“
“Pigtail macaques, Macaca nemestrina (PT), are more susceptible to vaginal

transmission of simian immunodeficiency virus (SIV) and other sexually transmitted diseases (STD) than rhesus macaques (RM). However, comparative studies to explore the reasons for these differences are lacking. Here, we compared differences in hormone levels and vaginal mucosal anatomy and thickness of RM and PT through different stages of the menstrual cycle. Concentrations of plasma estradiol (E2) and progesterone (P4) were determined weekly, and vaginal biopsies examined at days 0 and 14 of the menstrual cycle. Consistent changes in vaginal epithelial thickness occurred at different stages of the menstrual cycle. In both species, the vaginal epithelium was significantly thicker in the follicular than in luteal phase. Keratinized epithelium selleck kinase inhibitor was strikingly much more www.selleckchem.com/products/apo866-fk866.html prominent in RM, especially during the luteal phase. Further, the vaginal epithelium was significantly thinner, and the P4:E2 ratio was higher in PT during luteal

phase than RM. Striking anatomic differences in the vaginal epithelium between rhesus and pigtail macaques combined with differences in P4:E2 ratio support the hypothesis that thinning and less keratinization of the vaginal epithelium may be involved in the greater susceptibility of pigtail macaques to vaginal transmission of SIV or other STD. Bumetanide “
“In systemic lupus erythematosus (SLE), the autoantibodies that form immune complexes (ICs) trigger activation of the complement system. This results in the formation of membrane attack complex (MAC) on cell membrane and the soluble terminal complement complex (TCC). Hyperactive T cell responses are hallmark

of SLE pathogenesis. How complement activation influences the T cell responses in SLE is not fully understood. We observed that aggregated human γ-globulin (AHG) bound to a subset of CD4+ T cells in peripheral blood mononuclear cells and this population increased in the SLE patients. Human naive CD4+ T cells, when treated with purified ICs and TCC, triggered recruitment of the FcRγ chain with the membrane receptor and co-localized with phosphorylated Syk. These events were also associated with aggregation of membrane rafts. Thus, results presented suggest a role for ICs and complement in the activation of Syk in CD4+ T cells. Thus, we propose that the shift in signalling from ζ-chain-ZAP70 to FcRγ chain-Syk observed in T cells of SLE patients is triggered by ICs and complement. These results demonstrate a link among ICs, complement activation and phosphorylation of Syk in CD4+ T cells. Spleen tyrosine kinase (Syk) is a non-receptor tyrosine kinase expressed by haematopoietic cells that play a crucial role in adaptive immunity [1]. Syk activation is important for cellular adhesion, vascular development, osteoclast maturation and innate immune recognition.

The skin is constantly subjected to environmental insults (microbial, chemical and physical) that may trigger immune responses 20. It has been proposed that the presence of NLRP3 in the skin (keratinocytes and tissue resident dendritic cells) provides a first line of defence by enabling the rapid sensing of invading pathogens, thereby triggering an innate immune response via NLRP3 inflammasome activation 21, 22. Sensitising allergens that penetrate the skin surface induce a delayed type hypersensitivity reaction, called contact hypersensitivity (CHS) 23, 24. Evidence has been presented for the involvement of NOD-like receptors (NLR) as well as IL-1β,

IL-18 and caspase-1 in the mouse CHS

model 25, 26. Recent work has also suggested that IL-18 plays an important role by distinguishing the presence Proteasome inhibitor of contact allergens from irritants 27 (Table 1). The outcome of skin immune responses with respect to tolerance or immunity is dependent on skin NLRP3 inflammasome activation, and secreted IL-1β and IL-18 may regulate the quality of an allergen-specific https://www.selleckchem.com/products/DAPT-GSI-IX.html T-cell response in CHS 25. Furthermore, mice deficient in IL-1β have impaired CHS to trinitrochlorobenzone 28. These discoveries suggest that modulation of the NLRP3 inflammasome may offer a therapeutic strategy to modulate T-cell responses in patients suffering from allergic CHS. Excitingly, manipulation of the NLRP3 inflammasome may also offer a perspective to induce tolerance towards a given contact allergen. Type 2 diabetes (T2D) occurs when beta cells in the pancreas fail to produce sufficient insulin to overcome insulin resistance. Several lines of evidence support the role of IL-1β in the pathogenesis of T2D; expression of the IL-1Ra is reduced in the pancreatic islets of these patients, with IL-1β being produced in response to high glucose concentrations,

leading to decreased cell proliferation and apoptosis 29. Larsen et al. have reported that anakinra treatment results in decreased glycated haemoglobin (HbA1c) levels and increased insulin production in T2D patients 30. An IL-1β antibody, Xoma 052, was shown to restore glycemic control in T2D patients eltoprazine in a double-blind, placebo-controlled, dose-escalation study 31. In this regard, it is also relevant that glyburide, a sulphonylurea drug used to treat T2D, inhibits the NLRP3 inflammasome 32. T2D is a burgeoning global health problem and this advance in understanding the pathogenesis will offer novel therapeutic avenues in the future. Inflammation appears to provide a local environment in which many tumours flourish and IL-1β has a key role in this process 33. Inflammasome-mediated pathogen recognition 34 provides a potential, but as yet unproven, link between infection-induced inflammation and cancer.

327, p<0.05, MS: r2=0.446, p<0.05). Of interest, the Treg-mediated inhibition of Tconv proliferation also positively correlated with IL-7Rα-MFIs on Tconv (HC: r2=0.175, p<0.05 MS: r2=0.587, p<0.01; Fig. 3), suggesting that IL-7Rα expression by affecting

frequencies of circulating RTE-Treg also interferes with Treg function. Proliferative responses of stimulated and unstimulated Tconv were comparable in samples obtained from MS patients and healthy donors. We measured sIL-7Rα in plasma specimens obtained from MS patients (n=20, 12 with active disease, 8 in remission) and age- and sex-matched control inidividuals (n=17) using an in-house ELISA protocol and IL-7 levels with a conventional ELISA Kit as described in the Materials and methods section. We found an inverse correlation between IL-7 plasma levels and IL-7Rα-MFIs on total Tconv in patients with MS (IL-7: HC: r2=0.142, p=0.103; MS: r2=0.252, p=0.027;

Fig. 4B). Concentrations of both IL-7 and sIL-7Rα were find more elevated in 20 patient-derived samples as compared to 17 HC-derived Sotrastaurin molecular weight samples, which was statistically significant for IL-7 only (IL-7 [pg/mL]: HC 5.1±1.5, MS 11.2±5.9, p=0.050; sIL-7Rα [ng/mL]: HC 107.5±40.6, MS 145.0±53.7, p=0.161; Fig. 4A). Enhanced IL-7 and sIL-7Rα plasma levels were detectable in both patients with active and inactive disease. TSLP and TSLPR-expressing MDCs were previously shown to be critically involved in thymic Treg development 13. Therefore, we analyzed surface expression levels of TSLPR on circulating MDCs in blood samples obtained from MS patients (n=12, 8

with active disease, 4 in remission) and age- and sex-matched normal donors (n=11). TSLPR-MFIs were significantly lower on patient-derived MDCs (HC 96.0±15.9, MS 59.6±17.4; p<0.01; Fig. 5) and did not differ between RRMS patients with active or stable Fluorometholone Acetate disease. In addition, expression levels of IL-7Rα and TSLPR strongly correlated in both study cohorts (MS: r2=0.57, p<0.05; HC: r2=0.61, p<0.05; not depicted). It was previously shown, that 10–30% of peripheral T cells and up to 99% of human Treg express two distinct TCR-Vα chains 21. Here, in both study cohorts (HC: n=33, MS: n=56) approximately a quarter of total Tconv harbored TCRs with dual specificity (HC: 31.9±14.0%, MS: 29.6±18.2%, p=0.47). In contrast, 85.6±17.1% of control-derived, but only 55.8±31.2% of patient-derived Treg expressed two TCR-Vα chains (p<0.01; Fig. 6A). Overall, there was a strong correlation of IL-7Rα-MFIs of Tconv and TSLPR-MFIs on MDCs with the amount of dual TCR specific Treg in both patients and control donors (IL-7Rα: HC: r2=0.247, p=0.011; MS: r2=0.355, p=0.008, Fig. 6B; TSLPR: HC: r2=0.214, p=0.031; MS: r2=0.333, p=0.016; not depicted). Screening for rs6897932-SNP 15–18 associated with MS, type 1 diabetes and chronic inflammatory arthropathies 19 was performed by SNAP-shot PCR.

[25] This CCR5 is related to a highly

suppressive phenotype and may be a marker for those cells activated by paternal alloantigens.[55] Alectinib Chemokine ligand 4 (CCL4), a CCR5 ligand, is intensively expressed in the pregnant uterus and is involved in the further selective accumulation of CCR5+ regulatory T cells during pregnancy.[56] Additionally, human chorionic gonadotropin (hCG) is suggested as a hormone trafficking regulatory T cells in the fetomaternal interface. As regulatory T cells have LH/CG receptors, both hCG-producing JEG3 cells and first trimester trophoblast cells efficiently attracted regulatory T cells.[57] This is another mechanism attracting regulatory T cells in the embryo-implanted deciduas. During pregnancy, peripheral blood CD4+ CD25+ and CD4+ CD25+ Foxp3+ regulatory T cells increase gradually during 1st and 2nd trimester and then decrease in the 3rd trimester and postpartum.[58, 59] A recent study has found that suppressive activity of regulatory T cells from normal pregnant women was significantly increased in 1st and 2nd trimester, but significantly

weak in 3rd trimester and at term as compared with that of non-pregnant women.[60] Published data comparing endometrial and decidual regulatory T cells between non-pregnant and pregnant women or during pregnancy were not found. In a study in women with spontaneous pregnancy loss, CD4+ CD25high regulatory T cells were preferentially recruited into the deciduas as compared to circulating regulatory T cells.[61] Some ex vivo studies N-acetylglucosamine-1-phosphate transferase have demonstrated that high estradiol this website concentration during pregnancy promoted proliferation of human regulatory T cells without altering suppressive phenotypes[53] and pregnancy estradiol level expanded regulatory T cells and increased Foxp3 expression in mice.[62] It is still unknown whether Th17 cells fluctuate during a menstrual cycle. The findings of Th17 cells during pregnancy are inconsistent.

Santner-Nanan et al.[63] have found lower Th17/regulatory T-cell ratio and lower Th17 cell level during pregnancy than those of non-pregnant women. However, several reports have published that circulating Th17 cells were not different between non-pregnant state and each trimester[51] or between non-pregnant period and a certain period of pregnancy.[64, 65] Nakashima et al.[51] showed that the proportion of decidual Th17 cells was significantly higher than that of circulating Th17 cells in the first trimester. Furthermore, the Th17/Foxp3+ regulatory T-cell ratio was decreased in normal 2nd and 3rd trimester pregnant women as compared to that in healthy non-pregnant women.[66] Further studies are warranted regarding normal physiology of Th17 cells in women in reproductive age. Only a few regulatory T-cell studies in women with infertility have been published so far.

, 1997; Victor et al., 1999; Ramaswamy et al., 2000), the mutations in the first DAPT clinical trial base of codon 306 are most likely to be GTG (Val) or CTG (Leu) and the mutations in the third base of codon 306 are most likely to be ATA (Ile), which was detected in nine ethambutol-resistant isolates due to embB306 mutations. Our study identified 12 (12%) MDR isolates; six of these are classified as MDR-TB, three were resistant to both isoniazid and rifampicin, and the other three were resistant to all three drugs tested. The simultaneous resistance to isoniazid and ethambutol that was detected in 3% of the isolates is in

agreement with previous reports (Madison et al., 2002; Yang et al., 2005), and the simultaneous resistance to rifampicin and ethambutol detected in 3% of the isolates is consistent with a previous study (Yang et al., 2005). Furthermore, five isolates monoresistant to isoniazid were detected; similar results were reported by earlier studies (Kapur et al., 1994; Schilke et al., 1999). None of our isolates showed monoresistance to ethambutol, as has been reported earlier (Van Rie et al., 2001; Parsons et al., 2005). Moreover, the present study detected two rifampicin-monoresistant isolates. Although rare, resistance to rifampicin is increasing because of widespread use that results in selection of resistant mutants, and is found in cases noncompliant with tuberculosis

treatment (Sandman et al., 1999). In this context, resistance to rifampicin can be assumed selleck to be a surrogate marker for MDR-TB

(Somoskovi et al., 2001; Mokrousov et al., 2003). The new drug-resistant isolates detected in the current study compared with the DST method might be explained by the specificity of the Flavopiridol (Alvocidib) primers used in the PCR technique, and the possibility of inappropriate preparation of the inoculum size used in the DST method (Mitchison, 2005). In addition, a single mutation might generate a different resistant phenotype. The presence of mutations within the rpoB locus that are not associated with resistance may influence the annealing properties of the primers. Thus, a substantial number of strains can be classified as resistant on genetic analysis and as sensitive on phenotypic testing (Hristea et al., 2010). Specific mutations in rpoB could be associated with low-level rifampicin resistance that is not detectable by a routine susceptibility test performed on Löwenstein–Jensen medium with a rifampicin concentration of 40 μg mL–1 (Miotto et al., 2006). In conclusion, our results of MDR-TB underline the importance of strengthening classical case finding and treatment of smear-positive patients according to the ongoing Directly Observed Therapy-Short course (DOTS) program. The introduction of the rapid, specific, and technically affordable molecular techniques can be used and interpreted in conjunction with conventional methods to detect more active cases of MDR-TB cases.

The association of positive serological AMA in PBC patients with recurrent UTIs suggest a bacteria aetiology in PBC [7]. The hypothesis CDK activity that E. coli is a cause of PBC was first proposed in 1984, based on the higher prevalence of this bacterium in women in PBC when compared with age-matched women with other chronic liver diseases [13]. More recently, Varyani et al. reported that recurrent UTIs are present within 1 year prior to the diagnosis of in 29% of patients in PBC compared to 17% of non-PBC chronic liver disease controls [14]. This hypothesis is also supported by the

demonstration of T and B cell cross-reactivity between AMA epitopes and E. coli PDC-E2 sequences [24, 27, 41]. The induction of autoimmune

diseases is considered to Ivacaftor purchase be the result of complex interactions between genetic traits and environmental factors, including microbial infections [42]. The microbial aetiology of PBC is poorly defined and the pathogenic mechanisms of biliary injury in PBC remain largely unknown. Clues indicating a microbial aetiological component to the pathogenesis of PBC were based largely on experimental evidence of B and T cell cross-reactivity between the major mitochondrial autoantigens and their mimicking microbial antigenic epitopes [27, 29, 43-50]. Additional support comes from epidemiological studies, case reports or molecular evidence of the presence of microbial or viral agents in the liver or bile specimens of patients with PBC [13, 29, 50-52]. Several hypothetical mechanisms, such as bystander activation of autoreactive cells, induction of proinflammatory cytokines by microbial antigens and molecular mimicry between the microorganism and the host have been proposed to explain how microbes initiate autoimmunity [9-12]. Among these hypotheses, the theory of molecular mimicry has been addressed rigorously Unoprostone in PBC, which is based on the shared linear amino acid sequences or a conformational fit (for B cell cross-reactivity), or a motif (for T cell cross-reactivity) between a bacterial antigen and human ‘self’-antigen

[2, 28, 44, 53, 54]. An immune response directed against the mimicking microbial determinants may cross-react with the self-protein(s), and such autoreactivity may cause injury in targeted cells leading to cell destruction and, ultimately, autoimmune disease. In line with the theory of molecular mimicry, previously reported AMA cross-reactivity between the human PDC-E2 and its microbial counterparts in E. coli, N. aro and Lactobacillus delbrueckii suggested that PBC could be induced by exposure to these bacterial antigens [28, 42, 44, 55]. In addition, the identification of the 16S rRNA gene in livers from patients with PBC suggests that Propionibacterium acnes could be involved in granuloma formation in PBC [56].

In another study, a general inhibitor of all PKC isoforms was demonstrated to prevent peptide-mediated apoptosis in thymocytes 35. Additionally, the activation of nPKC was reported to promote a pathway for negative selection 36, 37. The significance of PKC proteins during clonal deletion is further

exemplified by findings showing the block in negative selection observed in Vav−/− mice can be rescued with PKC activation 35. Thus, the PKC family proteins are crucial prerequisites for negative selection. Activation of the PKC isozymes depends on the binding of phorbol ester tumor promoters or diacylglycerol (DAG) to the regulatory domain of the kinase. PMA is widely used as a PKC activator. However, PMA induces pleiotropic effects as it activates “non-kinase” proteins in addition to PKC isozymes HKI-272 purchase 38. To this end, potent PKC Selleckchem ITF2357 ligands have been synthesized based on the constrained structure of DAG. These DAG-lactones bind to the regulatory domain of PKCα with high affinity. However, the biological activity of these DAG-lactones in thymocytes has never been investigated 39–41. Here, we show that PKC and Ca2+ signals induced by the DAG-lactone HK434 and ionomycin, respectively, can induce the mitochondrial targeting of Nur77 and Nor-1 to promote

their association with Bcl-2. PKC is crucial for Nur77/Nor-1 mitochondrial targeting, apoptosis and exposure of the Bcl-2 BH3 domain in DP thymocytes. In TCR-stimulated thymocytes, slower migrating forms of Nur77 were seen at the mitochondria. These have been previously shown as heavily phosphorylated Nur77 42. We stimulated thymocytes with PMA/ionomycin in the presence of numerous kinase inhibitors, including LY294002 for Akt, GF109203X for PKC, SB202190 for p38, SP600125 for JNK and U0126 for the ERK1/2 pathways. We found that only with inhibition of the PKC family was Nur77′s translocation to the mitochondria greatly reduced (Fig. 1A). Inhibition of Akt, p38 or JNK had no effect or

even led to increased levels of Nur77 at the Aspartate mitochondria. In contrast to the requirement of the ERK1/2 pathway in DO11.10 T-cell hybridoma, Nur77 mitochondria localization was still seen in thymocytes treated with the ERK1/2 inhibitor U0126 (Fig. 1B). Even though reduced Nur77 phosphorylation by U0126 was evident, Nur77 could nevertheless be seen in the mitochondria fraction (Fig. 1B). No effects on the levels of nuclear Nur77 were seen with these inhibitors, including GF109203X, the PKC inhibitor. To show that the PKC family is indeed responsible for targeting Nur77 to the mitochondria, we used a specific PKC agonist, termed HK434 39. HK434 treatment alone could not induce expression of Nur77 (Fig. 1C). This is in line with work by our lab and other groups showing that treatment with the PKC activator, PMA alone, could not induce Nur77 protein levels in thymocytes or T-cell hybridomas 42, 43.

pneumoniae. As positive control, PMA at 200 ng/mL induced comparable concentrations of CRAMP. These results indicate that M. pneumoniae induces the release of CRAMP from neutrophils. The mechanisms of host defense against M. pneumoniae infection are not fully understood. In innate immunity against the infection, alveolar macrophages are considered to play a critical role in eliminating the microbes, whereas neutrophils recruited to the site of M. pneumoniae infection Adriamycin mouse may not be as effective as macrophages in their ability to kill mycoplasma (12, 17).

Interestingly, in some cases, mycoplasmas inhibit the activities of phagocytosis (18) and respiratory burst of neutrophils (19). It thus appears that neutrophils do not fully participate in protection against M. pneumoniae infection. On the basis of the findings of the present study, we would like to propose that neutrophils do play a protective role in infection with M. pneumoniae, because neutrophils recruited after M. pneumoniae infection secrete CRAMP into the bronchial lumens and this CRAMP inhibits the growth of the microbes. It is well known that macrophages are key players in the initiation of an innate immune response to M. pneumoniae

infection, and that they secrete cytokines such as IL-8 to recruit neutrophils to the site of infection (12, 20). We have previously reported that lipoproteins derived from M. pneumoniae stimulate macrophages to produce inflammatory cytokines such as IL-8 (15). Hence, during infection, recruited neutrophils in the bronchial lumens would probably have a moderate amount of CRAMP in their cytoplasm as Selleckchem Ivacaftor shown in Figure 4 and secrete that CRAMP into the extracellular milieu, which would result in killing Carteolol HCl of M. pneumoniae by CRAMP. It is of note that M. pneumoniae can be killed in the intracellular milieu, because we also detected M. pneumoniae in the cytoplasm of neutrophils containing CRAMP (data not shown). Such intracellular CRAMP is released from neutrophils treated with M. pneumoniae as shown in Figure 5. The mechanisms

underlying release of CRAMP are unknown and intriguing, since mycoplasma treatment of neutrophils has been reported to cause down-regulation of their activity (18, 19). To quantitate the concentrations of CRAMP in BALF, we developed a sandwich ELISA, in which rabbit anti-CRAMP Ab prepared in our laboratory was used. To our knowledge, there is no other ELISA kit for measuring CRAMP like our kit. As shown in Figure 2, CRAMP concentrations in BALF were 20–25 ng/mL, which may be much less than the concentration of 20 μg/mL that has been shown to exert anti-mycoplasmal activity in vitro. However, in vivo, the region in which interaction between microbes and antimicrobial peptides, including CRAMP, occurs may contain relatively higher concentrations of CRAMP. Alternatively, combinations of CRAMP and other antimicrobial peptides such as defensin may synergistically exert their killing activity against M. pneumoniae.

The phosphorylation of L-plastin relies on T-cell costimulation 8, 9, which selleckchem means it is dependent on signals from the TCR/CD3 receptor complex as well as from signals that origin from accessory receptor. The inhibition of L-plastin phosphorylation by dexamethasone could be

reverted by the synthetic steroid mifepristone, which shows a glucocorticoid receptor dependency 36. Thus, effects of dexamethasone on L-plastin phosphorylation are most likely due to gene expression, suggesting an interference with the signaling pathway upstream of L-plastin phosphorylation. It is known that dexamethasone inhibits proximal signals induced by TCR triggering 37–40. In addition, dexamethasone could interfere with CD28-mediated signals. PI3K activity was shown to be involved in CD28-mediated costimulation 41–43 selleck chemicals and its inhibition interferes with L-plastin phosphorylation in immune complex-stimulated

PMN 44. Dexamethasone inhibits PI3K in mast cells 45, which suggests PI3K and its inhibition might be involved in L-plastin phosphorylation upon T-cell costimulation. However, the relevance of dexamethasone for CD28-mediated PI3K activation in primary human T cells remains to be determined. One function of costimulation is the receptor movement to the immunological synapse 7, 12. Consequently, interference with L-plastin expression 5 or phosphorylation (this study) disturbed LFA-1 accumulation in the immune synapse. Interestingly, the effects on the accumulation of CD3 were much weaker and not significant in 5A-LPL-expressing T cells. It was therefore tempting to speculate that L-plastin phosphorylation Atorvastatin plays a role in peripheral SMAC, but not in central SMAC formation. The fact that 5E-LPL expression rescued only the LFA-1, but not the CD3 enrichment in dexamethasone-treated T cells strengthened that assumption. Interestingly, migration

of the TCR/CD3 complex toward the central SMAC depends on the actin cytoskeleton, as shown by the application of mycotoxins (e.g. cytochalasin D) 2. However, although 5A-LPL expression led to a lower F-actin content in stimulated T cells, the CD3 accumulation was not significantly disturbed. This might be due to the mode of inhibition of the actin cytoskeleton. Thus, in contrast to 5A-LPL expression, the application of mycotoxins to inhibit the actin cytoskeleton does not take into account the complex and spatio-temporal regulation of the actin cytoskeleton. In contrast to 5A-LPL expression, dexamethasone inhibits both the enrichment of the central SMAC-marker CD3 and the peripheral SMAC-marker LFA-1 in the immune synapse significantly. The difference between 5A-LPL expression and dexamethasone treatment on the CD3 enrichment in the immune synapse could be due to additional effects of dexamethasone on the actin cytoskeleton or signaling cascades.

Cytological examination of her post-operative cerebrospinal fluid revealed malignant cytology. The patient began craniospinal X-ray therapy. Three months following initial diagnosis, she died of disease. Post mortem examination of the brain and spinal cord revealed extensive spread along the subarachnoid space of the cerebellum, forebrain, brain stem and spinal cord. The term medulloblastoma describes a series of heterogeneous brain tumours originating in the cerebellum. This heterogeneity is reflected at two levels: (1) tumours Opaganib order are histopathologically and molecularly distinct; and (2) there is a lack of tight correlation between

histopathological and molecular subtypes, as tumours within each histopathological subtype are also molecularly heterogeneous. Accordingly,

SRT1720 additional genetic alterations, and analysis of the histopathological characteristics associated with them, may provide information for improving tumour subclassification. As a first step towards that purpose, we present three medulloblastoma cases with MLL2/3 mutations. Intriguingly, all three cases demonstrate features of a moderate to severe large-cell/anaplastic subtype (Figure 1B). However, despite these similarities, clinical outcomes varied. Patient 3 had both MLL2 and MLL3 mutations and, unlike the first two patients, had a poor clinical outcome. However, Patient 3 also had MYC amplification (frequently associated with a poor prognosis [5]). The role of MLL2/MLL3 complexes in medulloblastoma are unknown, yet genetic and biological evidence supports a tumour suppressor role [1-4, 6], and studies have identified MLL2/3 gene mutations in a variety of other cancers. MLL family genes are essential for histone modification and play roles in regulating other developmentally critical pathways [7, 8]. One of these pathways impacted by MLL2, retinoic acid signalling [9], may in turn impact orthodenticle homeobox

2 (OTX2) expression [10]. Because increased OTX2 expression was noted (Table 1, Figure 1C), it is tempting to postulate that MLL2/3 inactivation, and the subsequence changes in histone methylation, medroxyprogesterone may present a mechanism for OTX2 overexpression, and thus dysregulation of OTX2-associated pathways. Additionally, it is possible that loss of MLL2/MLL3 function impairs cell differentiation and renders cells susceptible to transformation. All cases presented here demonstrated anaplastic features, geographic necrosis and characteristics of the same histopathological subclass. Molecular subclassification, completed for cases 1 and 2, revealed Group 3 classification for both cases (classification based on Northcott et al. [11]). Because of the presence of MYC amplification and the extremely poor prognosis, it is likely that the tumour in case 3 is also a Group 3 tumour. It is expected that improved subclassification will provide guidance for therapy and risk assessment in the clinical setting.