NIMG-39. UTILITY OF PHYSIOLOGIC MR METRICS IN DISTINGUISHING TRUE-PROGRESSION FROM PSEUDOPROGRESSION IN GLIOBLASTOMAS STRATIFIED BY MGMT PROMOTER METHYLATION

BACKGROUND

Methylation of O6-methyl-guanine-methyl transferase MGMT gene promoter is associated with favorable prognosis in glioblastoma (GBM) patients treated with surgery and chemoradiation therapy (CRT).

OBJECTIVE

To investigate potential of diffusion and perfusion MR imaging in distinguishing TP from PsP in GBM patients stratified by MGMT status.

METHODS

A cohort of 92 patients demonstrating new/increasing enhancing lesions within six months of completion of CRT underwent 3T MR imaging. Median values of mean diffusivity (MD), fractional anisotropy (FA), anisotropy coefficients [linear(CL), planar (CP), and spherical (CS)] and maximum relative cerebral blood volume (rCBVmax) were computed from enhancing lesions. Patients were classified as TP (n=65) and PsP (n=27) based on histopathology or follow-up MRI scans. Mann-Whitney, independent-sample T-tests and receiver operating characteristic (ROC) curve analyses were performed to distinguish TP from PsP. Of 92 patients, MGMT status was available from 60 patients [MGMT-methylated (n=23) and MGMT-unmethylated (n=37)]. Statistical analyses were also performed in distinguishing TP (n=15) and PsP (n=8) from MGMT-methylated and MGMT-unmethylated subgroups (TP=28; PsP=9). A p-value of 0.05 was considered significant.

RESULTS

Significantly higher rCBVmax and FA and a trend towards higher CP were observed in TP compared to PsP. Among these parameters, rCBVmax had the best sensitivity=62%, specificity=68% and accuracy=67% in distinguishing TP from PsP. ROC analysis revealed sensitivity=54%, specificity=78% and accuracy=68% after combination of these parameters. In MGMT methylated patients, only rCBVmax was significantly higher in TP than in PsP with sensitivity=79%, specificity=67% and accuracy=74% at a threshold rCBVmax value of 2.23. In MGMT unmethylated group, a trend towards higher rCBVmax was observed in TP than in PsP with sensitivity=67%, specificity=77%, accuracy=69%, threshold value=2.89.

CONCLUSION

Physiologic imaging parameters demonstrate variable diagnostic values for detecting PsP in GBM patients stratified by MGMT status. The best parameter in distinguishing TP from PsP was rCBVmax in patients demonstrating MGMT promoter methylation.

PATH-25. EXPERIENCE WITH AN RNA FUSION TRANSCRIPT PANEL FOR DETECTION OF POTENTIAL THERAPEUTIC TARGETS IN GLIOMAS

Next-generation sequencing to identify fusion proteins is increasingly employed across oncology to identify therapeutic targets.1 The clinical relevance of detecting fusion transcripts is well described in the pediatric glioma population, but similar reports for adult patients are scant.2 The University of Pennsylvania Health System (UPHS) has implemented routine use of an RNA fusion transcript panel (ArcherDX, Boulder, CO) on resected brain tumors since August 2017. Here we report the results of this analysis for adult patients with gliomas and highlight potentially targetable fusions. Over the period of August 2017 through December 2019, fusion analysis was performed on resected gliomas of over 200 patients. Ninety-seven patients were found to have a detected fusion protein. Eighty-three of the 97 patients (86%) had glioblastoma and 14 (14%) had lower grade gliomas. A total of 26 unique fusions were found. The most common (n=55) was EGFRvIII. NTRK fusions were of special interest as FDA-approved agents are available for patients harboring this genetic alteration.3 We identified 8 patients (8%) with NTRK fusions including ARHGEFF2:NTRK1, BNA: NTRK1, BCR: NTRK2, PDE5A/NTRK2, SKAP2/NTRK2, and STRN: NTRK2. Several of these patients went on to receive TRK kinase inhibitors with clinical benefit. Of the 97 patients with a detected fusion, 24 (25%) were found to have a potentially targetable fusion other than EGFRvIII, with inhibitors available in clinical trials or as off-label therapy. These fusions included BRAF (n=5; BRAF: LHFPL3, KIAA1549:BRAF), FGFR (n=9; FGFR3:BRAP, FGFR3:RENBP, FGFR3:TACC3), MET (n=7; CAPZA2-MET, KLF12:MET, PTPRZ1:MET, ST7:MET), and ROS1 (n=3; DLL: ROS1, GOPC: ROS1). In sum, routine clinical use of an RNA-based fusion transcript panel for adult patients with glioma may allow for detection of therapeutically targetable alterations in a meaningful proportion of cases. Prospective trials are needed to determine whether targeting specific fusions is beneficial for adult patients with glioma.

EPID-20. NOVEL GLIOBLASTOMA POPULATION-BASED HISTOLOGIC STAIN NORMALIZATION

Histopathologic evaluation has been an integral part of clinical diagnosis for central nervous system tumors, providing information essential for classification, management, and treatment of the disease. Hematoxylin and eosin (H&E) staining is routinely used in histology, providing detail of tissue morphology, structure, and cellular composition. MOTIVATION: Slide staining is rife with color intensity variations, mainly due to differences in materials and staining protocols among others. These variations introduce inaccuracies in downstream computational analysis and quantification of disease, disabling the generalization of computational models. To overcome these variations, current approaches arbitrarily select a slide within the cohort to normalize all slides of the cohort, leading to non-reproducible results in other cohorts. We develop a population-based whole slide image (WSI) normalization method based on overall region driven stain vectors and color histogram, weighted by corresponding percent contribution to overall slide (PCOS). METHODS: We identified a cohort of 509 H&E stained WSIs with corresponding anatomical annotations from the Ivy Glioblastoma Atlas Project. These WSIs and annotations were reviewed by two neuropathologists for correctly annotated regions. Each region was weighted according to PCOS, WSIs with PCOS < 0.05% were discarded. Then, the optical densities and histograms calculated. Resulting color histogram and optical density was applied to the WSI cohort. Finally, stain intensity variability pre- and post- normalization was compared. RESULTS: Normalizing WSIs based on our approach, results in a significant (p < 0.01, Wilcoxon) improvement in color intensity variation for eight of nine regions tested, with the exception of “Pseudopalisading Cells with no visible Necrosis” (p = 0.8). DISCUSSION: This novel transformative technique is insensitive to artificially staining background density and straightforward to apply. Furthermore, the approach shows promise towards a viable and robust tool for stain normalization in large WSIs cohorts, with the potential towards a stain normalization standard generalizable to other diseases.

NIMG-40. RADIOGENOMIC SIGNATURES OF DRIVER GENES IN NEWLY DIAGNOSED GLIOBLASTOMA PATIENTS BASED ON PRE-OPERATIVE MULTI-PARAMETRIC MRI

PURPOSE

Non-invasive and quantitative biomarkers of somatic mutations derived from multi-parametric MRI (MP-MRI) could potentially help in predicting the response of patients to therapy, leading to development of targeted and personalized treatments. In this study, we developed radiogenomic signatures of multiple driver genes using artificial intelligence (AI) methods.

METHODS

In this study, 2740 radiomic features, including shape and volumetric measures computed for different tumorous regions, and characteristics derived from histograms and gray-level co-occurrence matrix (GLCM), were extracted from pre-operative MP-MRI (T1, T1Gd, T2, T2-FLAIR, DTI, and DSC-MRI) scans of 161 patients with newly diagnosed glioblastoma. The tumor samples, collected surgically from these patients, were sequenced using an in-house targeted next generation sequencing (NGS) panel of genes. We constructed quantitative imaging signatures of somatic mutations in several genes from 161 IDH-wildtype glioblastoma patients, including ATRX, FGFR2, EGFR, MET, NF1, PDGFRA, PIK3CA, PTEN, RB1, TP53, using cross-validated SVM classifiers.

RESULTS

The cross-validated classification performance for each signature was assessed by area under the receiver operating characteristic (ROC) curve (AUC), indicating the following results: PTEN (n = 69, AUC = 0.64), EGFR (n = 52, AUC = 0.72), TP53 (n = 51, AUC = 0.67), NF1 (n = 33, AUC = 0.74), ATRX (n = 22; AUC = 0.74), FGFR2 (n = 6, AUC = 0.82), MET (n = 26, AUC = 0.77), PDGFRA (n = 14, AUC = 0.82), PIK3CA (n = 14, AUC = 0.78), RB1 (n = 14, AUC = 0.81).

CONCLUSION

Using multi-parametric MRI, we developed quantitative non-invasive in vivo signatures with the potential for pre-operative assessment of a glioblastoma’s molecular characteristics. These non-invasive radiogenomic biomarkers may be useful for understanding the molecular composition of a glioblastoma prior to surgical resection, thus enabling earlier selection of patients for targeted therapy trials and possible neoadjuvant treatment.

5,5-Diaryl-2-amino-4-pentenoates as novel, potent, and selective glycine transporter type-2 reuptake inhibitors

A novel series of 5,5-diaryl-2-amino-4-pentenoates was synthesized and found to be potent and selective glycine transporter type-2 reuptake inhibitors.

Allogeneic stem cell transplantation. An economic comparison of bone marrow, peripheral blood, and cord blood technologies

OBJECTIVES

To compare outcome attributes of three available technologies for stem cell transplantation--bone marrow transplantation (BM), peripheral blood cell transplantation (PB), and cord blood transplantation (CB). To compare the cost per recipient for the three technologies, incorporating all donor and antigen matching functions, as well as the transplantation procedures.

METHODS

Review of relevant literature using the CancerLit and HealthSTAR databases (plus earlier searches of MEDLINE and Embase) to summarize outcome differences. Estimations of cost per transplant using models drawing on Canadian experience.

RESULTS

The literature review indicated that PB may have a modest advantage over BM in terms of outcomes. The literature indicated that CB has longer engraftment times (although this may be due to inadequate controls). Our modeling exercise indicated that costs for PB and BM are similar. CB has a higher cost per recipient, due in large part to the higher testing costs for every donated unit.

CONCLUSIONS

Current literature is inadequate to provide an outcomes comparison of CB, PB, and BM. Viewed from a system-wide perspective, CB is a higher cost technique. However, PB and CB are emerging as technologies, and so our results should be viewed alongside the notion that there may be a steep learning curve in these technologies.

N1-(Benzenesulfonyl)tryptamines as novel 5-HT6 antagonists

N-Benzenesulfonyl-5-methoxy-N,N-dimethyltryptamine (BS/5-OMe DMT; 5) was shown to bind at human 5-HT6 serotonin receptors with high affinity (Ki = 2.3 nM) relative to serotonin (Ki = 78 nM). Structural variation failed to result in significantly enhanced affinity. BS/5-OMe DMT acts as an antagonist of 5-HT-stimulated adenylate cyclase (pA2 = 8.88 nM) and may represent the first member of a novel class of 5-HT6 antagonists.

5-Alkyltryptamine derivatives as highly selective and potent 5-HT1D receptor agonists

A series of 5-alkyltryptamines (6) and the corresponding conformationally constrained analogues (8) have been synthesized. The structure activity relationships (SAR) at the 5-position of the indole skeleton and the ethylamine side chain have been studied. Functional activities were assessed using isolated rabbit saphenous vein. Potent, selective ligands were found (6e, Ki 2.5 nM, 5-HT1B/5-HT1D 125-fold) that have potential for treating acute migraine.

6-Bicyclopiperazinyl-1-arylsulfonylindoles and 6-bicyclopiperidinyl-1-arylsulfonylindoles derivatives as novel, potent, and selective 5-HT6 receptor antagonists

A novel series of 6-bicyclopiperazinyl-1-arylsulfonylindoles and 6-bicyclopiperidinyl-1-arylsulfonylindoles derivatives was synthesized and found to be potent and selective 5-HT6 receptor antagonists.

Pyrrolo[3,2,1-ij]quinoline derivatives, a 5-HT2c receptor agonist with selectivity over the 5-HT2a receptor: potential therapeutic applications for epilepsy and obesity

A series of pyrrolo[3,2,1-ij]quinoline derivatives was synthesized, evaluated for their activity against the 5-HT2c and 5-HT2a, receptors and found to be agonists at 5-HT2c with selectivity over 5-HT2a.

Detection of neuron-specific protein gene product (PGP) 9.5 in the rat and zebrafish using anti-human PGP9.5 antibodies

Protein gene product (PGP) 9.5 is a developmentally regulated neuron- and neuroendocrine cell-specific ubiquitin carboxy-terminal hydrolase (UCHL1) expressed throughout the mammalian central and peripheral nervous systems. We have compared the use of monoclonal and polyclonal antibodies raised against human PGP9.5 for immunodetection of the protein in tissues of the zebrafish and rat. We show that a monoclonal antibody 13C4, which recognises an N-terminal epitope, detects PGP9.5 on Western blots as a single 27 kDa band present at high levels in zebrafish and rat brain. By contrast, the polyclonal antisera recognises multiple tissue-specific proteins in the rat and fails to detect PGP9.5 in the zebrafish. Finally, we have developed a specific ELISA assay for detection of cellular PGP9.5 using MAb13C4 and have employed the assay to show that PGP9.5 is not upregulated during nerve growth factor (NGF)-induced differentiation of rat PC12 cells.

Spatial and temporal genetic variation in British field populations of the grain aphid Sitobion avenae (F.) (Hemiptera: Aphididae) studied using RAPD-PCR

The grain aphid Sitobion avenae (F.) was collected from winter wheat and adjacent cocksfoot grass at two locations in southern England and at four times in the year (April-July). Genetic variation between individual aphids was then investigated using random amplified polymorphic DNA polymerase chain reaction. Individuals caught in wheat and cocksfoot during April provided very different and highly diagnostic banding patterns that were independent of location. This host-based genetic differentiability was less evident as the season progressed, largely as a result of genetic drift and local movement between adjacent host species, which appeared to be predominantely in the direction from cocksfoot to wheat. The diversity of putative clones fell significantly, the mean number of individuals per clone rose and clones became more exclusively associated with certain sites which suggests that long-distance migration may have less of a homogenizing effect than hitherto thought for this species.

Geographic and microgeographic genetic differentiation in two aphid species over southern England using the multilocus (GATA)4 probe

Samples of the grain aphid Sitobion avenae (F.) and the rose-grain aphid Metopolophium dirhodum (Walker) were collected in late March from wheat fields and adjacent road-side grasses at a number of locations in southern England. Unparasitized aphids were DNA fingerprinted using the multilocus (GATA)4 probe. Over all locations, the fingerprints of individual S. avenae caught in wheat had lower overall average distances of band migration (ADBM) and shared a higher proportion of bands, than fingerprints of individuals caught in adjacent road-side grasses. The ADBM of fingerprints of S. avenae collected on road-side grasses altered significantly with geographical location, while the ADBM of fingerprints of S. avenae caught on wheat did not. A comparison of the fingerprints of individual M. dirhodum caught in wheat and neighbouring road-side grasses did not reveal any genetic differentiation. Fingerprints of M. dirhodum that were caught in the same host type did however, show significant variation in ADBM between different locations. With both S. avenae and M. dirhodum, spatial autocorrelation revealed that locations that were close together were no more likely to have individuals with similar ADBM than locations that were far apart. Our results suggest that (i) particular clones of S. avenae prefer to colonize wheat, and/or that (ii) particular clones of S. avenae perform better on wheat than other clones. It is unclear why M. dirhodum did not show any genetic structuring according to host type, but this species appears to engage in sexual reproduction much more frequently than S. avenae in southern England.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of semirigid dressings on below-knee amputations

BACKGROUND AND PURPOSE

The effect of using semirigid dressings (SRDs) on the residual limb of individuals who have had below-knee amputations as a consequence of peripheral vascular disease was investigated, with the primary question being: Does the time to readiness for prosthetic fitting for patients treated with the SRDs differ from that of patients treated with soft dressings?

SUBJECTS

Forty patients entered the study and were alternately assigned to one of two groups. Nineteen patients were assigned to the SRD group, and 21 patients were assigned to the soft dressing group.

METHODS

The time from surgery to readiness for prosthetic fitting was recorded for each patient. Kaplan-Meier survival curves were generated for each group, and the results were analyzed with the log-rank test.

RESULTS

There was a difference between the two curves, and an examination of the curves suggests that the expected time to readiness for prosthetic fitting for patients treated with the SRDs would be less than half that of patients treated with soft dressings.

CONCLUSION AND DISCUSSION

The results suggest that a patient may be ready for prosthetic fitting sooner if treated with SRDs instead of soft dressings.

Evaluation of transgenic canola plants under field conditions

Eleven independent transgenic canola (Brassica napus ssp. oleifera L. cv. Westar and Regent) lines were evaluated in the field. The plants carried a neomycin phosphotransferase (NPTII) gene for kanamycin resistance that was introduced via Agrobacterium-mediated transformation. NPTII enzyme assays, Southern blot by hybridizations and progeny analysis, confirmed the stable, heritable integration and expression of the introduced NPTII gene. A number of agronomic characteristics evaluated under field conditions, including maturity yield, and oil and protein content, were all statistically comparable between the transformed and nontransforemd platns. These results indicate that canola can be genetically engineered successfully, and that the Agrobacterium-based transformation system employed does not induced any adverse effects on the intrinsic agronomic and qualitative traits critical to the agricultural industry.

Perinatal mortality in Southland: an ongoing review

A review of Southland's perinatal mortality was undertaken from 1978 to 1983 and included 124 deaths with a postmortem rate of 90%. The perinatal mortality rate has continued to fall during this period, and has more than halved since 1971. Prematurity remains the single most important factor, and there are still a large number of avoidable deaths. Eighty percent of confinements are attended solely by general practitioner obstetricians.

Cat satellite DNA. Isolation using netropsin with CsCl gradients

The absence of centromeric bands in the karyotype of Felis catus is confirmed. It is also confirmed that no satellite band is visible in CsCl density gradients. However, a satellite is observed both by recentrifuging the fraction of the DNA that bands at high density in CsCl and by using netropsin to enhance the resolution of a CsCl gradient containing total F. catus DNA. The satellite, about 0.5% of total DNA, was isolated by repeated centrifugation in CsCl alone and in CsCl with netropsin. Netropsin was removed and a pure satellite DNA obtained. The reassociation kinetics (C0t1/2 less than 10(-3) M . s) show that the satellite is of the simple sequence type and hence a candidate for centromeric heterochromatin. Its cytological localisation awaits in situ hybridisation experiments.

Granulomatous sarcoid nephropathy

When sarcoidosis of the renal parenchyma occurs it is rarely of major clinical significance. The clinical features and post-mortem findings of a case of subacute uraemic syndrome due to severe granulomatous involvement of the kidney by sarcoidosis are described. The case is unusual in that granulomatous sarcoid nephropathy resulted in death from renal failure within 4 months of onset of symptoms in the absence of clinically apparent sarcoidosis.

Lymphoma of the thyroid. An unusual clinical course in a patient possessing a 14/21 translocation

The unusual course of a lymphoma in a woman with a chromosome abnormality is reported. When aged 30 years, the right lobe of her thyroid gland was found to be infiltrated by a follicular lymphoma. Two years later, poorly differentiated diffuse lymphoctic lymphoma recurred locally, grew rapidly, and infiltrated the adjoining muscles. It was treated by widefield irradiation of the upper trunk and neck, and disappeared completely. The patient remained sympton-free for 22 years. Unequivocal Hodgkin's disease then developed in a left cervical lymph node; the patient received radiotherapy. Eighteen months later the right inguinal nodes were infiltrated by similar tumor and further treatment was given. Massive abdominal involvement followed and the patient died 28 years after developing the thyroid lymphoma. The tumor at necropsy was pleomorphic and contained Reed-Sternberg cells. The significance of the constitutional chromosome abnormality, a Robertsonian translocation of the No. 14 chromosome, is discussed.

Bile acids in the rat: studies in experimental occlusion of the bile duct

Bile acids in the plasma, urine, and small intestine of adult male rats with occluded bile ducts have been studied using a method of high specificity for their determination. After bile duct ligation cholic acid rapidly accumulates in the plasma for 8 hr, remains high for a further 8 hr, and subsequently diminishes; bile acids disappear from the small intestine. During the first 12 hr after bile duct ligation the excretion of trihydroxy acids in the urine was 10 times that of the dihydroxy acids. Subsequently the two excretion rates became equal. Because bile acids have been implicated in the etiology of hepatic damage following bile duct ligation, studies have been made of the effect on the liver of removing (with cholestyramine) and supplementing (with cholic acid) the intestinal bile acid pool. The addition of cholestyramine to the stock diet prevented the rise in trihydroxy bile acids after bile duct ligation, but did not prevent the development of histological abnormalities in the liver. Supplementing the diet with cholic acid raised the plasma cholic acid levels but had little effect on the hepatic histological findings.