New biomarkers in glioma. PET/CT imaging and the prognostic value of somatostatin receptor subtype 2

Gliomas are brain tumors with dismal prognoses. They are classified based on histology and molecular biomarkers that guide therapeutic decision-making. Somatostatin receptor subtype 2- (SSTR2) targeted radionuclide therapy has been suggested as a novel treatment approach for gliomas. However, SSTR2 expression in different glioma entities is still controversial. Therefore, a method is needed for in vivo detection of SSTR2 in gliomas, which would help in the selection of patients for radionuclide therapy. Aims of this doctoral thesis were 1) to study the potential of positron emission tomography/computed tomography (PET/CT) to detect SSTR2 in gliomas in vivo, which would benefit the planning and follow-up of SSTR2-targeted radionuclide therapy, 2) to characterize SSTR2 expression in gliomas and explore its impact on survival, and 3) to evaluate serum glial fibrillary acidic protein (GFAP) and epidermal growth factor receptor (EGFR) as circulating biomarkers. First, animal glioma models were studied for SSTR2 expression with PET/CT, autoradiography, and immunohistochemistry. Secondly, a prospective clinical study was conducted to examine the value of SSTR2 PET/CT and serum GFAP and EGFR in 27 patients with malignant glioma. Thirdly, SSTR2 expression and its impact on survival was retrospectively evaluated in 184 patients with glioma. SSTR2 expression was detected in experimental gliomas, but the value of SSTR2-targeted PET/CT was limited. Also, in patients with malignant glioma, PET/CT could not predict SSTR2 expression in tumor tissue. In contrast, SSTR2 expression associated with oligodendrogliomas and improved prognoses, which was confirmed in the retrospective setup. Serum GFAP correlated with glioblastomas and tumor burden, whereas circulating EGFR was not related to tumor EGFR expression. In conclusion, SSTR2 and serum GFAP are potential new biomarkers with diagnostic, prognostic, and/or therapeutic value. SSTR2 PET/CT has limited value in selecting glioma patients for radionuclide therapy.Gliooman uudet biomarkkerit – somatostatiinireseptorien PET/TT -kuvantaminen ja vaikutus ennusteeseen Glioomat ovat pahanlaatuisia aivokasvaimia, joilla on taipumus uusiutua nopeasti. Kudosnäytteistä määritettävät molekyylipatologiset merkkiaineet ovat tärkeitä glioomien luokittelussa sekä ennusteen ja hoitovasteen arvioinnissa. Huonon ennusteen vuoksi glioomien uusia hoitomenetelmiä tutkitaan intensiivisesti. Tämän väitöskirjatyön tarkoituksena oli tutkia somatostatiinireseptorien (alatyyppi 2, SSTR2) ilmentymistä glioomissa sekä histologian että positroniemissiotomografia/tietokoneto-mografiakuvauksen (PET/TT) avulla. Taustalla oli ajatus SSTR2:een sitoutuvasta radiolääkkeestä, jota on ehdotettu uusiutuneiden pahanlaatuisten glioomien hoitomuodoksi. Hoidon edellytyksenä on, että kasvaimet ilmentävät SSTR2:a, johon sekä PET-merkkiaine että radiolääke pääsevät sitoutumaan. Lisäksi tavoitteena oli potilaiden verinäytteistä tutkia mahdollisia biomerkkiaineita (GFAP, glial fibrillary acidic protein sekä EGFR, epidermal growth factor receptor) glioomien luokittelua ja seurantaa varten. SSTR2:n ilmentymistä ja PET/TT-kuvantamista tutkittiin sekä kokeellisessa eläinmallissa että 27 potilaalla, jotka sairastivat pahanlaatuista glioomaa. Potilaiden verinäytteistä määritettiin lisäksi GFAP- sekä EGFR–pitoisuudet. Lopuksi SSTR2:n ilmentymistä tutkittiin retrospektiivisesti 184 glioomanäytteestä sekä ilmentymisen yhteyttä potilaan ennusteeseen. Kokeellinen gliooma ilmensi SSTR2:a, mutta PET/TT-kuvauksen hyöty tämän arvioimiseksi jäi alhaiseksi. Glioomapotilailla ei myöskään löytynyt yhteyttä kudosnäytteen SSTR2:n ilmenemisen ja PET-merkkiainekertymän välillä. Sen sijaan SSTR2:n ilmeneminen näytti liittyvän vahvasti aivokasvainten oligodendrogliaaliseen alatyyppiin sekä suotuisampaan ennusteeseen. Tämä yhteys vahvistettiin retrospektiivisessä työssä. Korkean seerumin GFAP-pitoisuuden todettiin lisäksi liittyvän aggressiivisiin glioblastoomiin sekä kasvaimen kokoon. Seerumin EGFR-pitoisuus sen sijaan ei liittynyt kasvainkudoksesta tehtyihin EGFR-määrityksiin. Tulokset viittaavat siihen, että SSTR2 ja seerumin GFAP voivat toimia sekä luokittelevina että ennusteellisina biomerkkiaineina glioomien hoidossa ja/tai seurannassa. PET/TT-kuvantamisella on kuitenkin vähäinen merkitys radiolääkehoidon arvioinnissa.Siirretty Doriast

The effect of tissue physiological variability on transurethral ultrasound therapy of the prostate

Therapeutic ultrasound is an investigational modality which could potentially be used for minimally invasive treatment of prostate cancer. Computational simulations were used to study the effect of natural physiological variations in tissue parameters on the efficacy of therapeutic ultrasound treatment in the prostate. The simulations were conducted on a clinical ultrasound therapy system using patient computed tomography (CT) data. The values of attenuation, perfusion, specific heat capacity and thermal conductivity were changed within their biological ranges to determine their effect on peak temperature and thermal dose volume. Increased attenuation was found to have the biggest effect on peak temperature with a 6.9% rise. The smallest effect was seen with perfusion with +-0.2% variation in peak temperature. Thermal dose was mostly affected by specific heat capacity which showed a 20.7% increase in volume with reduced heat capacity. Thermal conductivity had the smallest effect on thermal dose with up to 2.1% increase in the volume with reduced thermal conductivity. These results can be used to estimate the interpatient variation during the therapeutic ultrasound treatment of the prostate.Comment: Conference proceedin

Multiple formin proteins participate in glioblastoma migration

BackgroundThe prognosis of glioblastoma remains poor, related to its diffuse spread within the brain. There is an ongoing search for molecular regulators of this particularly invasive behavior. One approach is to look for actin regulating proteins that might be targeted by future anti-cancer therapy. The formin family of proteins orchestrates rearrangement of the actin cytoskeleton in multiple cellular processes. Recently, the formin proteins mDia1 and mDia2 were shown to be expressed in glioblastoma in vitro, and their function could be modified by small molecule agonists. This finding implies that the formins could be future therapeutic targets in glioblastoma.MethodsIn cell studies, we investigated the changes in expression of the 15 human formins in primary glioblastoma cells and commercially available glioblastoma cell lines during differentiation from spheroids to migrating cells using transcriptomic analysis and qRT-PCR. siRNA mediated knockdown of selected formins was performed to investigate whether their expression affects glioblastoma migration.Using immunohistochemistry, we studied the expression of two formins, FHOD1 and INF2, in tissue samples from 93 IDH-wildtype glioblastomas. Associated clinicopathological parameters and follow-up data were utilized to test whether formin expression correlates with survival or has prognostic value.ResultsWe found that multiple formins were upregulated during migration. Knockdown of individual formins mDia1, mDia2, FHOD1 and INF2 significantly reduced migration in most studied cell lines. Among the studied formins, knockdown of INF2 generated the greatest reduction in motility in vitro. Using immunohistochemistry, we demonstrated expression of formin proteins FHOD1 and INF2 in glioblastoma tissues. Importantly, we found that moderate/high expression of INF2 was associated with significantly impaired prognosis.ConclusionsFormins FHOD1 and INF2 participate in glioblastoma cell migration. Moderate/high expression of INF2 in glioblastoma tissue is associated with worse outcome. Taken together, our in vitro and tissue studies suggest a pivotal role for INF2 in glioblastoma. When specific inhibiting compounds become available, INF2 could be a target in the search for novel glioblastoma therapies.Peer reviewe

Radiomics and machine learning of multisequence multiparametric prostate MRI: Towards improved non-invasive prostate cancer characterization

Purpose To develop and validate a classifier system for prediction of prostate cancer (PCa) Gleason score (GS) using radiomics and texture features of T2-weighted imaging (T2w), diffusion weighted imaging (DWI) acquired using high b values, and T2-mapping (T2). Methods T2w, DWI (12 b values, 0–2000 s/mm2), and T2 data sets of 62 patients with histologically confirmed PCa were acquired at 3T using surface array coils. The DWI data sets were post-processed using monoexponential and kurtosis models, while T2w was standardized to a common scale. Local statistics and 8 different radiomics/texture descriptors were utilized at different configurations to extract a total of 7105 unique per-tumor features. Regularized logistic regression with implicit feature selection and leave pair out cross validation was used to discriminate tumors with 3+3 vs >3+3 GS. Results In total, 100 PCa lesions were analysed, of those 20 and 80 had GS of 3+3 and >3+3, respectively. The best model performance was obtained by selecting the top 1% features of T2w, ADCm and K with ROC AUC of 0.88 (95% CI of 0.82–0.95). Features from T2 mapping provided little added value. The most useful texture features were based on the gray-level co-occurrence matrix, Gabor transform, and Zernike moments. Conclusion Texture feature analysis of DWI, post-processed using monoexponential and kurtosis models, and T2w demonstrated good classification performance for GS of PCa. In multisequence setting, the optimal radiomics based texture extraction methods and parameters differed between different image types. </div

Validation of IMPROD biparametric MRI in men with clinically suspected prostate cancer: A prospective multi-institutional trial

Background: Magnetic resonance imaging (MRI) combined with targeted biopsy (TB) is increasingly used in men with clinically suspected prostate cancer (PCa), but the long acquisition times, high costs, and inter-center/reader variability of routine multiparametric prostate MRI limit its wider adoption.Methods and findings: The aim was to validate a previously developed unique MRI acquisition and reporting protocol, IMPROD biparametric MRI (bpMRI) (NCT01864135), in men with a clinical suspicion of PCa in a multi-institutional trial (NCT02241122). IMPROD bpMRI has average acquisition time of 15 minutes (no endorectal coil, no intravenous contrast use) and consists of T2-weighted imaging and 3 separate diffusion-weighed imaging acquisitions. Between February 1, 2015, and March 31, 2017, 364 men with a clinical suspicion of PCa were enrolled at 4 institutions in Finland. Men with an equivocal to high suspicion (IMPROD bpMRI Likert score 3-5) of PCa had 2 TBs of up to 2 lesions followed by a systematic biopsy (SB). Men with a low to very low suspicion (IMPROD bpMRI Likert score 1-2) had only SB. All data and protocols are freely available. The primary outcome of the trial was diagnostic accuracy-including overall accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value-of IMPROD bpMRI for clinically significant PCa (SPCa), which was defined as a Gleason score >= 3 + 4 (Gleason grade group 2 or higher). In total, 338 (338/364, 93%) prospectively enrolled men completed the trial. The accuracy and NPV of IMPROD bpMRI for SPCa were 70% (113/161) and 95% (71/75) (95% CI 87%-98%), respectively. Restricting the biopsy to men with equivocal to highly suspicious IMPROD bpMRI findings would have resulted in a 22% (75/338) reduction in the number of men undergoing biopsy while missing 4 (3%, 4/146) men with SPCa. The main limitation is uncertainty about the true PCa prevalence in the study cohort, since some of the men may have PCa despite having negative biopsy findings.Conclusions: IMPROD bpMRI demonstrated a high NPV for SPCa in men with a clinical suspicion of PCa in this prospective multi-institutional clinical trial.</p

Validation of IMPROD biparametric MRI in men with clinically suspected prostate cancer : A prospective multi-institutional trial

Background Magnetic resonance imaging (MRI) combined with targeted biopsy (TB) is increasingly used in men with clinically suspected prostate cancer (PCa), but the long acquisition times, high costs, and inter-center/reader variability of routine multiparametric prostate MRI limit its wider adoption. Methods and findings The aim was to validate a previously developed unique MRI acquisition and reporting protocol, IMPROD biparametric MRI (bpMRI) (NCT01864135), in men with a clinical suspicion of PCa in a multi-institutional trial (NCT02241122). IMPROD bpMRI has average acquisition time of 15 minutes (no endorectal coil, no intravenous contrast use) and consists of T2-weighted imaging and 3 separate diffusion-weighed imaging acquisitions. Between February 1, 2015, and March 31, 2017, 364 men with a clinical suspicion of PCa were enrolled at 4 institutions in Finland. Men with an equivocal to high suspicion (IMPROD bpMRI Likert score 3-5) of PCa had 2 TBs of up to 2 lesions followed by a systematic biopsy (SB). Men with a low to very low suspicion (IMPROD bpMRI Likert score 1-2) had only SB. All data and protocols are freely available. The primary outcome of the trial was diagnostic accuracy-including overall accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value-of IMPROD bpMRI for clinically significant PCa (SPCa), which was defined as a Gleason score >= 3 + 4 (Gleason grade group 2 or higher). In total, 338 (338/364, 93%) prospectively enrolled men completed the trial. The accuracy and NPV of IMPROD bpMRI for SPCa were 70% (113/161) and 95% (71/75) (95% CI 87%-98%), respectively. Restricting the biopsy to men with equivocal to highly suspicious IMPROD bpMRI findings would have resulted in a 22% (75/338) reduction in the number of men undergoing biopsy while missing 4 (3%, 4/146) men with SPCa. The main limitation is uncertainty about the true PCa prevalence in the study cohort, since some of the men may have PCa despite having negative biopsy findings. Conclusions IMPROD bpMRI demonstrated a high NPV for SPCa in men with a clinical suspicion of PCa in this prospective multi-institutional clinical trial.Peer reviewe

Radiomics and machine learning of multisequence multiparametric prostate MRI: Towards improved non-invasive prostate cancer characterization.

PurposeTo develop and validate a classifier system for prediction of prostate cancer (PCa) Gleason score (GS) using radiomics and texture features of T2-weighted imaging (T2w), diffusion weighted imaging (DWI) acquired using high b values, and T2-mapping (T2).MethodsT2w, DWI (12 b values, 0-2000 s/mm2), and T2 data sets of 62 patients with histologically confirmed PCa were acquired at 3T using surface array coils. The DWI data sets were post-processed using monoexponential and kurtosis models, while T2w was standardized to a common scale. Local statistics and 8 different radiomics/texture descriptors were utilized at different configurations to extract a total of 7105 unique per-tumor features. Regularized logistic regression with implicit feature selection and leave pair out cross validation was used to discriminate tumors with 3+3 vs >3+3 GS.ResultsIn total, 100 PCa lesions were analysed, of those 20 and 80 had GS of 3+3 and >3+3, respectively. The best model performance was obtained by selecting the top 1% features of T2w, ADCm and K with ROC AUC of 0.88 (95% CI of 0.82-0.95). Features from T2 mapping provided little added value. The most useful texture features were based on the gray-level co-occurrence matrix, Gabor transform, and Zernike moments.ConclusionTexture feature analysis of DWI, post-processed using monoexponential and kurtosis models, and T2w demonstrated good classification performance for GS of PCa. In multisequence setting, the optimal radiomics based texture extraction methods and parameters differed between different image types

Vascular adhesion protein-1 is actively involved in the development of inflammatory lesions in rat models of multiple sclerosis

Abstract Background Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial cell molecule and primary amine oxidase that mediates leukocyte entry to sites of inflammation. However, there is limited knowledge of the inflammation-related expression of VAP-1 in the central nervous system (CNS). Therefore, we investigated the expression of VAP-1 within the CNS vasculature in two focal rat models of experimental autoimmune encephalomyelitis (EAE) mimicking multiple sclerosis (MS). Methods EAE was induced either with Bacillus Calmette-Guérin, resulting in a delayed-type hypersensitivity-like pathogenesis (fDTH-EAE), or with myelin oligodendrocyte glycoprotein (fMOG-EAE). A subgroup of fMOG-EAE rats were treated daily with a selective VAP-1 inhibitor (LJP1586; 5 mg/kg). On 3 and 14 days after lesion activation, rat brains were assessed using magnetic resonance imaging (MRI), and ex vivo autoradiography was conducted to evaluate the binding of Gallium-68-labelled VAP-1 ligand. Histology and immunohistochemistry (OX-42, VAP-1, intercellular adhesion protein-1 [ICAM-1], P-selectin) supported the ex vivo autoradiography. Results EAE lesions showed MRI-detectable signal changes and binding of the VAP-1-targeting radiotracer in both rat models. Some of the VAP-1 positive vessels showed morphological features typical for high endothelial-like venules at sites of inflammation. Inhibition of VAP-1 activity with small molecule inhibitor, LJP1586, decreased lymphocyte density in the acute inflammatory phase of fMOG-EAE lesions (day 3, P = 0.026 vs. untreated), but not in the remission phase (day 14, P = 0.70 vs. untreated), and had no effect on the amount of OX-42-positive cells in either phase. LJP1586 treatment reduced VAP-1 and ICAM-1 expression in the acute inflammatory phase, whereas P-selectin remained not detectable at all studied stages of the disease. Conclusions Our results revealed that VAP-1 is expressed and functionally active in vasculature within the induced focal EAE lesions during the acute phase of inflammation and remains expressed after the acute inflammation has subsided. The study indicates that VAP-1 is actively involved in the development of inflammatory CNS lesions. During this process, the endothelial cell lesion-related vasculature seem to undergo a structural transformation from regular flat-walled endothelium to HEV-like endothelium