Cerebral Ischemic Reperfusion Injury Following Recanalization of Large Vessel Occlusions

Although stroke has recently dropped to become the nation's fifth leading cause of mortality, it remains the top leading cause of morbidity and disability in the US. Recent advances in stroke treatment, including intravenous fibrinolysis and mechanical thromboembolectomy, allow treatment of a greater proportion of stroke patients than ever before. While intra-arterial fibrinolysis with recombinant tissue plasminogen is an effective for treatment of a broad range of acute ischemic strokes, endovascular mechanical thromboembolectomy procedures treat severe strokes due to large artery occlusions, often resistant to intravenous drug. Together, these procedures result in a greater proportion of revascularized stroke patients than ever before, up to 88% in 1 recent trial (EXTEND-IA). Subsequently, there is a growing need for neurointensivists to develop more effective strategies to manage stroke patients following successful reperfusion. Cerebral ischemic reperfusion injury (CIRI) is defined as deterioration of brain tissue suffered from ischemia that concomitantly reverses the benefits of re-establishing cerebral blood flow following mechanical or chemical therapies for acute ischemic stroke. Herein, we examine the pathophysiology of CIRI, imaging modalities, and potential neuroprotective strategies. Additionally, we sought to lay down a potential treatment approach for patients with CIRI following emergent endovascular recanalization for acute ischemic stroke.

Renal tubular epithelial cell-derived BAFF expression mediates kidney damage and correlates with activity of proliferative lupus nephritis in mouse and men

B-cell activating factor of the tumour necrosis factor family (BAFF) is a cytokine, mainly produced by hematopoietic cells (e.g. monocytes/macrophages, dendritic cells), indispensable for B-cell maturation. The BLISS studies have demonstrated that blocking BAFF by the human monoclonal antibody belimumab is a valuable therapeutic approach in patients with clinically and serologically active systemic lupus erythematosus (SLE). However, the defined sources of BAFF, which contributes to SLE, are still unclear. Recent findings show that BAFF expression is not restricted to myeloid cells. Since lupus nephritis is the main cause of morbidity and mortality for SLE patients, the aim of this study was to investigate whether renal tubular epithelial cells (TEC) are an important source of BAFF and thus may contribute to the pathogenesis and progression of SLE. We found BAFF expression both in cultured murine and human TEC. These results could be verified with in situ data from the kidney. Moreover, BAFF expression in the kidneys of lupus-prone MRL- Fas^lpr mice correlated with disease activity, and BAFF expression on TEC in biopsies of patients with diffuse proliferative lupus nephritis showed a correlation with the histopathological activity index. In vitro functional assays revealed an autocrine loop of BAFF with its binding receptors on TEC, resulting in a strong induction of colony stimulating factor-1. Finally, we identified divergent effects of BAFF on TEC depending on the surrounding milieu ('inflammatory versus non-inflammatory'). Taken together, our findings indicate that renal-derived BAFF may play an important role in the pathophysiology of the systemic autoimmune disease SLE.

Immaturity for gestational age of microvasculature and placental barrier in term placentas with high weight

OBJECTIVE

Villous immaturity for gestational age is a multifactorial developmental deviation associated with unexpected placental insufficiency, fetal hypoxia and term fetal death. In our previous work we have shown that immature CD15+/CD31+/CD34+ endothelial cells were an important indicator of placental villous immaturity and chronic insufficiency. The aim of this study was to perform a comparative analysis of CD15-marked immaturity in the vessel walls between normal and pathological term placentas of clinically and structurally heterogenous groups with normal, low and high weight.

STUDY DESIGN

165 clinically normal and pathological placentas of gestational age 39-42 with normal weight (25-75 percentile), low weight (<10 percentile) and high weight (>90 percentile) were structurally and immunohistochemically analyzed. Excluded were placentas with a severe form of placental insufficiency associated with intrauterine fetal death, low APGAR-score, genetic and chromosomal diseases or placental inflammations. The distribution patterns of CD15, CD31 and CD34 were assessed separately in the macrovasculature, microvasculature and placental barrier (PB) - associated capillaries.

RESULTS

All placental groups with normal weight, low weight and high weight include normal, accelerated villous maturation or villous immaturity independent of their weight. However, a significant increase of immature CD15+/CD31+/CD34+ endothelial cells was detected in microvasculature and PB -associated capillaries in high weight-placentas (63.5%/52.2%), compared to those of normal weight (13.8%/8.2%) and low weight (16.1%/17.8%). The distribution of macrovascular immature CD15+/CD31+/CD34+ endothelial cells did not show such marked differences.

CONCLUSION

We have identified the immaturity of microvasculature and PB -associated capillaries with a pathological persistency of immature CD15+/CD31+/CD34+ endothelial cells and a reduction of terminally differentiated CD15-/CD31+/CD34+ endothelial cells in a structurally and clinically heterogeneous group of high weight-placentas. We assume that immaturity of placental vessels are part of prenatal adaptational processes that can be recruited in different emergency situations and may provide potential targets of therapeutic correction of placental growth and chronic insufficiency. We therefore recommend the use of CD15-based immunophenotyping as a method to identify latent unfavorable conditions of fetal development in the intrauterine life and individual risk of disease in the postnatal period.

[Multiparametric MRI and MRI-TRUS fusion biopsy in patients with prior negative prostate biopsy]

BACKGROUND

Multiparametric MRI (mpMRI) plays an increasingly important role in prostate cancer (PCa) diagnostics and is recommended in men with previously negative TRUS biopsy. The optimal biopsy method after mpMRI is under discussion.

OBJECTIVE

Prospective, PIRADS- and START-conform analysis of the relevance of mpMRI and MRI-TRUS fusion biopsy in patients with prior negative TRUS biopsy and comparison of the detection rates of fusion-targeted biopsies (tB) and systematic transperineal saturation biopsies (sB).

MATERIALS AND METHODS

Between 10/2012 and 09/2015, 287 patients with prior negative TRUS biopsy underwent mpMRI and software-assisted, rigid MRI-TRUS fusion biopsy. In addition to and strictly separated from sB (median cores n = 24), tB (median cores per patient n = 4, per lesion n = 3) were performed in case of suspicious MRI lesions (PIRADS ≥ 2). Both biopsy methods were compared by using McNemar's test.

RESULTS

Of the 287 patients, 148 (52 %) had positive biopsies. Of these, 108/287 (38 %) had significant PCa (Gleason Score [GS] = 3 + 3 and PSA ≥ 10 ng/ml or GS ≥ 3 + 4) and again 43/287 (15 %) had a GS ≥ 4 + 3 PCa. sB failed to diagnose 8/148 PCa (5.4 %) and 6/108 significant PCa (5.5 %), whereas tB failed to diagnose 48 (32.4 %) PCa (p < 0.0001) and 22 (20.4 %) significant PCa (p = 0.0046). Of the PCa missed by tB, 11  had a GS ≥ 3 + 4 and 5 of these a GS = 4 + 3. On a per patient basis, MRI failed to detect 5 significant PCa, whereby 17 of the significant PCa were missed by fusion-targeted cores alone.

CONCLUSIONS

In men with unsuspicious MRI (PIRADS < 3), there is a 11 % risk of significant PCa. In case of suspicious MRI lesions, the combination of both biopsy approaches offers maximum tumor detection.

Anchoring Pipeline Flow Diverter Construct in the Treatment of Traumatic Distal Cervical Carotid Artery Injury

Background

Traumatic extracranial internal carotid artery (ICA) dissections are uncommon and can be difficult to treat. Thinning of adventitia and dilatation may occur following arterial dissection, thus resulting in a fusiform pseudoaneurysm, which can subsequently cause bleeding, expanding, or pulsatile hematoma. Currently, medical management with anticoagulation remains the first line of treatment and yields good outcomes in 75% of cases with a mortality rate of 3-4%. Endovascular intervention is indicated with failure of medical therapy, progressive enlargement of a traumatic pseudoaneurysm, acute flow-related infarcts due to vessel occlusion, or when anticoagulation is contraindicated due to risk of pseudoaneurysm rupture and hemorrhage. Recognized interventional treatments include parent artery occlusion with or without revascularization, endovascular coil embolization, and covered stenting.

Summary

A wide variety of endovascular stents are available that are capable of opening a stenosed vessel while obliterating the associated false lumen and providing a scaffold for embolization of the pseudoaneurysm. The use of the Pipeline Embolization Device (PED) in the management of traumatic intracranial pseudoaneurysms has been described. However, there are few reports on the usage of the PED for treating traumatic extracranial ICA dissection and/or pseudoaneurysms. However, a potential complication of the use of PED in the extracranial ICA is a hypothetical tendency to migrate in a mobile vessel. Thus, the risk of migration of the PED has encouraged practitioners to adopt strategies to limit this risk.

Key Messages

We describe different techniques employed to anchor the flow-diverting construct within tortuous, mobile vessels.

Histopathological Differences Between the Anterior and Posterior Brain Arteries as a Function of Aging

BACKGROUND AND PURPOSE

We tested the hypothesis that posterior brain arteries differ pathologically from anterior brain arteries and that this difference varies with age.

METHODS

Brain large arteries from 194 autopsied individuals (mean age 56±17 years, 63% men, 25% nonwhite, 17% with brain infarcts) were analyzed to obtain the areas of arterial layers and lumen as well as the relative content of elastin, collagen, and amyloid. Visual rating was used to determine the prevalence of atheroma, calcification, vasa vasorum, pattern of intima thickening, and internal elastic lamina gaps. We used multilevel models adjusting for age, sex, ethnicity, vascular risk factors, artery type and location, and multiple comparisons.

RESULTS

Of 1362 large artery segments, 5% had vasa vasorum, 5% had calcifications, 15% had concentric intimal thickening, and 11% had atheromas. Posterior brain arteries had thinner walls, less elastin, and more concentric intima thickening than anterior brain arteries. Compared to anterior brain arteries, the basilar artery had higher arterial area encircled by the internal elastic lamina, whereas the vertebral arteries had higher prevalence of elastin loss, concentric intima thickening, and nonatherosclerotic stenosis. In younger individuals, vertebral artery calcifications were more likely than calcification in anterior brain arteries, but this difference attenuated with age.

CONCLUSIONS

Posterior brain arteries differ pathologically from anterior brain arteries in the degree of wall thickening, elastin loss, and concentric intimal thickening.

[Cell death in malignant tumors. Relevance of cell death regulation for metastasis]

Defects in the regulation of cell death are important causes for both the development and therapy resistance of malignant tumors. Several distinct, molecularly defined types of cell death are known, such as apoptosis, anoikis, and necroptosis. Moreover, the specific triggering of cell death plays an important role in the prevention of metastasis. The results of recent studies have shown that various types of cell death are pivotal at different steps of the metastasis cascade, in order to prevent cellular detachment, migration, invasion, intravasation, extravasation and the establishment of micrometastasis and macrometastasis. At the subcellular level, numerous links exist between cell death regulation and metastasis, specifically regarding signaling pathways and individual proteins with dual or multiple functions. As an example, the decoy receptor 3 protein (DcR3) functions both as an anti-apoptotic protein and as a direct promotor of invasion and migration of tumor cells. In summary, the specific triggering of cell death plays a pivotal role for the prevention of metastasis. On the other hand, the stepwise process of metastasis represents a mechanism of selection resulting in established metastases with a multiresistant phenotype which corresponds to the clinical observation that many metastasized cancers are therapy resistant. In the future, innovative diagnostic tests to individually predict the resistance pattern and possibilities to overcome resistance are urgently needed.

Use of Intra-aortic- Balloon Pump Counterpulsation in Patients with Symptomatic Vasospasm Following Subarachnoid Hemorrhage and Neurogenic Stress Cardiomyopathy

INTRODUCTION

Intra-aortic counterpulsation balloon pumps (IABPs) have been widely used to augment hemodynamics in critically ill patients with cardiogenic shock and have recently been proposed as a management strategy for subarachnoid hemorrhage (SAH) patients with neurogenic stress cardiomyopathy (NSC). Prior case series have described the use of IABP as a means to manage cardiogenic shock in this patient population; however, we sought to describe our experience with IABP as a means to wean vasopressor requirement while augmenting hemodynamics and maintaining pressures at goal.

METHODS

Five patients were identified from a single center, prospective, observational cohort study that received an IABP for the management of ischemia related to cerebral vasospasm in the setting of NSC. We evaluated all cases for efficacy of IABP in reducing vasopressor requirement, and complications.

RESULTS

Vasopressor requirements were reduced by a mean of 50% (range 25-65%) following IABPs placement within 24-48 h. There were no significant complications from IABPs. Out of the five patients, the outcome in three cases was favorable (mRS≤1). Two patients suffered delayed cerebral ischemia (DCI), one patient passed away due to severe sepsis, and one patient was left with severe disability. Only one patient required anticoagulation and that was for a preexisting deep venous thrombosis.

CONCLUSION

The use of IABPs may be beneficial as an adjunctive therapy in SAH patients with concomitant symptomatic vasospasm and NSC.

[Intratumoral heterogeneity in renal cell carcinoma. Molecular basis and translational implications]

Advanced clear cell renal cell carcinoma is characterized by extensive intratumoral genomic heterogeneity and branched as well as convergent evolutionary traits with genomically different subclones evolving in parallel in the same tumor. Distinct driver mutations can be found in spatially separated subclones, which may hinder the development of novel targeted therapies. However, truncal mutations of the VHL tumor suppressor gene and chromosome 3p loss were ubiquitously detected and will hence continue to be a focus of future drug development. Nevertheless, genomic instability, enhanced tumor genome plasticity and intratumoral heterogeneity are likely to represent major challenges towards biomarker development and personalized patient care.

The embryo-placental CD15-positive "vasculogenic zones" as a source of propranolol-sensitive pediatric vascular tumors

OBJECTIVE

Propranolol-induced involution is a unique biological feature of some pediatric vascular tumors, for instance infantile hemangioma (IH), cerebral cavernoma or chorioangioma. Currently, the cellular origin of these distinct tumors is unclear. In this study, we tested the hypothesis that propranolol-responsive vascular tumors are derived from common vessel-forming CD15 + progenitor cells which occur in early gestation. The aim of this study was to identify the tumor-relevant CD15 + progenitors at the early stages of embryo-placental development.

MATERIALS AND METHODS

Human embryo-placental units of 4-8 weeks gestation and pediatric vascular tumors were tested for expression of the tumor-relevant markers CD15, CD31 and CD34.

RESULTS

Placental vessel-forming progenitors were characterized by immunostaining for CD15, CD31, and CD34. In embryonic tissue, a discontinuous CD15+/CD31+/CD34 + progenitors was detected in immature vessels of the skin, neural tube, spinal and cerebral meninges. Similarly, vessels in IH and chorioangioma exhibited a co-expression of CD15, CD31, and CD34. In contrast, the majority of embryonic vessels presented a CD31+/CD34+, but CD15-negative immunophenotypic pattern.

DISCUSSION

Our results suggest the existence of a CD15+ "vasculogenic zones" in the embryo-placental unit as well as in IH and chorioangioma. A site-specific correlation between normal embryo-placental and tumoral vessel-forming CD15 + progenitors was demonstrated.

CONCLUSION

Hence, site- and stage-specific CD15 + progenitors of vascular wall could be considered as propronalol-sensitive targets and source of pre- and postnatal vascular tumors. We propose, that the CD15+ "vasculogenic zones" are a site-specific reserve of multi-lineage progenitors that could be recruited in pre- and postnatal emergency situations.

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. They are found in a number of biological fluids and are known to carry a variety of proteins, lipids, and nucleic acid molecules. Originally thought to be little more than reservoirs for cellular debris, the roles of exosomes regulating biological processes and in diseases are increasingly appreciated. Several methods have been described for isolating exosomes from cellular culture media and biological fluids. Due to their small size and low density, differential ultracentrifugation and/or ultrafiltration are the most commonly used techniques for exosome isolation. However, plasma of HIV-1 infected individuals contains both exosomes and HIV viral particles, which are similar in size and density. Thus, efficient separation of exosomes from HIV viral particles in human plasma has been a challenge. To address this limitation, we developed a procedure modified from Cantin et. al., 2008 for purification of exosomes from HIV particles in human plasma. Iodixanol velocity gradients were used to separate exosomes from HIV-1 particles in the plasma of HIV-1 positive individuals. Virus particles were identified by p24 ELISA. Exosomes were identified on the basis of exosome markers acetylcholinesterase (AChE), and the CD9, CD63, and CD45 antigens. Our gradient procedure yielded exosome preparations free of virus particles. The efficient purification of exosomes from human plasma enabled us to examine the content of plasma-derived exosomes and to investigate their immune modulatory potential and other biological functions.

Cooperation of BRAF(F595L) and mutant HRAS in histiocytic sarcoma provides new insights into oncogenic BRAF signaling

Activating BRAF mutations, in particular V600E/K, drive many cancers and are considered mutually exclusive with mutant RAS, whereas inactivating BRAF mutations in the D(594)F(595)G(596) motif cooperate with RAS via paradoxical MEK/ERK activation. Due to the increasing use of comprehensive tumor genomic profiling, many non-V600 BRAF mutations are being detected whose functional consequences and therapeutic actionability are often unknown. We investigated an atypical BRAF mutation, F595L, which was identified along with mutant HRAS in histiocytic sarcoma and also occurs in epithelial cancers, melanoma and neuroblastoma, and determined its interaction with mutant RAS. Unlike other DFG motif mutants, BRAF(F595L) is a gain-of-function variant with intermediate activity that does not act paradoxically, but nevertheless cooperates with mutant RAS to promote oncogenic signaling, which is efficiently blocked by pan-RAF and MEK inhibitors. Mutation data from patients and cell lines show that BRAF(F595L), as well as other intermediate-activity BRAF mutations, frequently coincide with mutant RAS in various cancers. These data define a distinct class of activating BRAF mutations, extend the spectrum of patients with systemic histiocytoses and other malignancies who are candidates for therapeutic blockade of the RAF-MEK-ERK pathway and underscore the value of comprehensive genomic testing for uncovering the vulnerabilities of individual tumors.

Inhibition of Notch1 signaling overcomes resistance to the death ligand Trail by specificity protein 1-dependent upregulation of death receptor 5

The Notch1 signaling pathway contributes to tumorigenesis by influencing differentiation, proliferation and apoptosis. Here, we demonstrate that inhibition of the Notch1 signaling pathway sensitizes glioblastoma cell lines and glioblastoma initiating cells to apoptosis induced by the death ligand TRAIL. This sensitization occurs through transcriptional upregulation of the death receptor 5 (DR5, TRAIL-R2). The increase in DR5 expression is abrogated by concomitant repression of the transcription factor Sp1, which directly binds to the DR5 promoter in the absence of Notch1 as revealed by chromatin immunoprecipitation. Consistent with these findings, Notch1 inhibition resulted in increased DR5 promoter activity, which was impaired by mutation of one out of two Sp1-binding sites within the proximal DR5 promoter. Moreover, we demonstrate that JNK signaling contributes to the regulation of DR5 expression by Notch1. Taken together, our results identify Notch1 as key driver for TRAIL resistance and suggest Notch1 as a promising target for anti-glioblastoma therapy.

Chemie an starren Grenzflächen, 8. [1] Kinetik der Heterogenumsetzung kovalent über Spacer an Aerosil gebundener Aminogruppen (Aminoaerosil) mit homogen gelösten Isothiocyanaten / Chemistry on Rigid Interfaces, 8 . [1] Kinetics of Suspensions of Aminoaerosil (Aerosil Covalently Linked with 3-Aminopropylgroups) with Isothiocyanates in Homogeneous Solution

In aminoaerosil, the products of the reaction of γ-aminopropyltriethoxysilane with aerosil. an intraparticular interaction of the basic amino groups with the acidic silanol groups is observed. This behaviour was established a) by adsorption experiments using n-butylamine on aerosil. resp. aminoaerosil of different support density, and b) by microcalorimetric determination of the adsorption energy of acetonitrile using aerosil and aminoaerosils of different support density as substrates.

Aminoaerosils react with isothiocyanates according to (I) with formation of covalently linked thiourea groups. Fig. 3 and Fig. 5 (with trimethylamino) show the time-turnover curves of aminoaerosils of different support density with phenylisothiocyanate. The influence of the tem­perature on the thiourea formation is demonstrated in Table III. Depending on the polarity and the size of the ligands R. the isothiocyanates react with different reaction rates with aminoaerosil (Fig. 6). Aminoaerosils with different coverage density, but with an equal molarity of amino groups and varying specific surfaces, react non-uniformly with phenylisothiocyanate (Table IV).

The comparison of the reaction of phenylisothiocyanates a) with heterogeneously by suspended aminoaerosil and b) with n-butylamine in homogeneous solution, both with equal molar amounts of NH2, shows characteristic differences (Fig. 8).

The amount of the covalently linked NH2-groups in aminoaerosils can be determined using Sanger’s reagent.

Peptide-based identification of functional motifs and their binding partners

Specific short peptides derived from motifs found in full-length proteins, in our case HIV-1 Nef, not only retain their biological function, but can also competitively inhibit the function of the full-length protein. A set of 20 Nef scanning peptides, 20 amino acids in length with each overlapping 10 amino acids of its neighbor, were used to identify motifs in Nef responsible for its induction of apoptosis. Peptides containing these apoptotic motifs induced apoptosis at levels comparable to the full-length Nef protein. A second peptide, derived from the Secretion Modification Region (SMR) of Nef, retained the ability to interact with cellular proteins involved in Nef's secretion in exosomes (exNef). This SMRwt peptide was used as the "bait" protein in co-immunoprecipitation experiments to isolate cellular proteins that bind specifically to Nef's SMR motif. Protein transfection and antibody inhibition was used to physically disrupt the interaction between Nef and mortalin, one of the isolated SMR-binding proteins, and the effect was measured with a fluorescent-based exNef secretion assay. The SMRwt peptide's ability to outcompete full-length Nef for cellular proteins that bind the SMR motif, make it the first inhibitor of exNef secretion. Thus, by employing the techniques described here, which utilize the unique properties of specific short peptides derived from motifs found in full-length proteins, one may accelerate the identification of functional motifs in proteins and the development of peptide-based inhibitors of pathogenic functions.

Preoperative therapy of esophagogastric cancer: the problem of nonresponding patients

INTRODUCTION

Preoperative treatment is nowadays standard for locally advanced esophagogastric cancer in Europe. Surprisingly, little attention has been paid to nonresponders so far. The aim of our retrospective exploratory study was the comparison of responder, nonresponder, and primary resected patients in respect of outcome considering the tumor entity.

PATIENTS AND METHODS

From 2001-2011, 607 patients with locally advanced esophagogastric carcinoma (adenocarcinoma of the esophagogastric junction (AEG), n = 293; squamous cell cancer (SCC), n = 111; gastric cancer, n = 203) after preoperative treatment (n = 281) or primary resection (n = 326) were included. Histopathological response evaluation (Becker criteria) was available for 263.

RESULTS

A total of 76/263 (28.9 %) were responders (<10 % residual tumor). There was an association of response with increased R0 resections (p < 0.001) but also with a higher complication rate (p = 0.008) compared to nonresponse and primary surgery. Mortality was not influenced. Increased R0 resections after response were confirmed in every tumor entity (AEG, p = 0.010; SCC, p = 0.023; gastric cancer, p = 0.006). Median survival was best for responders with 43.5 months [95 % confidence interval (CI), 27.9-59.1], followed by nonresponders with 24.3 months (95 % CI, 21.6-27.0) and primary resected patients with 20.8 months (95 % CI, 17.7-23.9; p = 0.002). AEG (p = 0.012) and gastric cancer (p = 0.017) revealed identical results, but in the subgroup of SCC, the survival of nonresponders (median, 11.6 months; 95 % CI, 6.9-16.3) was even worse than for primary resected patients (median, 23.8 months; 95 % CI, 1.7-46.0; p = 0.012).

CONCLUSION

The histopathological response rate was low. Generally, nonresponding patients with AEG or gastric cancer seem not to have a disadvantage compared to primary resected patients, but nonresponders with SCC have a worse prognosis, which strengthens the demand for a critical patient selection in surgery for this tumor entity.

[Mechanisms of cell death. Novel insights and implications for tumor pathology]

During tumorigenesis cancer cells acquire certain features allowing for sustained growth and circumvention of programmed cell death. For decades cancer research has been focused on the molecular mechanisms of apoptosis and how to overcome apoptosis resistance in tumor cells. Meanwhile, novel types of programmed cell death have turned out to be important for both physiological and pathological processes. Recent findings imply that induction of alternative forms of programmed cell death, such as necroptosis, might be used as a therapeutic approach to overcome therapy resistance in cancer.

Verrucous carcinoma in epidermolysis bullosa simplex is possibly associated with a novel mutation in the keratin 5 gene

Epidermolysis bullosa simplex (EBS) is mainly caused by mutations in the KRT5 and KRT14 genes. Squamous cell carcinoma (SCC) represents the second most frequent skin neoplasia with complex aetiology. The molecular events disrupting the orchestrated interplay between the cytoskeleton, cell adhesion molecules and signalling proteins are ill understood in SCC. We describe the molecular background and the unusual course of the disease in a patient with EBS Dowling-Meara, severe keratoderma and a massive verrucous carcinoma. Skin and tumour samples from the patient were analysed using light microscopy, immunohistochemistry and immunofluorescence mapping. Mutation analysis of the KRT5 and KRT14 genes identified the novel KRT5 mutation p.E477D. Invasive tumour areas were characterized by downregulation of keratins 5 and 14, reduced and irregular desmocollin-2 expression and increased expression of keratins 6, 16 and 17. Levels of Ki-67 were increased and levels of E-cadherin strongly reduced in the tumour tissue. In this case a novel KRT5 mutation led to increased fragility of keratinocytes. Desmosome and adherens junctions were destabilized, which may trigger keratinocyte-mediated inflammation, possibly via p120-catenin-dependent signalling, suggesting a link between a keratin mutation and SCC, which adds weight to the hypothesis that disturbance of the cytoskeleton represents a major cause in the appearance of the malignant phenotype. Some individuals with EBS may be at risk of developing secondary SCC.