IDH1 p.R132H ctDNA and D-2-hydroxyglutarate as CSF biomarkers in patients with IDH-mutant gliomas

INTRODUCTION

We aimed to evaluate IDH1 p.R132H mutation and 2-hydroxyglutarate (2HG) in cerebrospinal fluid (CSF) as biomarkers for patients with IDH-mutant gliomas.

METHODS

CSF was collected from patients with infiltrating glioma, and 2HG levels were measured by liquid chromatography-mass spectrometry. IDH1 p.R132H mutant allele frequency (MAF) in CSF-ctDNA was measured by digital droplet PCR (ddPCR). Tumor volume was measured from standard-of-care magnetic resonance images.

RESULTS

The study included 48 patients, 6 with IDH-mutant and 42 with IDH-wildtype gliomas, and 57 samples, 9 from the patients with IDH-mutant and 48 from the patients with IDH-wildtype gliomas. ctDNA was detected in 7 of the 9 samples from patients with IDH-mutant glioma, and IDH1 p.R132H mutation was detected in 5 of the 7 samples. The MAF ranged from 0.3 to 39.95%. Total 2HG level, D-2HG level, and D/L-2HG ratio in CSF were significantly higher in patients with IDH-mutant gliomas than in patients with IDH-wildtype gliomas. D-2HG level and D/L-2HG ratio correlated with total tumor volume in patients with IDH-mutant gliomas but not in patients with IDH-wildtype gliomas.

CONCLUSION

Our results suggest that detection of IDH1 p.R132H mutation by ddPCR and increased D-2HG level in CSF may help identify IDH-mutant gliomas. Our results also suggest that D-2HG level and D/L-2HG ratio correlate with tumor volume in patients with IDH-mutant gliomas. Further prospective studies with larger cohorts are needed to validate these findings.

Abstract 2417: Elucidating the role of SMARCB1 in bladder cancer progression and metastasis

Bladder cancer (BLCA) is the second most common urological malignancy in the US and is usually not curable at an advanced stage. The transcriptomic profiling data of bladder cancer revealed that 64% of BLCA patients have frequent dysregulation of the components of the SWI/SNF, a chromatin remodeling complex. Alterations in chromatin remodeling genes have been previously implicated in human oncogenesis. SMARCB1/INI1 is one of the critical core components of the SWI/SNF complex. In this study, we demonstrate that primary BLCA patients harboring SMARCB1 loss strongly associate with worse survival. Specifically, the biallelic inactivation of the SMARCB1 (SMARCB1 knockout (KO)) in BLCA cell lines resulted in the emergence of aggressive tumor growth leading to soft tissue metastasis to lungs, liver, kidney, and intestine in vivo. Mechanistic studies revealed that IL-6- STAT3 axis is upregulated in SMARCB1 KO BLCA cells. Our data suggest that the STAT3 specific inhibitor, inhibits invasive potential of SMARCB1 KO cells suggesting potential therapeutic efficacy for STAT3 inhibitor to treat subsets of BLCA harboring SMARCB1 loss. In addition, we identified a unique transcriptional signature activated upon SMARCB1 loss, which is predictive of poor patient outcome in BLCA, and hence may be clinically valuable. Bladder cancer (BLCA) is the second most common urological malignancy in the US and is usually not curable at an advanced stage. The transcriptomic profiling data of bladder cancer revealed that 64% of BLCA patients have frequent dysregulation of the components of the SWI/SNF, a chromatin remodeling complex. Alterations in chromatin remodeling genes have been previously implicated in human oncogenesis. SMARCB1/INI1 is one of the critical core components of the SWI/SNF complex. In this study, we demonstrate that primary BLCA patients harboring SMARCB1 loss strongly associate with worse survival. Specifically, the biallelic inactivation of the SMARCB1 (SMARCB1 knockout (KO)) in BLCA cell lines resulted in the emergence of aggressive tumor growth leading to soft tissue metastasis to lungs, liver, kidney, and intestine in vivo. Mechanistic studies revealed that IL-6- STAT3 axis is upregulated in SMARCB1 KO BLCA cells. Our data suggest that the STAT3 specific inhibitor, inhibits invasive potential of SMARCB1 KO cells suggesting potential therapeutic efficacy for STAT3 inhibitor to treat subsets of BLCA harboring SMARCB1 loss. In addition, we identified a unique transcriptional signature activated upon SMARCB1 loss, which is predictive of poor patient outcome in BLCA, and hence may be clinically valuable.

Citation Format: Chandra Sekhar Amara, Karthik Reddy Reddy, Yuntao Yang, Badrajee Waduge Danthasinghe, Allison Bellman, Andrea B. Apollo, David J. Shih, Leomar Ballester, Pavlos Msaouel, Wenjin J. Zheng, Matthew J. Ellis, Seth P. Lerner, Arun Sreekumar, Shyam M. Kavuri, Nagireddy Putluri. Elucidating the role of SMARCB1 in bladder cancer progression and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2417.

Abstract 2379: Gender-specific metabolome in bladder cancer: Role of EPHX2 in bladder cancer

Bladder cancer (BLCA) is the fourth most common cancer diagnosed in American men. In the U.S., men are four times more likely to be diagnosed with bladder cancer than women. Our research group has previously identified alterations in xenobiotic metabolism in BLCA. In this study, using a metabolomics approach, we identified alterations in the arachidonic acid pathway in bladder tumors from male versus female patients. Included within this altered arachidonic acid pathway was downregulation of EPHX2, an enzyme that converts epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DiHETs). Consistent with this, levels of EETs were significantly elevated in bladder tumors derived from male versus female patients. Cox proportional hazard regression analysis further revealed that reduced expression of EPHX2 was significantly associated with poor clinical outcome across multiple publicly available datasets only in male BLCA patients but not in females. Mechanistic studies revealed that EPHX2 over-expression in male-derived BLCA cell line reduced cell growth in vitro and tumor growth in vivo. Overall, these studies nominate EPHX2 as a potential tumor suppressor in male patients with BLCA.

Citation Format: Mohammed Khurshidul Hassan, Roshan Borkar, Karthik Reddy Kami Reddy, Danthasinghe Waduge Badrajee Piyarathna, Chandra Shekar Amara, Allison Bellman, ChandraShekar R. Ambati, Vasanta Putluri, Abu Hena Mostafa Kamal, Roni J. Bollag, Martha K. Terris, Leomar Y. Ballester, Yair Lotan, Cristian Coarfa, Arun Sreekumar, Nagireddy Putluri. Gender-specific metabolome in bladder cancer: Role of EPHX2 in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2379.

Abstract 3771: Mitochondrial metabolism and racial disparity of bladder cancer

Potential differences and mechanism in metabolism among bladder cancer (BLCA) patients of diverse race or ethnicities remain largely unexplored. Even though the incidence rate of BLCA in African Americans (AA) is nearly half as that of European Americans (EA), but AA have the worst survival. We performed the transcriptomics and metabolomics profiling in ancestry verified patients from AA and EA BLCA and observed mitochondrial complex activities were uniquely enriched in AA tumors compared to EA tumors. In addition, in vitro assay demonstrated differences in mitochondrial complex protein and activity between AA and EA BLCA. We further confirmed the reprogramming of mitochondrial metabolism using in vitro 13C labeled tracers in both AA and EA BLCA. Integration of metabolomics and transcriptomics data reveals the enrichment of mTOR pathway in AA BLCA. Our findings indicate that an elevated mitochondrial oxphos activity through mTOR activation could be a factor for AA BLCA progression and provide the rationale to examine mitochondrial specific inhibitors along with mTOR inhibitors to target BLCA on subset of patients from the AA community.

Citation Format: Karthik Reddy Kami Reddy, Jun Hyoung Park, Roni J. Bollag, Allison Bellman, Martha Terris, Seth P. Lerner, Leomar Y. Ballester, Yair Lotan, Benny Abraham Kaipparettu, Nagireddy Putluri. Mitochondrial metabolism and racial disparity of bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3771.

TERT Immunohistochemistry Expression as a Surrogate of TERT Promoter Mutations in Infiltrating Gliomas

Introduction/Objective

Genomic alterations are critical for the diagnosis of infiltrating gliomas. Mutations in the telomerase reverse transcriptase promoter (TERTp) are sufficient for a diagnosis of glioblastoma in some cases, independent of histologic features. Although DNA sequencing is the preferred method for evaluating TERTp mutations, there are limitations with regards to turn-around-time, accessibility, and cost. In this study, we evaluated the efficacy of using TERT immunohistochemistry (IHC) as a surrogate marker for the identification of TERTp mutations in infiltrating gliomas.

Methods/Case Report

The study cohort consisted of 31 infiltrating gliomas diagnosed following the 2016 WHO classification of CNS tumors by a board-certified neuropathologist. Each case was evaluated by immunohistochemistry (anti-TERT monoclonal antibody) and with a targeted next-generation sequencing (NGS) panel. A systemic literature search was conducted to examine reports of TERT antibody as a surrogate marker of TERTp mutations. TERTp mutation detected by sequencing was considered the gold standard.

Results (if a Case Study enter NA)

TERT immunohistochemistry demonstrated a sensitivity of 61.1% and specificity of 69.2%. Cases were divided into IDH-WT and IDH-mutant infiltrating gliomas. Among the IDH-WT group, 84% contained the TERTp mutation with a sensitivity of 62.5% and specificity of 33.3% for the TERTp IHC. IDH-mutant gliomas showed a 16.2% TERTp mutation rate, and immunohistochemistry had a sensitivity of 50% and 80% specificity. The probability of TERT immunohistochemistry in diagnosing TERTp mutations exhibited a poor likelihood ratio for both the positive and negative test. Literature review included 5 studies with an overall sensitivity and specificity remaining consistently low (<80%), with 2 of these studies evaluating CNS related tumors giving rise to similar diagnostic performance.

Conclusion

TERT IHC has suboptimal sensitivity and specificity for identifying TERTp mutations in IDH-WT and IDH- mutant infiltrating gliomas.

The experience of pain and anxiety in rectal cancer patients during high-dose-rate brachytherapy

BACKGROUND

Pain and anxiety have been reported as primary concerns for patients with head-and-neck, gynecologic, and prostate cancers undergoing high dose rate (hdr) brachytherapy. However, almost no research has been published on the degree to which these symptoms are experienced by rectal cancer patients undergoing hdr brachytherapy. We conducted a pilot study examining the experiences of rectal cancer patients during hdr brachytherapy, specifically the intensity and trajectory of their anxiety and pain.

METHODS

Rectal cancer patients (n = 25) who received hdr brachytherapy treatment at a hospital in Montreal, Quebec, completed verbal analog scales for pain and anxiety at 4 time points over 4 treatment days.

RESULTS

On all 4 days, a subset of patients reported moderate-to-severe anxiety before applicator insertion. Pain increased significantly from the time patients were lying on the table to immediately after insertion of the applicator (p < 0.001). Insertion of the applicator appears to be the most painful part of the procedure, and although anxiety declined to below baseline after applicator removal, pain remained somewhat elevated. Some patients required conscious sedation; however, reports of moderate-to-severe pain were more frequent from patients who received pain medications than from patients who did not receive such medication (p < 0.05).

CONCLUSIONS

Most patients with rectal cancer tolerated hdr rectal brachytherapy well, although the procedure is stressful and painful for some. Insertion of the applicator was found to be the point of maximal pain, and medication was not always completely successful at alleviating the pain, suggesting that additional psychosocial interventions might be needed, with particular emphasis on the time of applicator insertion.

Effect of oral rotavirus/iscom vaccines on immune responses in gnotobiotic lambs

A comparison of the effect on the immune responses in gnotobiotic lambs was made between an iscom vaccine prepared from recombinant rotavirus VP6 protein, an inactivated rotavirus/iscom-matrix vaccine and a vaccine comprising inactivated rotavirus alone. All three vaccines induced immunological priming and some degree of protection was observed after a single oral dose. However, different immune responses were induced in response to a virulent infection. The group vaccinated with the rotavirus/iscom-matrix vaccine showed a Th2-like response characterised by rotavirus-specific antibodies and a down-regulation of IFNgamma in jejunal Peyer's patches. Both Th1-like and Th2-like immune responses were induced in the group receiving the VP6 vaccine as seen by significantly increased expressions of IFNgamma and IL-6 in the jejunal Peyer's patch together with an increased percentage of CD8+ T cells in the intestine and rotavirus-specific antibodies at mucosal surfaces. Iscom vaccines given orally have the ability to induce both Th1-like and Th2-like immune responses in a ruminant model.

Maternal antibodies protect immunoglobulin deficient neonatal mice from mouse hepatitis virus (MHV)-associated wasting syndrome

PROBLEM

Neonatal mice nursed by dams lacking immunoglobulins (Igs) may often suffer from lethal runting if raised under conventional conditions. The present study was performed in order to clarify a) the cause of the wasting syndrome and b) the protective role of antigen-specific milk antibodies.

METHOD

Ig-deficient mouse embryos in a conventional environment were embryo-transferred to specified pathogen free (SPF) dams. Neonatal growth, mortality, and health status of mice from both environments was recorded. Suspected presence of mouse hepatitis virus (MHV) was tested by RT-PCR. Protective effects on neonatal mortality of milk containing different titers of anti-MHV antibodies were investigated in cross-fostering experiments.

RESULTS

The SPF colony of Ig-deficient mice exhibited no breeding problems, whereas Ig-deficient neonates in the conventional environment suffered from lethal wasting syndrome. Serological screening of the mice kept in the two environments revealed that mice in the conventional room had high titers of antibodies against mouse hepatitis virus. Presence of MHV in runting neonates was confirmed by pathological examinations and RT-nested-PCR using MHV genome specific primers. Milk containing high titers of anti-MHV antibodies, when provided for 8 days or more, completely prevented Ig-deficient neonates from developing wasting syndrome in the conventional environment.

CONCLUSION

These findings show that the neonatal wasting syndrome is associated with the presence of MHV and that neonates are efficiently protected by MHV-specific antibodies in the milk.