Prognostic value of O-6-methylguanine-DNA methyltransferase (MGMT) protein expression in glioblastoma excluding nontumour cells from the analysis

AIMS

It is important to predict response to treatment with temozolomide (TMZ) in glioblastoma (GBM) patients. Both MGMT protein expression and MGMT promoter methylation status have been reported to predict the response to TMZ. We investigated the prognostic value of quantified MGMT protein levels in tumour cells and the prognostic importance of combining information of MGMT protein level and MGMT promoter methylation status.

METHODS

MGMT protein expression was quantified in tumour cells in 171 GBMs from the population-based Region of Southern Denmark (RSD)-cohort using a double immunofluorescence approach. Pyrosequencing was performed in 157 patients. For validation we used GBM-patients from a Nordic Study (NS) investigating the effect of radiotherapy and different TMZ schedules.

RESULTS

When divided at the median, patients with low expression of MGMT protein (AF-low) had the best prognosis (HR = 1.5, P = 0.01). Similar results were observed in the subgroup of patients receiving the Stupp regimen (HR = 2.0, P = 0.001). In the NS-cohort a trend towards superior survival (HR = 1.6, P = 0.08) was seen in patients with AF-low. Including MGMT promoter methylation status, we found for both cohorts that patients with methylated MGMT promoter and AF-low had the best outcome; median OS 23.1 and 20.0 months, respectively.

CONCLUSION

Our data indicate that MGMT protein expression in tumour cells has an independent prognostic significance. Exclusion of nontumour cells contributed to a more exact analysis of tumour-specific MGMT protein expression. This should be incorporated in future studies evaluating MGMT status before potential integration into clinical practice.

Combination therapy with interferon and JAK1-2 inhibitor is feasible: Proof of concept with rapid reduction in JAK2V617F-allele burden in polycythemia vera

We report a 55 year old woman with post-ET PV for 12 years, who experienced resolution of severe constitutional symptoms within 3 days, a marked reduction in splenomegaly and a rapid decline in the JAK2V617F allele burden during combination therapy with interferon-alpha2a and ruxolitinib. Within 4 weeks the patient achieved complete hematological remission with normalization of peripheral blood counts and within 10 months the JAK2V617F-allele burden was reduced from 90% to 28%. Such a rapid decline in the JAK2V617F allele burden is highly unusual in PV-patients during low-dose IFN-alpha2 monotherapy and this finding warrants a prospective study with combination therapy.

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Combination therapy with low-dose Interferon (IFN) and ruxolitinib (rux) is feasible.

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IFN and rux promptly alleviates symptoms and rapidly induces complete hematological remission.

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IFN and rux reduces allelic burden more effectively than seen in conventional IFN or rux regimens.

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The combinatorial approach was successful in a patient with prior side-effects to IFN.

Differentiation of foot-and-mouth disease virus infected animals from vaccinated animals using a blocking ELISA based on baculovirus expressed FMDV 3ABC antigen and a 3ABC monoclonal antibody

A blocking ELISA that differentiated foot-and-mouth disease virus (FMDV) infected animals from vaccinated animals was developed which uses baculovirus expressed FMDV 3ABC non-structural protein as antigen and monoclonal antibody against FMDV 3ABC non-structural protein as capture and detector antibody. Sera from naive, vaccinated and infected cattle, sheep and pigs were examined. The specificity of the test was high. Non-specific reactions observed in particular in sera of cattle and sheep could be removed by filtration and inactivation. Positive reactions were obtained for sera from cattle infected with all seven serotypes of FMDV. The test detected antibodies from days 7 or 9 following experimental infection of non-vaccinated cattle and sheep, and in cattle strong positive reactions persisted for up to 395 days after infection. In vaccinated cattle that became carriers after challenge with homologous FMDV, positive reactions were obtained in all but one case. In some of these cattle the antibody response was detected late in comparison to the non-vaccinated infected cattle. The test gave results that compared favourably with two commercial ELISA's when used to test sera from cattle, pigs and sheep collected after experimental or natural infection. The blocking ELISA based on recombinant FMDV 3ABC antigen and a monoclonal antibody to 3ABC is a promising tool for FMD control and eradication campaigns, where vaccination has been carried out.

Development of a novel quantitative real-time RT-PCR assay for the simultaneous detection of all serotypes of foot-and-mouth disease virus

Foot-and-mouth disease virus (FMDV) spreads extremely fast and the need for rapid and robust diagnostic virus detection systems was obvious during the recent European epidemic. Using a novel real-time RT-PCR system based on primer-probe energy transfer (PriProET) we present here an assay targeting the 3D gene of FMDV. The assay was validated for the efficacy to detect all known FMDV serotypes. The test method was linear over a range of at least 7 orders of magnitude and the detection limit was below the equivalent of 10 genomic copies. Analysing recent African probang samples the method was able to detect FMDV in materials from both cattle and buffalo. When compared to traditional virus cultivation the virus detection sensitivity was similar but the RT-PCR method can provide a laboratory result much faster than virus cultivation. The real-time PCR method confirms the identity of the amplicon by melting point analysis for added specificity and at the same time allows the detection of mutations in the probe region. As such, the described new method is suitable for the robust real-time detection of index cases caused by any serotype of FMDV.

Conservation and heterogeneity of the glutamate-rich protein (GLURP) among field isolates and laboratory lines of Plasmodium falciparum

Genetic variation of the glutamate-rich protein (GLURP) of Plasmodium falciparum was analysed in 29 field isolates and 15 laboratory lines of diverse geographical origin, by DNA sequencing of the non-repetitive 5'-region (R0) of the glurp gene. Polymorphism with respect to the length of the GLURP R2 repeat region was also analysed by a polymerase chain reaction method. As reference, the nucleotide sequence of the highly polymorphic 3'-region of the circumsporozoite protein gene was determined in the same isolates. It was found that even in the presence of variations in the GLURP R2 repeat region, immunodominant parts of the GLURP R0 region are surprisingly well conserved and the conservation is most pronounced in isolates from locations with very high malaria transmission. This might indicate that the R0 structure plays an important role in the parasite.