Updates in SJS/TEN: collaboration, innovation, and community

Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN) is a predominantly drug-induced disease, with a mortality rate of 15-20%, that engages the expertise of multiple disciplines: dermatology, allergy, immunology, clinical pharmacology, burn surgery, ophthalmology, urogynecology, and psychiatry. SJS/TEN has an incidence of 1-5/million persons per year in the United States, with even higher rates globally. One of the challenges of SJS/TEN has been developing the research infrastructure and coordination to answer questions capable of transforming clinical care and leading to improved patient outcomes. SJS/TEN 2021, the third research meeting of its kind, was held as a virtual meeting on August 28-29, 2021. The meeting brought together 428 international scientists, in addition to a community of 140 SJS/TEN survivors and family members. The goal of the meeting was to brainstorm strategies to support the continued growth of an international SJS/TEN research network, bridging science and the community. The community workshop section of the meeting focused on eight primary themes: mental health, eye care, SJS/TEN in children, non-drug induced SJS/TEN, long-term health complications, new advances in mechanisms and basic science, managing long-term scarring, considerations for skin of color, and COVID-19 vaccines. The meeting featured several important updates and identified areas of unmet research and clinical need that will be highlighted in this white paper.

Stevens Johnson Syndrome: Past, Present, and Future Directions Gynecologic Manifestations and Management in SJS/TEN

Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe mucocutaneous hypersensitivity disorders characterized by sudden onset epidermal necrosis. Acute manifestations of SJS/TEN often include vulvovaginal erosions, ulcerations, vaginal discharge, bleeding, vaginal pain, dysuria, and urinary retention. If not treated, this can lead to complications such as vulvovaginal adhesions, vaginal stenosis or dryness, pain, dyspareunia, bleeding, and adenosis. Even with adequate treatment, there are lasting impacts including difficulty with vaginal exams and psychological distress. Early recognition and treatment of vulvovaginal involvement are crucial to preventing severe sequelae. Despite the potentially devastating consequences of genitourinary involvement of SJS/TEN, involvement of the mucocutaneous surfaces of the vulva and vagina is inconsistently documented, and protocols for treatment and follow-up are not well-established. The treatment of vulvovaginal involvement relies largely on expert opinion, and there is little data on the efficacy of suggested management. The goal of this review was to identify whether establishing a clinical pathway increased treatment of vulvovaginal SJS/TEN and to optimize our standardized protocol to prevent genitourinary sequelae.

Methods

We conducted a retrospective chart review of female patients with SJS/TEN at Harborview Medical Center, University of Washington from 2008 to 2021. Demographic and clinical data including gynecologic consultation, exam findings, treatment regimens, and outpatient follow-up were collected from the electronic medical record. We compared data before and after implementation of a clinical care pathway in 2017.

Results

We reviewed a total of 88 charts of women with possible SJS/TEN between 2008 and 2021. Of these 88 charts, 77 were found to have clear biopsy proven diagnosis of SJS/TEN. A total of 42 patients were found to have vulvovaginal involvement (55%) and gynecology was consulted in 43% of cases. 50% of patients (n = 21) with vulvovaginal involvement were recommended treatment with vaginal dilators and steroid ointment and 34% of patients with genital involvement received no treatment.

Between 2008 and May of 2017 (pre-protocol), we found 55 patients with SJS/TEN. 55% of patients (n = 29) had vulvovaginal involvement (n = 26 vulvar, n = 21 vaginal). Gynecology was only consulted in 26% (n = 14) of patients. Of the 21 females with vaginal involvement, only 38% (n = 8) had dilators/vaginal molds with steroid ointment recommended. Of the 26 females with vulvar involvement, 31% (n = 8) had no vulvar treatment recommendations with the remaining 69% having some documentation that ranged from gauze placement only (19%) to topical lidocaine, barrier cream, antibiotic or antifungal cream/ ointment, lubricant, or topical steroid ointment (50%). Menstrual suppression was recommended in 38% (n = 9) of menstruating females. An antifungal medication was only prescribed in 4% of patients.

Following implementation of the clinical pathway for the treatment of SJS/TEN in 2017, 22 females with SJS/TEN were identified. 72% (n = 16) had documented vulvovaginal involvement (n = 16 vulvar, n = 9 vaginal). Gynecology consultations took place in 86% (n = 19) of patients. We identified several improvements after implementation of the protocol. Gynecology consults overall increased from 26% pre-, to 86% post-protocol. For patients with vulvovaginal involvement, consultations were completed in 93% compared to 50% prior to protocol. Of note, the finding of vulvovaginal lesions increased from 53 to 72%. Dilator use with topical steroid ointment was consistently recommended, as was antifungal use and menstrual suppression.

Conclusion

Having a protocol in place for treatment of female patients with SJS/TEN increased the consistency of Gynecologic consultation and the documentation and treatment of vulvovaginal SJS/TEN. We identified the need to improve clinical follow-up after discharge from the hospital, which could be arranged as multidisciplinary visits and would be a good option to assess long-term outcomes (pain, sexual activity, etc.). With regards to future directions, we are in the process of assessing long-term data on quality of life and sexual functioning. The impact of treatment in the acute setting on the development of chronic sequelae needs to be established, as does the management of long-term sequelae like vaginal dryness, pain, dyspareunia. The role of local estrogen and vaginal laser still needs to be explored. Pelvic floor physical therapy might play a significant role in rehabilitation and has yet to be studied.

Imiquimod treatment of vulvar melanoma in situ invading the urethra

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Surgical approach is standard of care, topical imiquimod still experimental for mucosal melanoma.

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Imiquimod beneficial for local control of disease if surgery not an option for MIS of vulva/ vagina.

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In situ and invasive vulvovaginal melanoma have a high risk for recurrence even years later.

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Long-term follow-up after topical imiquimod treatment needed as metastasis can arise years later.

The primary treatment of both in situ and invasive vulvar melanoma is wide local excision of the primary neoplasm. However, this can be a surgical challenge for size, multifocal presentation with proximity to urethra or anus and tendency for local recurrence. The data on adjuvant therapy for vulvar MIS is very limited.

A 69-year-old patient with melanoma of the vulva underwent a simple vulvectomy with positive margins in peri-clitoral area, followed by modified radical vulvectomy and bilateral inguinofemoral sentinel lymph node dissection with negative margins. She was later diagnosed with MIS of the vulva on different locations and had multiple wide local excisions over several years. One lesion was close to the urethra and a complete excision was difficult. Topical imiquimod × 16 weeks (5% cream) was given. The regimen was augmented from 3 to 5 times weekly. Complete resolution was found at 16 weeks and patient was disease free for 4 years. Recently however, a vaginal melanoma was detected.

Imiquimod appeared to be beneficial in the treatment of melanoma in situ of the vulva/ vagina when surgical options were not feasible producing local control of disease with the remaining risk for local and distant metastasis. Metastasis can appear years later, therefore long-term follow-up of patients treated with topical imiquimod is needed.

GABA-from Inhibition to Cognition: Emerging Concepts

Neural functioning and plasticity can be studied on different levels of organization and complexity ranging from the molecular and synaptic level to neural circuitry of whole brain networks. Across neuroscience different methods are being applied to better understand the role of various neurotransmitter systems in the evolution of perception and cognition. GABA is the main inhibitory neurotransmitter in the adult mammalian brain and, depending on the brain region, up to 25% of the total number of cortical neurons are GABAergic interneurons. At the one end of the spectrum, GABAergic neurons have been accurately described with regard to cell morphological, molecular, and electrophysiological properties; at the other end researchers try to link GABA concentrations in specific brain regions to human behavior using magnetic resonance spectroscopy. One of the main challenges of modern neuroscience currently is to integrate knowledge from highly specialized subfields at distinct biological scales into a coherent picture that bridges the gap between molecules and behavior. In the current review, recent findings from different fields of GABA research are summarized delineating a potential strategy to develop a more holistic picture of the function and role of GABA.

Characterization of slow cycling corneal limbal epithelial cells identifies putative stem cell markers

In order to identify reliable markers of corneal epithelial stem cells, we employed an inducible transgenic “pulse-chase” murine model (K5Tta × TRE-H2BGFP) to localize, purify, and characterize slow cycling cells in the cornea. The retention of GFP labeling in slowly dividing cells allowed for localization of these cells to the corneal limbus and their subsequent purification by FACS. Transcriptome analysis from slow cycling cells identified differentially expressed genes when comparing to GFP^- faster-dividing cells. RNA-Seq data from corneal epithelium were compared to epidermal hair follicle stem cell RNA-Seq to identify genes representing common putative stem cell markers or determinants, which included Sox9, Fzd7, Actn1, Anxa3 and Krt17. Overlapping retention of GFP and immunohistochemical expression of Krt15, ΔNp63, Sox9, Actn1, Fzd7 and Krt17 were observed in our transgenic model. Our analysis presents an array of novel genes as putative corneal stem cell markers.

Tree shrews at the German Primate Center

Abstract. For many years, Tupaia (family Tupaiidae), most commonly known as tree shrews, have been studied almost exclusively by zoologists resulting in a controversial debate on their taxonomic status among mammals. Today, tree shrews are placed in the order Scandentia; they are valuable, widely accepted and increasingly used model animals as an alternative to rodents and non-human primates in biomedical research. After a brief description on how tree shrews entered science and their taxonomic odyssey, the present article describes the history of the tree shrew (Tupaia belangeri) colony at the German Primate Center and selected aspects of our work with special emphasis on the psychosocial stress model in these animals.

The evolution and complexity of the genes encoding the cytoskeletal proteins of human epidermal cells

In order to explore the differential expression and evolutionary conservation of the genes encoding the cytoskeletal proteins for human epidermal cells, we have constructed a library of bacterial plasmids containing inserts of double-stranded cDNAs complementary to the mRNAs of cultured human epidermal cells. Cloned hybrid plasmids containing 45-95% of the sequences present in keratin, actin, and tubulin mRNAs were isolated and characterized. To identify the cDNAs encoding the four major keratins of human epidermal cells, the clones were initially screened for their ability to hybridize strongly with 32P-labeled cDNA prepared from unfractionated epidermal mRNA (about 30% keratin mRNA). Strongly hybridizing clones were further characterized by positive hybrid selection. Two distinct classes of clones were identified: One class hybridized specifically to the 56 and 58kd keratin mRNAs and one class hybridized specifically to the 46 and 50kd keratin mRNAs. Each class is encoded by a separate multigene family of about 10 genes. The two classes of sequences are conserved throughout vertebrate evolution, indicating the functional importance of each class in filament assembly. Clones containing human cDNA sequences encoding a cytoplasmic actin and alpha-tubulin were selected by hybridization screening using 32P-labeled cloned cDNAs for the mRNAs of beta-actin and alpha-tubulin of embryonic chick brain. The identity of these clones was established by positive hybrid selection and by DNA sequence analysis. Similar to the keratins, the actins and tubulins are also encoded by multigene families which are highly evolutionarily conserved. The availability of cloned cDNAs specific for each of three types of epithelial cytoskeletal proteins allows us to investigate the coordinate expression of their mRNAs during terminal differentiation in human epidermis.

Core body temperature is not a reliable parameter to follow the reproductive cycle in female marmoset monkey (<i>Callithrix jacchus</i>)

Abstract. Marmosets represent an attractive and widely used animal species in biomedical research, and the routine monitoring of female reproductive cycles is often mandatory in the fields of reproductive biology and stem cell research. Today, the established method for the reliable detection of ovulation is the determination of progesterone concentrations from blood samples. This method is based on relatively frequent handling and blood collections; therefore, less invasive alternatives would help to reduce stress on the animals. Here, we investigated whether the core body temperature of marmosets would show a correlation with cycle-dependent hormonal fluctuations, as has been described for humans and other primate species. In particular, the objective was to investigate whether the telemetric recording of core body temperature could replace progesterone measurements as a reliable, less invasive method for the detection of ovulation in these animals. Here we show that the core body temperature parameters in female marmosets were characterized by frequent variations, but they were not related to particular days or phases during the reproductive cycle. Therefore, the recording of core body temperature in our controlled standard experimental setting is not an appropriate method to monitor the reproductive cycle in female marmosets, and cannot replace serum progesterone measurement as a state-of-the-art method.

Investigation of different yeast strains for the detoxification of ochratoxin A

High concentrations of ochratoxin A (OTA) in feed lead to growth depression in animals. It has been reported that binders can be used for deactivating aflatoxins but not for other mycotoxins without negatively influencing the animals health. In this study a strain from the genus ofTrichosporon with the ability to cleave ochratoxin A very selectively into phenylalanine and the non-toxic ochratoxin α (OTα) could be isolated. This strain was selected from a pool of OTA detoxifying microorganism by carrying out several investigations.Trichosporon sp. nov. can be fermented and stabilized. In a feeding trial with broilers lyophilizedTrichosporon-cells could compensate performance losses caused by OTA.

Methylation and expression analyses of the 7q autism susceptibility locus genes MEST , COPG2, and TSGA14 in human and anthropoid primate cortices

The autism susceptibility locus on human chromosome 7q32 contains the maternally imprinted MEST and the non-imprinted COPG2 and TSGA14 genes. Autism is a disorder of the 'social brain' that has been proposed to be due to an overbalance of paternally expressed genes. To study regulation of the 7q32 locus during anthropoid primate evolution, we analyzed the methylation and expression patterns of MEST, COPG2, and TSGA14 in human, chimpanzee, Old World monkey (baboon and rhesus macaque), and New World monkey (marmoset) cortices. In all human and anthropoid primate cortices, the MEST promoter was hemimethylated, as expected for a differentially methylated imprinting control region, whereas the COPG2 and TSGA14 promoters were completely demethylated, typical for transcriptionally active non-imprinted genes. The MEST gene also showed comparable mRNA expression levels in all analyzed species. In contrast, COPG2 expression was downregulated in the human cortex compared to chimpanzee, Old and New World monkeys. TSGA14 either showed no differential regulation in the human brain compared to chimpanzee and marmoset or a slight upregulation compared to baboon. The human-specific downregulation supports a role for COPG2 in the development of a 'social brain'. Promoter methylation patterns appear to be more stable during evolution than gene expression patterns, suggesting that other mechanisms may be more important for inter-primate differences in gene expression.

A high density of human communication-associated genes in chromosome 7q31-q36: differential expression in human and non-human primate cortices

The human brain is distinguished by its remarkable size, high energy consumption, and cognitive abilities compared to all other mammals and non-human primates. However, little is known about what has accelerated brain evolution in the human lineage. One possible explanation is that the appearance of advanced communication skills and language has been a driving force of human brain development. The phenotypic adaptations in brain structure and function which occurred on the way to modern humans may be associated with specific molecular signatures in today's human genome and/or transcriptome. Genes that have been linked to language, reading, and/or autism spectrum disorders are prime candidates when searching for genes for human-specific communication abilities. The database and genome-wide expression analyses we present here revealed a clustering of such communication-associated genes (COAG) on human chromosomes X and 7, in particular chromosome 7q31-q36. Compared to the rest of the genome, we found a high number of COAG to be differentially expressed in the cortices of humans and non-human primates (chimpanzee, baboon, and/or marmoset). The role of X-linked genes for the development of human-specific cognitive abilities is well known. We now propose that chromosome 7q31-q36 also represents a hot spot for the evolution of human-specific communication abilities. Selective pressure on the T cell receptor beta locus on chromosome 7q34, which plays a pivotal role in the immune system, could have led to rapid dissemination of positive gene variants in hitchhiking COAG.

Improving the energy and nutrient supply for common marmoset monkeys fed under long-term laboratory conditions

BACKGROUND

Current knowledge about the optimal energy and nutrient supply for common marmoset monkeys (Callithrix jacchus) is scarce, and more information is needed for establishing the underlying nutritional concepts for facilitating longevity of this species as laboratory animals for biomedical research.

METHODS

Two feeding experiments were conducted to yield fundamental data about feed acceptance, real feed intake, and feed preferences under laboratory conditions. Newly developed feeding concepts for marmoset monkeys were also examined in preliminary investigations to compare the outcomes with those of a commercial pelletized mixed feed.

RESULTS

The first experiments showed preferences for main protein sources in the diets studied, specifically that plant proteins are more accepted than fish meal or egg protein as the main protein source. Several aroma supplements did not modify the acceptance and feed intake markedly.

CONCLUSIONS

The newly developed feeding concept yielded promising preliminary data for long-term studies of energy and nutrient supply under laboratory conditions. However, studies of the fundamental requirements are still needed.

Bronchoconstriction in nonhuman primates: a species comparison

Bronchoconstriction is a characteristic symptom of various chronic obstructive respiratory diseases such as chronic obstructive pulmonary disease and asthma. Precision-cut lung slices (PCLS) are a suitable ex vivo model to study physiological mechanisms of bronchoconstriction in different species. In the present study, we established an ex vivo model of bronchoconstriction in nonhuman primates (NHPs). PCLS prepared from common marmosets, cynomolgus macaques, rhesus macaques, and anubis baboons were stimulated with increasing concentrations of representative bronchoconstrictors: methacholine, histamine, serotonin, leukotriene D₄ (LTD₄), U46619, and endothelin-1. Alterations in the airway caliber were measured and compared with previously published data from rodents, guinea pigs, and humans. Methacholine induced maximal airway constriction, varying between 74 and 88% in all NHP species, whereas serotonin was ineffective. Histamine induced maximal bronchoconstriction of 77 to 90% in rhesus macaques, cynomolgus macaques, and baboons and a lesser constriction of 53% in marmosets. LTD₄ was ineffective in marmosets and rhesus macaques but induced a maximum constriction of 44 to 49% in cynomolgus macaques and baboons. U46619 and endothelin-1 caused airway constriction in all NHP species, with maximum constrictions of 65 to 91% and 70 to 81%, respectively. In conclusion, PCLS from NHPs represent a valuable ex vivo model for studying bronchoconstriction. All NHPs respond to mediators relevant to human airway disorders such as methacholine, histamine, U46619, and endothelin-1 and are insensitive to the rodent mast cell product serotonin. Only PCLS from cynomolgus macaques and baboons, however, responded also to leukotrienes, suggesting that among all compared species, these two NHPs resemble the human airway mechanisms best.

Stress revisited: a critical evaluation of the stress concept

With the steadily increasing number of publications in the field of stress research it has become evident that the conventional usage of the stress concept bears considerable problems. The use of the term 'stress' to conditions ranging from even the mildest challenging stimulation to severely aversive conditions, is in our view inappropriate. Review of the literature reveals that the physiological 'stress' response to appetitive, rewarding stimuli that are often not considered to be stressors can be as large as the response to negative stimuli. Analysis of the physiological response during exercise supports the view that the magnitude of the neuroendocrine response reflects the metabolic and physiological demands required for behavioural activity. We propose that the term 'stress' should be restricted to conditions where an environmental demand exceeds the natural regulatory capacity of an organism, in particular situations that include unpredictability and uncontrollability. Physiologically, stress seems to be characterized by either the absence of an anticipatory response (unpredictable) or a reduced recovery (uncontrollable) of the neuroendocrine reaction. The consequences of this restricted definition for stress research and the interpretation of results in terms of the adaptive and/or maladaptive nature of the response are discussed.

Chronic psychosocial stress alters NPY system: different effects in rat and tree shrew

The neuropeptide Y (NPY) system has been largely studied in relation to affective disorders, in particular for its role in the mechanisms regulating the pathophysiology of anxiety and depression and in the stress-related behaviours. Although NPY has been previously investigated in a variety of animal models of mood disorders, the receptor subtype mainly involved in the modulation of the stress response has not been identified. In the present study, the chronic psychosocial stress based on the resident-intruder protocol-an ethologically relevant paradigm known to induce behavioural and endocrine modifications which mimic depression-like symptoms-was used. Two different species were investigated: rat and tree shrew (Tupaia belangeri); the latter is regarded as an intermediate between insectivores and primates and it was chosen in this study for its pronounced territoriality. In these animals, the regulation of NPY and of Y(1), Y(2) and Y(5) receptors mRNA expression was evaluated after chronic stress and chronic antidepressant treatment by in situ hybridization in selected brain regions known to be involved in the pathophysiology of mood disorders. The animals were exposed to psychosocial stress for 35 days and concomitant daily fluoxetine treatment (10 mg/kg for rats and 15 mg/kg for tree shrews) after the first week of stress. The results confirmed a major role for hippocampal and hypothalamic NPY system in the pathophysiology of mood disorders. Although there were no evident differences between rat and tree shrew in the NPY system distribution, an opposite effect of chronic psychosocial stress was observed in the two species. Moreover, chronic antidepressant treatment was able to counteract the effects of stress and restored basal expression levels, suggesting the utility of these paradigms as preclinical models of stress-induced depression. Overall, although evident species differences were found in response to chronic psychosocial stress, the present study suggests a role for NPY receptors in the stress response and in the action of antidepressant drugs, providing further support for an involvement of this neuropeptidergic system in the pathophysiology of depression and anxiety.

Regulation of adult neurogenesis by stress, sleep disruption, exercise and inflammation: Implications for depression and antidepressant action

Adult hippocampal neurogenesis, a once unorthodox concept, has changed into one of the most rapidly growing fields in neuroscience. The present report results from the ECNP targeted expert meeting in 2007 during which cellular plasticity changes were addressed in the adult brain, focusing on neurogenesis and apoptosis in hippocampus and frontal cortex. We discuss recent studies investigating factors that regulate neurogenesis with special emphasis on effects of stress, sleep disruption, exercise and inflammation, a group of seemingly unrelated factors that share at least two unifying properties, namely that they all regulate adult hippocampal neurogenesis and have all been implicated in the pathophysiology of mood disorders. We conclude that although neurogenesis has been implicated in cognitive function and is stimulated by antidepressant drugs, its functional impact and contribution to the etiology of depression remains unclear. A lasting reduction in neurogenesis following severe or chronic stress exposure, either in adult or early life, may represent impaired hippocampal plasticity and can contribute to the cognitive symptoms of depression, but is, by itself, unlikely to produce the full mood disorder. Normalization of reductions in neurogenesis appears at least partly, implicated in antidepressant action.

Multiple Subtypes of HER-2/Neu-Positive Metastatic Breast Cancer

Background: Using IHC or FISH to select patients for trastuzumab-based therapy, only half of HER2-positive patients show evidence of response. In vitro data implicate HER2:HER3 heterodimers and p95HER2 (p95), the truncated 95-kilodalton C-terminal fragment of HER-2 lacking the trastuzumab binding site, as mediators of resistance to trastuzumab at the receptor level. We have previously reported that central FISH-positive patients with low HER2 protein expression by VeraTag had significantly reduced response to trastuzumab compared to patients who had FISH-positive tumors with high HER2 protein expression (Lipton, SABCS 2008). Adding quantitative measurements of HER3 and p95, we offer evidence for the existence of multiple sub-types of HER2-positive tumors that respond differently to trastuzumab.Methods: Using the VeraTag assay, quantitative protein measurements of HER2, HER3, and p95 were made in FFPE specimens from a cohort of patients with metastatic breast cancer (MBC) and correlated with time to progression (TTP) and overall survival (OS) following treatment with first-line trastuzumab using Kaplan-Meier (KM) and Cox proportional hazards regression analyses.Results: Measurements of HER2 (H2T), HER3 (H3T) and p95 were made in FFPE tumor samples from 95 patients treated with first-line trastuzumab for metastatic breast cancer. Within the group that overexpressed HER2 by the VeraTag Assay (n=60), a group with highly overexpressed HER2 (n=15) had shorter TTP and OS than those that had moderate HER2 overexpression (median TTP 4.6 vs. 12 mos, HR=2.1; p=0.011; median OS 29 vs. 40 mos, HR=2.0; p=0.047). Within the subgroup with moderate H2T overexpression (n=45), bivariate Cox analyses demonstrated that p95 and H3T were independent predictors of TTP (p95 HR=2.1; p=0.031; H3T HR=3.5; p=0.0037). For OS, p95 was significant and H3T showed a strong trend (p95 HR=2.5; p=0.025, H3T HR=2.2; p=0.089). Univariate KM analysis with the p95+ and H3T+ groups combined, gives the results in the table below. These data suggest that HER2-positive breast cancer patients can be classified into at least 4 sub-groups with different outcomes following trastuzumab treatment.Conclusions: These data suggest the existence of multiple subgroups of HER2-positive patients expressing varying HER2, p95, and HER3 levels that experience different clinical outcomes following treatment with trastuzumab. Furthermore, the association of HER3 and p95 overexpression with poor response to trastuzumab in otherwise HER2-positive tumors suggests possible treatment approaches with combinations of targeted therapies.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2030.

A molecular blueprint of gene expression in hippocampal subregions CA1, CA3, and DG is conserved in the brain of the common marmoset

Recent studies in rodents have shown that there are significant differences in gene expression profiles between the hippocampal subregions CA1, CA3, and DG. These differences in molecular make-up within the hippocampus most likely underlie the differences in morphology, physiology, and vulnerability to insults that exist between the subregions of the hippocampus and are as such part of the basic molecular architecture of the hippocampus. The aim of this study was to investigate at large scale whether these subregional differences in gene expression are conserved in the hippocampus of a nonhuman primate, the common marmoset. This study is very timely, given the recent development of the first marmoset-specific DNA microarray, exclusively containing sequences targeting transcripts derived from the marmoset hippocampus. Hippocampal subregions CA1, CA3, and DG were isolated by laser microdissection and RNA was isolated, amplified, and hybridized to the marmoset-specific microarray (EUMAMA) containing more than 1,500 transcripts expressed in the adult marmoset hippocampus. Large differences in expression were observed in particular between the DG region and both pyramidal subregions. Moreover, the subregion-specific patterns of gene expression showed a remarkable conservation with the rodent brain both in terms of individual genes and degree of differential expression. To our knowledge, this is the first study investigating large scale hippocampal gene expression in a nonhuman primate. The obtained expression profiles not only provide novel data on the expression of more than 1,500 transcripts per hippocampal subregion but also are of potential interest to neuroscientists interested in the role of the different subregions in learning and memory in the nonhuman primate brain.

Incidence of humoral sensitization in HLA partially mismatched hematopoietic stem cell transplantation

As part of the 15th International Histocompatibility and Immunogenetics Workshop (IHIWS), seven centers participated in a collaborative project to determine whether any significant humoral sensitization occurred post-transplant among recipients of HLA partially mismatched hematopoietic cell transplants (HCTs). A total of 140 donor/recipient pairs were enrolled with a total of 367 pre-and post-transplant sera analyzed. The majority of the samples (69.1%) were obtained within 30-90 days post-HCT. HLA-specific antibodies were defined using single antigen bead assays on a Luminex platform with a positive cutoff value of 1000 normalized median fluorescence intensity (MFI). There was an overall incidence of post-HCT sensitization toward donor HLA mismatches of 5.7%; however, all cases were among recipients of one HLA haplotype-mismatched grafts under nonmyeloablative, pre-transplant conditioning. Among the one haplotype-mismatched recipients, 15.7% (8/51) developed donor HLA-specific antibodies and 29.4% also had antibodies directed toward third party HLA antigens. Among the donor-specific antibodies, 9.8% were directed toward HLA class I antigens; 7.8% were against class II antigens; and 2.0% had both class I and II specificity. The relative strength of post-transplant antibodies was low with no significant difference in the mean maximum MFI values between third party and donor-specific antibodies. Because only a small number (10.2%) of the post-transplant samples were obtained 180 days or more post-HCT, longer term study is needed to evaluate any clinical relevance of these low-to-moderate levels of donor-specific antibody in one haplotype-mismatched recipients, as well as to determine whether any other antibodies occur at later times.

Use of pretreatment serum CA9 (carbonic anhydrase 9) to predict PFS and survival in trastuzumab-treated metastatic breast cancer

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Background: Approximately half of HER2-positive breast cancer patients will respond to first-line trastuzumab-containing therapy. However, in those patients with an initial trastuzumab response, most will progress within a year with acquired resistance. Since trastuzumab treatment is also now used in the HER2-positive adjuvant breast cancer setting, trastuzumab resistance will continue to be a vexing clinical problem, and better predictive and prognostic biomarkers are urgently needed. Methods: Serum HER2, tissue inhibitor of metalloproteinase-1 (TIMP-1), urokinase-type plasminogen activator (uPA), CA9, VEGF-165, and endoglin were measured using ELISA assays in 66 metastatic breast cancer patients before starting first-line trastuzumab-containing therapy. The HER2, TIMP-1, uPA, CA9, and VEGF-165 ELISAs were from Oncogene Science/Siemens Healthcare Diagnostics, Cambridge, MA; and the endoglin ELISA was from R&D Systems, Minneapolis, MN. Progression-free (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method and Cox modeling with continuous pretreatment serum biomarker variables. Results: Pretreatment serum HER2 (p= 0.005), TIMP-1 (p< 0.0001), uPA (p= 0.006), endoglin (p= 0.008), and CA9 (p <0.0001) were all significant as univariate continuous biomarkers for predicting PFS to first-line trastuzumab-containing therapy, but VEGF was not. In multivariate analysis for PFS with all six biomarkers, only serum CA9 (p= 0.002) was a significant independent covariate. For OS, pretreatment serum HER2 (p= 0.018), TIMP-1 (p< 0.0001), uPA (p< 0.0001), endoglin (p= 0.002), and CA9 (p< 0.0001) were all significant as univariate continuous biomarkers for prognosis, but serum VEGF was not. In multivariate analysis for OS with all six biomarkers, only serum CA9 was a significant independent prognostic covariate (p= 0.001). Conclusions: Elevated pretreatment serum CA9 (a marker of hypoxia) predicts reduced progression-free survival and overall survival in metastatic breast cancer patients treated with first-line trastuzumab-containing therapy. These serum biomarkers deserve further study in larger trials of HER2-targeted breast cancer treatment. Supported by a grant from Komen for the Cure.

[Table: see text]

Identification of a subpopulation of metastatic breast cancer patients with very high HER2 expression levels and possible resistance to trastuzumab

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Background: Many HER2-positive patients with metastatic breast cancer (MBC) fail to respond to trastuzumab. We previously reported that precise quantitation of HER2 expression (H2T) by the HERmark assay identified a sub-population of IHC 3+, FISH(+) (positive) patients with low H2T levels that responded poorly to trastuzumab (Lipton, San Antonio Breast Cancer Symposium 2008, abs #32). Here we identify a sub-population of FISH(+) patients with very high H2T levels, that experience clinical outcomes that are indistinguishable from those of FISH(-) (negative) patients with low H2T levels. Methods: The HERmark assay was used to measure H2T in formalin-fixed, paraffin-embedded (FFPE) primary breast tumor specimens from 99 women treated with trastuzumab for MBC. Specimens were also tested by central FISH. A sub-population treatment effect pattern plot (STEPP) was generated to examine the progression-free survival (PFS) rate at 12 months after treatment with trastuzumab across the distribution of H2T. Kaplan-Meier (KM) analyses were performed comparing the PFS of FISH(-), H2T low (log10H2T < 1.25) patients with those of FISH(+), H2T high (log10H2T ≥ 1.95) and FISH(+), H2T intermediate (1.25 < log10H2T < 1.95) groups. Cutoffs were identified by lowest p-value in a positional scanning analysis. Results: The PFS rate improved gradually with increasing H2T in STEPP analyses. At the highest levels of H2T, an abrupt decrease in the PFS rate was observed, consistent with a reduction in susceptibility to trastuzumab. KM analyses demonstrated that patients who were FISH(+), H2T intermediate had a significantly longer PFS than patients who were FISH(-), H2T low (median PFS 12.6 vs. 4.5 mos; HR = 0.34; p < 0.0001). Patients that were FISH(+), H2T high experienced a PFS that was no better than patients that were FISH(-), H2T low (median PFS 4.6 vs. 4.5 mos; HR = 0.87; p = 0.68). Conclusions: Precise quantitation of HER2 expression levels allows the identification of multiple sub-populations of HER2(+) patients that have different clinical outcomes on trastuzumab. MBC patients with very high levels of H2T could represent a sub-group with de novo resistance to trastuzumab who may benefit from combined therapy.

[Table: see text]

Incomplete surgical resection of DCIS results in activation of HER-2 in residual breast cancer cells

e22035

Background: HER-2 amplification and consecutive overexpression is a predictor for poor prognosis in breast cancer patients. In addition, incomplete resection of HER2 overexpressing tumors leads to increased proliferation of residual breast cancer cells. While the local release of cytokines is thought to be responsible for the malignant behaviour of remaining tumor tissue, the exact mechanism is still unknown. Methods: We have analyzed EGFR, activated (p)EGFR, and activated (p)HER2 protein expression in HER2 overexpressing and in non-HER2 overexpressing tumors from patients who underwent breast surgery and consecutive reexcision for involved margins, and compared expression levels by IHC. Results: While overall HER2 protein expression in the initial and the reexcised sample were comparable, we observed an increase in pHER2 in DCIS in both, HER2 overexpressing (16/21 vs 24/24; p=0.018, Chi Square test) and non-HER2 overexpressing tumors (3/28 vs 5/12; p=0.025, Chi Square test). pHER2 was not increased in invasive tumors, regardless on whether the samples had been taken from a HER2 overexpressing (9/25 vs 6/17; p=0.261, Chi Square test), or a non-HER2 overexpressing tumor (1/27 vs 0/8; p=0.581, Chi Square test). EGFR expression was only detected in 1/47 HER2 overexpressing primary tumors and 2/48 non-HER2 overexpressing tumors, and was undetectable in reexcised specimen. Conclusions: Taken together, we have demonstrated an increase in HER2 receptor activation in incompletely resected preinvasive breast cancer. We hypothesize that receptor phosphorylation is caused by growth factor stimulation in response to intraoperative tissue damage, and perioperative inhibition of specific cytokines could become a promising therapeutic strategy.

No significant financial relationships to disclose.

Use of the ErbB2/CEP17 ratio to predict prognosis and response to trastuzumab-based therapy in the metastatic breast cancer setting

11110

Background: Despite patient selection based upon detection of Her-2/neu overexpression by immunohistochemistry (IHC) and/or presence of amplification of the Her-2/neu-encoding erbB2 oncogene measured by FISH, response to trastuzumab-based therapy is only achieved in a subset of patients with Her-2/neu overexpressing breast carcinomas. Exact quantification of erbB2 copy-number relative to chromosome 17 (CEP17) (ErbB2/CEP17 ratio “R”) probably adds further important predictive information. Methods: Clinical data of 137 patients receiving trastuzumab based treatment for Her-2/neu overexpressing (IHC) metastatic breast cancer were analysed. ErbB2/CEP17 ratio (R) was determined by quantitative FISH analysis in original tumor tissue using Vysis PathVysion DNA-based FISH technology. Results: ErbB2/CEP17 (R) provided additional predictive value for progression free survival (PFS) and time to first metastasis (TTM), but not for overall survival (OS) (all from start of trastuzumab containing treatment). The following cutoffs of Her-2/neu were identified: group A: 0–2.2 R (TTM: 49.8; OS: 6.7; PFS: 6.2); group B: 2.2- 6 R (TTM: 26.2; OS: 5.3; PFS: 9.3); group C: >6 CN (TTM: 20.1; OS: 3.9; PFS: 13.7) Kaplan-Maier analysis showed significant longer TTM for group A (p<0.01 vs. B/C), significant longer PFS for group C (p<0.01 vs. A/B). Significant differences in complete response (B/C: 16.9% vs C:44.4%), partial response (B/C: 20.2% vs. C: 33.3%) and progressive disease (B/C: 27% vs. 11.1%) were noted. No significant difference in overall survival between the groups was seen. Conclusions: ErbB/CEP17 R provides important prognostic information and, in metastatic patients, allows one to better predict response to trastuzumab-based treatment than the widely used binary classification of ErbB2 amplification that is based on a cut-off at a copy number of >2.2.

No significant financial relationships to disclose.