficient DNA damage repair could sensitize BRCA-proficient TNBC cells to PARP inhibitors. Additionally, we identified that dual RAD51 and PARP inhibition with RI-1 and ABT888 significantly reduced TNBC growth both in vitro and in vivo, which provided the first evidence of combining RAD51 and PARP inhibition in BRCA-proficient TNBC. In conclusion, our data support DAXX as a modulator of DNA damage repair and suppressor of TNBC progression to sensitize tumors to the PARP inhibitor by repressing RAD51 functions. These provide an effective strategy for a better application of PARP inhibition in the treatment of TNBC.

The Clinical Implications of Death Domain-Associated Protein (DAXX) Expression

Background

Death domain-associated protein (DAXX), originally identified as a pro-apoptotic protein, is now understood to be either a pro-apoptotic or an anti-apoptotic factor with a chromatin remodeler, depending on the cell type and context. This study evaluated DAXX expression and its clinical implications in squamous cell carcinoma of the esophagus.

Methods

Paraffin-embedded tissues from 60 cases of esophageal squamous carcinoma were analyzed immunohistochemically. An immune reaction with more than 10% of tumor cells was interpreted as positive. Positive reactions were sorted into 2 groups: reactions in 11%–50% of tumor cells and reactions in more than 51% of tumor cells, and the correlations between expression and survival and clinical prognosticators were analyzed.

Results

Forty-three of the 60 cases (71.7%) showed strong nuclear DAXX expression, among which 19 cases showed a positive reaction (31.7%) in 11%–50% of tumor cells, and 24 cases (40.0%) showed a positive reaction in more than 51% of tumor cells. A negative reaction was found in 17 cases (28.3%). These patterns of immunostaining were significantly associated with the N stage (p=0.005) and American Joint Committee on Cancer stage (p=0.001), but overall survival showed no significant difference. There were no correlations of DAXX expression with age, gender, or T stage. However, in stage IIB (p=0.046) and stage IV (p=0.014) disease, DAXX expression was significantly correlated with survival.

Conclusion

This investigation found upregulation of DAXX in esophageal cancer, with a 71.7% expression rate. DAXX immunostaining could be used in clinical practice to predict aggressive tumors with lymph node metastasis in advanced-stage disease, especially in stages IIB and IV.

Emerging role of mutations in epigenetic regulators including MLL2 derived from The Cancer Genome Atlas for cervical cancer

BACKGROUND

Cervical cancer is the second most common cause of cancer deaths in women worldwide. The aim of this study is to exploit novel pathogenic genes in cervical carcinogenesis.

METHOD

The somatic mutations from 194 patients with cervical cancer were obtained from the Cancer Genome Atlas (TCGA) publically accessible exome-sequencing database. We investigated mutated gene enrichment in the 12 cancer core pathways and predicted possible post-translational modifications. Additionally, we predicted the impact of mutations by scores quantifying the deleterious effects of the mutations. We also examined the immunogenicity of the mutations based on the mutant peptides' strong binding with major histocompatibility complex class I molecules (MHC-I). The Kaplan-Meier method was used for the survival analysis.

RESULTS

We observed that the chromatin modification pathway was significantly mutated across all clinical stages. Among the mutated genes involved in this pathway, we observed that the histone modification regulators were primarily mutated. Interestingly, of the 197 mutations in the 26 epigenetic regulators in this pathway, 25 missense mutations in 13 genes were predicted in or around the phosphorylation sites. Only mutations in the histone methyltransferase MLL2 exhibited poor survival. Compared to other mutations in MLL2 mutant patients, we noticed that the mutational scores prioritized mutations in MLL2, which indicates that it is more likely to have deleterious effects to the human genome. Around half of all of the mutations were found to bind strongly to MHC-I, suggesting that patients are likely to benefit from immunotherapy.

CONCLUSIONS

Our results highlight the emerging role of mutations in epigenetic regulators, particularly MLL2, in cervical carcinogenesis, which suggests a potential disruption of histone modifications. These data have implications for further investigation of the mechanism of epigenetic dysregulation and for treatment of cervical cancer.

Regulation of the Mdm2-p53 signaling axis in the DNA damage response and tumorigenesis

The p53 tumor suppressor acts as a guardian of the genome in mammalian cells undergoing DNA double strand breaks induced by a various forms of cell stress, including inappropriate growth signals or ionizing radiation. Following damage, p53 protein levels become greatly elevated in cells and p53 functions primarily as a transcription factor to regulate the expression a wide variety of genes that coordinate this DNA damage response. In cells undergoing high amounts of DNA damage, p53 can promote apoptosis, whereas in cells undergoing less damage, p53 promotes senescence or transient cell growth arrest and the expression of genes involved in DNA repair, depending upon the cell type and level of damage. Failure of the damaged cell to undergo growth arrest or apoptosis, or to respond to the DNA damage by other p53-coordinated mechanisms, can lead to inappropriate cell growth and tumorigenesis. In cells that have successfully responded to genetic damage, the amount of p53 present in the cell must return to basal levels in order for the cell to resume normal growth and function. Although regulation of p53 levels and function is coordinated by many proteins, it is now widely accepted that the master regulator of p53 is Mdm2. In this review, we discuss the role(s) of p53 in the DNA damage response and in tumor suppression, and how post-translational modification of Mdm2 regulates the Mdm2-p53 signaling axis to govern p53 activities in the cell.

Towards an understanding of regulating Cajal body activity by protein modification

The biogenesis of small nuclear ribonucleoproteins (snRNPs), small Cajal body-specific RNPs (scaRNPs), small nucleolar RNPs (snoRNPs) and the telomerase RNP involves Cajal bodies (CBs). Although many components enriched in the CB contain post-translational modifications (PTMs), little is known about how these modifications impact individual protein function within the CB and, in concert with other modified factors, collectively regulate CB activity. Since all components of the CB also reside in other cellular locations, it is also important that we understand how PTMs affect the subcellular localization of CB components. In this review, we explore the current knowledge of PTMs on the activity of proteins known to enrich in CBs in an effort to highlight current progress as well as illuminate paths for future investigation.

Age-dependent differential expression of death-associated protein 6 (Daxx) in various peripheral tissues and different brain regions of C57BL/6 male mice

Death-associated protein 6 (DAXX) is a ubiquitous protein implicated in various cellular processes such as apoptosis, tumorigenesis, development and transcription. The role of DAXX is however ambiguous and many contradictory results regarding its function in apoptosis upon various cellular stresses are described in the literature. In order to have a better understanding of the role of DAXX throughout the entire organism under physiological stress conditions, we have characterized the mRNA levels, protein expression and the proteolytic processing of DAXX in the normal aging process in peripheral organs and brain regions in C57BL/6 male mice. Overall, Daxx mRNA expression decreases with aging in the liver, kidney, heart, cortex and cerebellum. In contrast, an increase is observed in the striatum. The protein expression of DAXX and of its proteolytic fragments increases with aging in the kidney, heart and cortex. In liver and spleen, no changes are observed while in the striatum and cerebellum, certain forms increase and others decrease with age, suggesting that the functions of DAXX may be cell type dependent. This study provides important details regarding the expression and post-translational modifications of DAXX in aging in the entire organism and provides reference data for the deregulation observed in age-associated diseases.

Cellular response to alkylating agent MNNG is impaired in STAT1-deficients cells

The SN 1 alkylating agents activate the mismatch repair system leading to delayed G2 /M cell cycle arrest and DNA repair with subsequent survival or cell death. STAT1, an anti-proliferative and pro-apoptotic transcription factor is known to potentiate p53 and to affect DNA-damage cellular response. We studied whether STAT1 may modulate cell fate following activation of the mismatch repair system upon exposure to the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Using STAT1-proficient or -deficient cell lines, we found that STAT1 is required for: (i) reduction in the extent of DNA lesions, (ii) rapid phosphorylation of T68-CHK2 and of S15-p53, (iii) progression through the G2 /M checkpoint and (iv) long-term survival following treatment with MNNG. Presence of STAT1 is critical for the formation of a p53-DNA complex comprising: STAT1, c-Abl and MLH1 following exposure to MNNG. Importantly, presence of STAT1 allows recruitment of c-Abl to p53-DNA complex and links c-Abl tyrosine kinase activity to MNNG-toxicity. Thus, our data highlight the important modulatory role of STAT1 in the signalling pathway activated by the mismatch repair system. This ability of STAT1 to favour resistance to MNNG indicates the targeting of STAT1 pathway as a therapeutic option for enhancing the efficacy of SN1 alkylating agent-based chemotherapy.

8-60hIPP5(m)-induced G2/M cell cycle arrest involves activation of ATM/p53/p21(cip1/waf1) pathways and delayed cyclin B1 nuclear translocation

Protein phosphatase 1 (PP1) is a major serine/threonine phosphatase that controls gene expression and cell cycle progression. The active mutant IPP5 (8-60hIPP5(m)), the latest member of the inhibitory molecules for PP1, has been shown to inhibit the growth of human cervix carcinoma cells (HeLa). In order to elucidate the underlying mechanisms, the present study assessed overexpression of 8-60hIPP5(m) in HeLa cells. Flow cytometric and biochemical analyses showed that overexpression of 8-60hIPP5(m) induced G2/M-phase arrest, which was accompanied by the upregulation of cyclin B1 and phosphorylation of G2/M-phase proteins ATM, p53, p21(cip1/waf1) and Cdc2, suggesting that 8-60hIPP5(m) induces G2/M arrest through activation of the ATM/p53/p21(cip1/waf1)/Cdc2/ cyclin B1 pathways. We further showed that overexpression of 8-60hIPP5(m) led to delayed nuclear translocation of cyclin B1. 8-60hIPP5(m) also could translocate to the nucleus in G2/M phase and interact with pp1α and Cdc2 as demonstrated by co-precipitation assay. Taken together, our data demonstrate a novel role for 8-60hIPP5(m) in regulation of cell cycle in HeLa cells, possibly contributing to the development of new therapeutic strategies for cervix carcinoma.

DNA damage-induced regulatory interplay between DAXX, p53, ATM kinase and Wip1 phosphatase

Death domain-associated protein 6 (DAXX) is a histone chaperone, putative regulator of apoptosis and transcription, and candidate modulator of p53-mediated gene expression following DNA damage. DAXX becomes phosphorylated upon DNA damage, however regulation of this modification, and its relationship to p53 remain unclear. Here we show that in human cells exposed to ionizing radiation or genotoxic drugs etoposide and neocarzinostatin, DAXX became rapidly phosphorylated in an ATM kinase-dependent manner. Our deletion and site-directed mutagenesis experiments identified Serine 564 (S564) as the dominant ATM-targeted site of DAXX, and immunofluorescence experiments revealed localization of S564-phosphorylated DAXX to PML nuclear bodies. Furthermore, using a panel of human cell types, we identified the p53-regulated Wip1 protein phosphatase as a key negative regulator of DAXX phosphorylation at S564, both in vitro and in cells. Consistent with the emerging oncogenic role of Wip1, its DAXX-dephosphorylating impact was most apparent in cancer cell lines harboring gain-of-function mutant and/or overexpressed Wip1. Unexpectedly, while Wip1 depletion increased DAXX phosphorylation both before and after DNA damage and increased p53 stability and transcriptional activity, knock-down of DAXX impacted neither p53 stabilization nor p53-mediated expression of Gadd45a, Noxa, Mdm2, p21, Puma, Sesn2, Tigar or Wip1. Consistently, analyses of cells with genetic, TALEN-mediated DAXX deletion corroborated the notion that neither phosphorylated nor non-phosphorylated DAXX is required for p53-mediated gene expression upon DNA damage. Overall, we identify ATM kinase and Wip1 phosphatase as opposing regulators of DAXX-S564 phosphorylation, and propose that the role of DAXX phosphorylation and DAXX itself are independent of p53-mediated gene expression.

Regulation of MDM2 Stability After DNA Damage

Cells in our body are constantly exposed to various stresses and threats to their genomic integrity. The tumor suppressor protein p53 plays a critical role in successful defense against these threats by inducing apoptotic cell death or cell cycle arrest. In unstressed conditions, p53 levels and activity must be kept low to prevent lethal activation of apoptotic and senescence pathways. However, upon DNA damage or other stressors, p53 is released from its inhibitory state to induce an array of apoptosis and cell cycle genes. Conversely, inactivation of p53 could promote unrestrained tumor proliferation and failure to appropriately undergo apoptotic cell death, which could, in turn, lead to carcinogenesis. The ubiquitin E3 ligase MDM2 is the most critical inhibitor of p53 that determines the cellular response to various p53-activating agents, including DNA damage. MDM2 activity is controlled by post-translational modifications, especially phosphorylation. However, accumulating evidence suggests that MDM2 is also regulated at the level of protein stability, which is controlled by the ubiquitin-proteasome pathway. Here, we discuss how MDM2 can be regulated in response to DNA damage with particular focus on the regulation of MDM2 protein stability.

Multifunctional role of ATM/Tel1 kinase in genome stability: from the DNA damage response to telomere maintenance

The mammalian protein kinase ataxia telangiectasia mutated (ATM) is a key regulator of the DNA double-strand-break response and belongs to the evolutionary conserved phosphatidylinositol-3-kinase-related protein kinases. ATM deficiency causes ataxia telangiectasia (AT), a genetic disorder that is characterized by premature aging, cerebellar neuropathy, immunodeficiency, and predisposition to cancer. AT cells show defects in the DNA damage-response pathway, cell-cycle control, and telomere maintenance and length regulation. Likewise, in Saccharomyces cerevisiae, haploid strains defective in the TEL1 gene, the ATM ortholog, show chromosomal aberrations and short telomeres. In this review, we outline the complex role of ATM/Tel1 in maintaining genomic stability through its control of numerous aspects of cellular survival. In particular, we describe how ATM/Tel1 participates in the signal transduction pathways elicited by DNA damage and in telomere homeostasis and its importance as a barrier to cancer development.

Pathway landscapes and epigenetic regulation in breast cancer and melanoma cell lines

BACKGROUND

Epigenetic variation is a main regulation mechanism of gene expression in various cancer histotypes, and due to its reversibility, the potential impact in therapy can be very relevant.

METHODS

Based on a selected pair, breast cancer (BC) and melanoma, we conducted inference analysis in parallel on a few cell lines (MCF-7 for BC and A375 for melanoma). Starting from differential expression after treatment with a demethylating agent, the 5-Aza-2'-deoxycytidine (DAC), we provided pathway enrichment analysis and gene regulatory maps with cross-linked microRNAs and transcription factors.

RESULTS

Several oncogenic signaling pathways altered upon DAC treatment were detected with significant enrichment. We represented the association between these cancers by depicting the landscape of common and specific variation affecting them.

Immunohistochemical analysis of chromatin remodeler DAXX in high grade urothelial carcinoma

Background/Aims

The chromatin remodeler DAXX, a predominantly nuclear protein, regulates the status of chromatin organization. The aim of this exploratory immunohistochemical study was to evaluate DAXX protein expression in high grade invasive urothelial carcinoma (UC) of the bladder as a biological regulator of aggressiveness.

Methods

Quantitative analysis was made on DAXX immunostained nuclei in tissue sections from 5 cases of bladder normal urothelium (NU) and 5 cases of bladder pT1 UC. Carcinoma in situ (CIS) and high grade papillary carcinoma (HGPCa) were identified in 2 out of 5 UC cases.

Results

The nuclei in UC show an open configuration of the chromatin composed of granules varying in size and distribution and a mean nuclear area 1.7 times greater than that in NU (UC: mean and SD 24.4 ± 11.4 square microns; NU: 14.8 6.5 square microns. The differences are statistically significant). 70% of the NU nuclei are immunostained, whereas 90% of UC nuclei are positive. The mean gray level value in UC, related to the intensity of nuclear immunostaining, is lower than in NU by a factor of 0.94 (UC: mean and SD 100 ± 15; NU: 106 ± 15. The differences are statistically significant). In particular, the value in the nuclei adjacent to the stroma in UC is slightly lower than in the intermediate cell layers by factor of 0.98, whereas in NU it is slightly greater by a factor 1.02 and 1.04 compared to the intermediate and superficial cell layers. The values in CIS and HGPCa are similar to those in UC.

Conclusions

The quantitative immunohistochemical analysis shows an altered protein expression of chromatin remodeler DAXX in UC and in its preinvasive phases, when compared to NU. DAXX evaluation, if associated with markers related to global DNA methylation and histone acetylation, could be used in clinical practice as a marker of aggressiveness.

Virtual slides

The virtual slides for this article can be found here:

http://www.diagnosticpathology.diagnomx.eu/vs/1398457297102379