Failure pattern following complete resection plus radiotherapy and temozolomide is at the resection margin in patients with glioblastoma

Glioblastomas (GBM) are highly motile cancers that invade through normal brain. In the absence of curative chemotherapy this invasion, beyond surgical and radiotherapy margins, to distant brain sites is thought to be an important cause of treatment failure. Paradoxically, studies analyzing failure patterns have consistently shown that the large majority of failures occur at the original tumor site. This conflict may be explained by the fact these cancers are often only sub-totally resected and radiotherapy and chemotherapies fail to control this significant local cancer burden. We analyzed the failure pattern in 20 consecutive patients with complete resection of the gadolinium-enhancing portion of GBM demonstrated on the immediate post-operative magnetic resonance study, and who underwent a radical course of radiotherapy and chemotherapy. We found that recurrences occurred only at the resection margin in 17 of 20 patients. Recurrences were exclusively distant in 2 of 20 patients and occurred at both the resection margin and a distant site in 1 of 20 cases. We found that even in cases of complete resection of the gadolinium-enhancing portion of GBM 85 % of recurrences are localized to the resection margin.     

Methylenetetrahydrofolate reductase polymorphism in advanced colorectal cancer: a novel genomic predictor of clinical response to fluoropyrimidine-based chemotherapy.

PURPOSE: Fluorouracil (5-FU) is widely used in the treatment of colorectal cancer. Methylenetetrahydrofolate reductase (MTHFR) could play an important role in the action of 5-FU, an inhibitor of thymidylate synthetase, by converting 5,10-methylenetetrahydrofolate, a substrate of thymidylate synthetase, to 5-methyltetrahydrofolate. A polymorphism in MTHFR (677 C-->T; A222V) reduces enzyme activity and presumably increases the level of 5,10-methylenetetrahydrofolate. This increase would be expected to correlate with an improved response to 5-FU. The aim of the present study was to investigate the association between the MTHFR polymorphism and response to 5-FU and other fluoropyrimidines in patients with metastatic colorectal cancer. EXPERIMENTAL DESIGN: Forty-three patients with metastatic colorectal adenocarcinoma were analyzed. All patients were treated with p.o. or i.v. fluoropyrimidine-based chemotherapy. A comprehensive chart examination was performed to determine tumor response rates. Genomic DNA was extracted from blood, and MTHFR genotypes were determined. RESULTS: At least one copy of the mutant valine allele was present in 26 patients (21 heterozygotes and 5 homozygotes). The remaining 17 patients carried only the alanine allele. Exploration of the relationship between MTHFR alleles and response rates revealed a statistically significant difference in the frequency of the valine allele among responders versus nonresponders (P = 0.0351). This observation was associated with an odds ratio of 2.86 (95% confidence interval 1.06-7.73) for a response in individuals with a valine allele. CONCLUSIONS: Our results show a link between the MTHFR polymorphism and tumor response to fluoropyrimidine-based chemotherapy and suggest that MTHFR genotyping may be of predictive benefit in selecting treatment regimens.     

Can slow waves in the electrocorticogram (ECoG) help localize epileptic foci?

In patients operated for medically refractory epilepsy, ECoGs are often performed to help further localize the epileptogenic focus. During the necessarily short recording, spikes may be rare or absent, or may be only a partial representation of the epileptic activity. The usefulness of background abnormality in localizing the focus in ECoGs was therefore determined. The relationships of MRI, CT, and pathological findings with ECoG background were also noted. The ECoGs of 40 patients were recorded. Delta activity was evaluated by spectral analysis. In 22 ECoGs, maximum delta activity coincided spatially with maximum spiking or was adjacent to it. The region of maximum delta activity rarely coincided with CT, MRI and pathological findings. Although the relationship between delta activity and spiking was much stronger than expected by chance, it may not be sufficient to allow the use of delta activity to localize a focus in individual cases.     

Characterization of intracellular aggregates using fluorescently-tagged polyglutamine-expanded androgen receptor

Spinal bulbar muscular atrophy (SBMA) is a classic CAG-repeat neurodegenerative disease. It is caused by expansion of a polyglutamine (polyGln) tract in the androgen receptor (AR). Recent evidence has indicated a potential role for nuclear and cytoplasmic inclusions in the pathogenesis of these diseases. We have used blue and green fluorescently-tagged AR to show that both wild-type (WT) and poly-Gln-expanded full-length AR can form aggregates and that aggregation is not related to cytotoxicity. Twenty to thirty-five percent of all cell types transfected into COS cells showed aggregation containing both amino- and carboxy-terminal fluorescent tags. The aggregates reacted with (F39.4.1), an anti-AR antibody and with IC2, an expanded polyGln tract antibody. Western analysis of protein extracts revealed little evidence of proteolysis although some cleavage of the fusion proteins was seen. The general caspase inhibitor, Z-DEVD-FMK, did not affect aggregation in either wild type or polyGln-expanded GFP-AR transfected cells. Surprisingly, addition of Mibolerone a synthetic androgen significantly decreased inclusion formation in both WT and polyGln-expanded AR-transfected cells. Overall, we show that both WT and polyGln expanded full-length AR are found in aggregates and that proteolysis is not a requirement for aggregation. Our results also suggest that toxicity is not related to intracellular aggregation of polyGln expanded AR.     

Benefit of re-operation and salvage therapies for recurrent glioblastoma multiforme: results from a single institution

The optimal management of recurrent glioblastoma (GBM) has yet to be determined. We aim to assess the benefits of re-operation and salvage therapies (chemotherapy and/or re-irradiation) for recurrent GBM and to identify prognostic factors associated with better survival. All patients who underwent surgery for GBM between January 2005 and December 2012 followed by adjuvant radiotherapy, and who developed GBM recurrence on imaging were included in this retrospective study. Univariate and multivariate analysis was performed using Cox models in order to identify factors associated with overall survival (OS). One hundred and eighty patients treated to a dose of 60 Gy were diagnosed with recurrent GBM. At a median follow-up time of 6.2 months, the median survival (MS) from time of recurrence was 6.6 months. Sixty-nine patients underwent repeat surgery for recurrence based on imaging. To establish the benefits of repeat surgery and salvage therapies, 68 patients who underwent repeat surgery were matched to patients who did not based on extent of initial resection and presence of subventricular zone involvement at recurrence. MS for patients who underwent re-operation was 9.6 months, compared to 5.3 months for patients who did not have repeat surgery (p?<?0.0001). Multivariate analysis in the matched pairs confirmed that repeat surgery with the addition of other salvage treatment can significantly affect patient outcome (HR 0.53). Re-operation with additional salvage therapies for recurrent GBM provides survival prolongation at the time of progression.     

Cloning and characterization of an androgen receptor N-terminal-interacting protein with ubiquitin-protein ligase activity

The androgen receptor (AR) N-terminal domain plays a critical role in androgen-responsive gene regulation. A novel AR N-terminal-interacting protein (ARNIP) was isolated using the yeast two-hybrid system and its interaction with amino acids 11-172 of the normal or corresponding region of the polyglutamine-expanded human AR confirmed by glutathione S-transferase pulldown assays. ARNIP cDNAs cloned from NSC-34 (mouse neuroblastoma/spinal cord) or PC-3 (human prostate adenocarcinoma) mRNA encoded highly homologous 30 kDa (261 amino acids) cysteine-rich proteins with a RING-H2 (C3H2C3 zinc finger) domain; this motif is highly conserved in predicted ARNIP-homologous proteins from several other species. Expression of the approximately 1.7 kb ARNIP mRNA was detected in various tissues by Northern blotting, but was highest in mouse testes, kidney and several neuronal cell lines. In addition, the human ARNIP protein was found to be encoded by nine exons spanning 32 kb on chromosome 4q21. In COS-1 cells, coexpression of ARNIP and AR did not affect AR ligand-binding kinetics, nor did ARNIP act as a coactivator or corepressor in transactivation assays. However, AR N-terminal:C-terminal interaction was reduced in the presence of ARNIP. Intriguingly, ARNIP, and in particular its RING-H2 domain, functioned as a ubiquitin-protein ligase in vitro in the presence of a specific ubiquitin-conjugating enzyme, Ubc4-1. Mutation of a single cysteine residue in the ARNIP RING-H2 domain (Cys145Ala) abolished this E3 ubiquitin ligase activity. Fluorescent protein tagging studies revealed that AR-ARNIP interaction was hormone-independent in COS-1 cells, and suggest that colocalization of both AR and ARNIP to the nucleus upon androgen addition may allow ARNIP to play a role in nuclear processes. Thus, identification of a novel AR-interacting protein with ubiquitin ligase activity will stimulate further investigation into the role of ubiquitination and the ubiquitin-proteasome system in AR-mediated cellular functions.