Breast cancer malignancy is governed by regulation of the macroH2A2/TM4SF1 axis, the AKT/NF-κB pathway, and elevated MMP13 expression

The histone variant, macroH2A (mH2A) influences gene expression through epigenetic regulation. Tumor suppressive function of mH2A isoforms has been reported in various cancer types, but few studies have investigated the functional role of mH2A2 in breast cancer pathophysiology. This study aimed to determine the significance of mH2A2 in breast cancer development and progression by exploring its downstream regulatory mechanisms. Knockdown of mH2A2 facilitated the migration and invasion of breast cancer cells, whereas its overexpression exhibited the opposite effect. In vivo experiments revealed that augmenting mH2A2 expression reduced tumor growth and lung metastasis. Microarray analysis showed that TM4SF1 emerged as a likely target linked to mH2A2 owing to its significant suppression in breast cancer cell lines where mH2A2 was overexpressed among the genes that exhibited over twofold upregulation upon mH2A2 knockdown. Suppressing TM4SF1 reduced the migration, invasion, tumor growth, and metastasis of breast cancer cells in vitro and in vivo. TM4SF1 depletion reversed the increased aggressiveness triggered by mH2A2 knockdown, suggesting a close interplay between mH2A2 and TM4SF1. Our findings also highlight the role of the mH2A2/TM4SF1 axis in activating the AKT/NF-κB pathway. Consequently, activated NF-κB signaling leads to increased expression and secretion of MMP13, a potent promoter of metastasis. In summary, we propose that the orchestrated regulation of the mH2A2/TM4SF1 axis in conjunction with the AKT/NF-κB pathway and the subsequent elevation in MMP13 expression constitute pivotal factors governing the malignancy of breast cancer.

Characterization of 3D Organotypic Culture of Mouse Adipose-Derived Stem Cells

Although stem cells are a promising avenue for harnessing the potential of adipose tissue, conventional two-dimensional (2D) culture methods have limitations. This study explored the use of three-dimensional (3D) cultures to preserve the regenerative potential of adipose-derived stem cells (ADSCs) and investigated their cellular properties. Flow cytometric analysis revealed significant variations in surface marker expressions between the two culture conditions. While 2D cultures showed robust surface marker expressions, 3D cultures exhibited reduced levels of CD44, CD90.2, and CD105. Adipogenic differentiation in 3D organotypic ADSCs faced challenges, with decreased organoid size and limited activation of adipogenesis-related genes. Key adipocyte markers, such as lipoprotein lipase (LPL) and adipoQ, were undetectable in 3D-cultured ADSCs, unlike positive controls in 2D-cultured mesenchymal stem cells (MSCs). Surprisingly, 3D-cultured ADSCs underwent mesenchymal-epithelial transition (MET), evidenced by increased E-cadherin and EpCAM expression and decreased mesenchymal markers. This study highlights successful ADSC organoid formation, notable MSC phenotype changes in 3D culture, adipogenic differentiation challenges, and a distinctive shift toward an epithelial-like state. These findings offer insights into the potential applications of 3D-cultured ADSCs in regenerative medicine, emphasizing the need for further exploration of underlying molecular mechanisms.

Inducing positive inotropy in human iPSC-derived cardiac muscle by gene editing-based activation of the cardiac α-myosin heavy chain

Human induced pluripotent stem cells and their differentiation into cardiac myocytes (hiPSC-CMs) provides a unique and valuable platform for studies of cardiac muscle structure-function. This includes studies centered on disease etiology, drug development, and for potential clinical applications in heart regeneration/repair. Ultimately, for these applications to achieve success, a thorough assessment and physiological advancement of the structure and function of hiPSC-CMs is required. HiPSC-CMs are well noted for their immature and sub-physiological cardiac muscle state, and this represents a major hurdle for the field. To address this roadblock, we have developed a hiPSC-CMs (β-MHC dominant) experimental platform focused on directed physiological enhancement of the sarcomere, the functional unit of cardiac muscle. We focus here on the myosin heavy chain (MyHC) protein isoform profile, the molecular motor of the heart, which is essential to cardiac physiological performance. We hypothesized that inducing increased expression of α-MyHC in β-MyHC dominant hiPSC-CMs would enhance contractile performance of hiPSC-CMs. To test this hypothesis, we used gene editing with an inducible α-MyHC expression cassette into isogeneic hiPSC-CMs, and separately by gene transfer, and then investigated the direct effects of increased α-MyHC expression on hiPSC-CMs contractility and relaxation function. Data show improved cardiac functional parameters in hiPSC-CMs induced with α-MyHC. Positive inotropy and relaxation was evident in comparison to β-MyHC dominant isogenic controls both at baseline and during pacing induced stress. This approach should facilitate studies of hiPSC-CMs disease modeling and drug screening, as well as advancing fundamental aspects of cardiac function parameters for the optimization of future cardiac regeneration, repair and re-muscularization applications.

Quantitative and qualitative mutational impact of ionizing radiation on normal cells

The comprehensive genomic impact of ionizing radiation (IR), a carcinogen, on healthy somatic cells remains unclear. Using large-scale whole-genome sequencing (WGS) of clones expanded from irradiated murine and human single cells, we revealed that IR induces a characteristic spectrum of short insertions or deletions (indels) and structural variations (SVs), including balanced inversions, translocations, composite SVs (deletion-insertion, deletion-inversion, and deletion-translocation composites), and complex genomic rearrangements (CGRs), including chromoplexy, chromothripsis, and SV by breakage-fusion-bridge cycles. Our findings suggest that 1 Gy IR exposure causes an average of 2.33 mutational events per Gb genome, comprising 2.15 indels, 0.17 SVs, and 0.01 CGRs, despite a high level of inter-cellular stochasticity. The mutational burden was dependent on total irradiation dose, regardless of dose rate or cell type. The findings were further validated in IR-induced secondary cancers and single cells without clonalization. Overall, our study highlights a comprehensive and clear picture of IR effects on normal mammalian genomes.

CT findings of inferior vena cava trauma according to the level of injury: a retrospective analysis of 19 cases in a single trauma centre

AIM

To analyse the clinicoradiological characteristics of traumatic inferior vena cava (IVC) injury level on preoperative computed tomography (CT).

MATERIALS AND METHODS

This retrospective study evaluated patients from a single trauma centre treated for traumatic IVC injury between January 2014 and January 2021. Data on demographics, mechanism of injury, Injury Severity Score, radiological findings on CT and angiography, IVC injury level in surgical findings, complications, and clinical outcomes were collected.

RESULTS

During the 8-year study period, 36 patients presented with traumatic IVC injury: 19 underwent preoperative CT with 17 (89%) blunt and two (11%) penetrating injuries. The most common primary CT sign was contour abnormality (53%, n=10), followed by intraluminal flap and active extravasation (21%, n=4). Among the secondary signs, hepatic laceration (53%, n=10) and retroperitoneal haemorrhage (53%, n=10) were the most common. Frequencies of primary and secondary signs were higher in the infrarenal and suprarenal than in the retrohepatic vena cava injuries. Diagnostic capability of preoperative CT for IVC injury differed according to the IVC level. The detection rate was the highest for an infrarenal vena cava injury at 100% (n=4), followed by that for a suprarenal, suprahepatic, and retrohepatic vena cava injuries at 75% (n=3), 43% (n=3), and 25% (n=1), respectively.

CONCLUSION

CT findings of traumatic IVC injuries may vary depending on the mechanism and anatomical site of injury. Familiarity with IVC injury imaging features may help in diagnosis and surgical treatment planning.

Low-Dose Ionizing Radiation-Crosslinking Immunoprecipitation (LDIR-CLIP) Identified Irradiation-Sensitive RNAs for RNA-Binding Protein HuR-Mediated Decay

Although ionizing radiation (IR) is widely used for therapeutic and research purposes, studies on low-dose ionizing radiation (LDIR) are limited compared with those on other IR approaches, such as high-dose gamma irradiation and ultraviolet irradiation. High-dose IR affects DNA damage response and nucleotide-protein crosslinking, among other processes; however, the molecular consequences of LDIR have been poorly investigated. Here, we developed a method to profile RNA species crosslinked to an RNA-binding protein, namely, human antigen R (HuR), using LDIR and high-throughput RNA sequencing. The RNA fragments isolated via LDIR-crosslinking and immunoprecipitation sequencing were crosslinked to HuR and protected from RNase-mediated digestion. Upon crosslinking HuR to target mRNAs such as PAX6, ZFP91, NR2F6, and CAND2, the transcripts degraded rapidly in human cell lines. Additionally, PAX6 and NR2F6 downregulation mediated the beneficial effects of LDIR on cell viability. Thus, our approach provides a method for investigating post-transcriptional gene regulation using LDIR.

College students' preferences for tobacco treatment: a discrete choice experiment

The purpose of this study was to elicit preferences for the 'format' and 'content' of tobacco treatment among college student smokers, using an online discrete choice experiment (DCE) survey. A DCE survey, supplemented with a think-aloud method, was conducted among 54 college students who smoked combustible cigarettes and/or e-cigarettes. Conditional logistic regression models were constructed to determine optimal profiles of treatment. Cutting down nicotine rather than quitting 'cold turkey' (P < 0.001) and two-way communication (P < 0.001) were viewed as the most critical attributes for the intervention 'format'; changing behaviors rather than social groups/peers (P < 0.001) and autonomy (P < 0.001) were viewed as the most critical attributes for the intervention 'content'. Some preferences varied based on smoking subgroups. Combustible cigarette users preferred interventions with a longer time commitment (P < 0.05) and without nicotine replacement therapies (NRTs) (P < 0.001). Think-aloud data supported the DCE findings and further revealed a strong desire for cutting down nicotine and keeping social groups/peers and misconceptions regarding NRTs. Our study findings can guide tobacco treatment tailored to college students. These treatments should be tailored to specific smoker subgroups.

Downregulation of complement factor H attenuates the stemness of MDA‑MB‑231 breast cancer cells via modulation of the ERK and p38 signaling pathways

The complement system is a powerful innate immune system deployed in the immediate response to pathogens and cancer cells. Complement factor H (CFH), one of the regulators involved in the complement cascade, can interrupt the death of target cells. Certain types of cancer, such as breast cancer, can adopt an aggressive phenotype, such as breast cancer stem cells (BCSCs), through enhancement of the defense system against complement attack by amplifying various complement regulators. However, little is known about the association between CFH and BCSCs. In the present study, the roles of CFH in the CSC characteristics and radioresistance of MDA-MB-231 human breast cancer cells were investigated. CFH knockdown in MDA-MB-231 cells decreased the viability of the cells upon complement cascade activation. Notably, CFH knockdown also decreased cell survival and suppressed mammosphere formation, cell migration and cell invasion by attenuating radioresistance. Additionally, CFH knockdown further enhanced irradiation-induced apoptosis through G2/M cell cycle arrest. It was also discovered that CFH knockdown attenuated the aggressive phenotypes of cancer cells by regulating CSC-associated gene expression. Finally, by microarray analysis, it was found that the expression of erythrocyte membrane protein band 4.1-like 3 (EPB41L3) was markedly increased following CFH knockdown. EPB41L3 inhibited ERK and activated the p38 MAPK signaling pathway. Taken together, these results indicated that CFH knockdown attenuated CSC properties and radioresistance in human breast cancer cells via controlling MAPK signaling and through upregulation of the tumor suppressor, EPB41L3.

The Role of Local Prostate and Metastasis-Directed Radiotherapy in the Treatment of Oligometastatic Prostate Cancer

PURPOSE/OBJECTIVE(S)

The local ablative therapy for oligometastatic disease (OMD) has the potential to delay further metastases and improve survival. However, it has not been fully elucidated how prostate primary radiotherapy (PPR) and metastasis-directed radiotherapy (MDR) affect prognosis in each different OMD scenario. Herein, we tried to provide efficacy and future perspectives for MDR in oligometastatic prostate cancer.

MATERIALS/METHODS

Patients diagnosed with prostate cancer between 2010 and 2019 and treated for OMD (≤5 active lesions), which occurred synchronously or metachronously, were included. All patients received MDR at all detected lesions (OMDRT). OMDRT which was performed as soon as OMD was detected was classified as early, and OMDRT for progressions after hormone therapy was classified as late. The primary endpoint was survival after OMDRT, and timing of progression after RT was also analyzed.

RESULTS

A total of 82 patients with oligometastatic prostate cancer received OMDRT. Among 36 patients with synchronous OMD, 58% received PPR at diagnosis, and 64% received early OMDRT. Among 46 patients with metachronous OMD, 80% received early OMDRT, and 28 received sequential OMDRT for repetitive OMD events. With a median follow-up of 32 months after OMDRT, 54 patients experienced progression and 5-year survival was 78%. Survival was highest in patients with synchronous OMD and early RT (5-year 86%), and 5-year survival of patients with metachronous OMD and early RT was significantly higher than those with late RT (78% vs. 44%, p = 0.003). Survival of patients with synchronous OMD and PPR was significantly higher than those without PPR or with metachronous OMD (5-year 90% vs. 66%, p = 0.030), by delaying progressions (17.9 vs. 7.0 months, p = 0.005).

CONCLUSION

Survival gain could be achieved through OMDRT in oligometastatic prostate cancer, especially in synchronous OMD status. Also, it was possible to improve the prognosis further when OMDRT was performed early and with PPR.

Patient-Specific Deep Learning Model for Clinical Target Volume Delineation on Daily CBCT of Breast Cancer Patients based on Intentional Deep Overfit Learning (IDOL) Framework

PURPOSE/OBJECTIVE(S)

Increasingly complex target volumes and the use of modern irradiation techniques emphasize the importance of daily image guidance more than ever. Significant progress has been made in adjuvant breast cancer radiotherapy (RT) and the need for optimized image guidance is growing. Furthermore, the position of the breast during RT after breast-conserving surgery is highly variable than expected. In this context, cone beam computed tomography (CBCT) is a very effective tool enabling prompt and accurate adaptive radiation therapy (ART). In this study, we aim to develop a deep learning (DL)-based algorithm to segment clinical target volume (CTV) from daily CBCT scans. Also, we validate the optimization of further learning when applying the Intentional Deep Overfit Learning (IDOL) framework.

MATERIALS/METHODS

A total of 240 different CBCT scans obtained from 100 breast cancer patients were used for this study. CTV was defined as whole breast plus margin in all patients. The workflow consists of two training stages: (1) training a novel 'generalized' DL model (Swin_UNETR) to identify and delineate breast CTV on CBCT scans using 90 breast cancer patient cases (2) applying an 'intentional overfitting' to the 'generalized' DL model to generate a 'patient-specific' model using the remaining 10 breast cancer patients. In this study, for the intentionally overfitting stage, we additionally trained with CBCT scans from the patient's 1st fraction to the 14th fractions cases. The results of the proposed method were compared quantitatively with the expert's contours on 1st-15th fractions CBCT scans using Dice Similarity Coefficient (DSC).

RESULTS

The average DSC between the 'generalized' DL model-based breast CTV contours and reference contours for the patient's 15th fraction was 0.9672. When implementing the IDOL framework with the CBCT scan obtained during the patient's 1st treatment, the average DSC was improved to 0.9809. When additional CBCT scans taken during each of the 1st to 6th fractions were used for training, the average DSC could be most effectively raised to 0.9835. The p-value comparison between the 'generalized' DL model and the 1st fraction was found to be 3.62E-04, while the comparison with the 6th fractions resulted in a p-value of 8.36E-05. The average time required for IDOL training using one CBCT scan and six CBCT scans was 107 seconds and 127 seconds, respectively.

CONCLUSION

In this study, we developed a patient-specific DL-based training algorithm to segment CTV in CBCT scans for breast cancer patients. The performance improvement was relatively significant and was confirmed that using continual DL with additional CBCT scans, which are taken every day, can be more accurate and efficient than drawing breast CTV using a general model. Our novel patient-specific model can be effectively applied to various ARTs by not only reducing labor and time but also increasing accuracy.

Comparison of Early Outcomes of Stereotactic Accelerated Partial Breast Irradiation vs. Volumetric Modulated Arc Therapy-Based FAST-FORWARD Whole Breast Irradiation for Breast Cancer

PURPOSE/OBJECTIVE(S)

Despite evidence supporting APBI from 8 published prospective randomized trials enrolling over 10,000 women, the uptake of APBI in clinical practice is surprisingly low. This is being exacerbated by a new, convenient, and safe shortened WBI schedule. Here, we report the dosimetric and early outcome analyses of the first >1000 patients treated at our institution since the first adoption of stereotactic APBI and the ultra-hypofractionated WBI regimen.

MATERIALS/METHODS

From 2016 to 2022, 801 women with breast cancers in the suitable or cautionary categories according to the ASTRO APBI consensus panel guidelines, received 30 Gy in 5 fractions (92%) either using a robotic stereotactic radiation system (83%) or stereotactic volumetric-based arc therapy (VMAT, 17%). Between 2020 and 2022, 468 women, who were not candidates for APBI and not undergoing any regional irradiation received 26 Gy in 5 fractions using VMAT to the whole breast with the addition of cardiac sparing technique in left-sided breast cancer patients. Tumor bed boosts were delivered in 99% of FF-WBI patients. We evaluated dose-volume histogram parameters for target volumes and organs-at-risk and radiation-related toxicities during RT or within 6 months after the end of RT.

RESULTS

Target volume coverage was acceptable in both groups, with mean 96% of the target volumes receiving 95% of the prescribed doses and 0 cm3 within target volumes exceeding 105% of the prescribed doses. S-APBI resulted in small, but statistically significant, reductions in the radiation dose delivered to the ipsilateral breast, contralateral breast, lungs, heart, and coronary artery compared with FF-WBI. Comparing WBI to APBI, the mean contralateral breast dose, ipsilateral lung V20 Gy, mean contralateral lung dose, and mean heart dose, were reduced by 89%, 78%, 73%, and 29%, respectively. With median follow-up periods of 32 months for s-APBI and 19 months for FF-WBI, acute toxicity was assessable in all patients. The risks of any grade acute toxicity were 21% for s-APBI and 25% for FF-WBI (p = .117). Among them, grade 2 rates were 1.3% in both groups and no severe toxicity has been reported.

CONCLUSION

We found s-APBI and VMAT-based FF WBI were associated with favorable dosimetric and acute toxicity profiles. However, considering significantly less irradiated volume in the breast, lungs, and heart, APBI with advanced available technique options should be considered over any WBI-based approach for patients at low risk for local recurrence.

Association of Single Nucleotide Polymorphisms in Transforming Growth Factor-β1 Pathway and Risk of Radiation Pneumonitis in Lung Cancer Patients Treated with Thoracic Radiation Therapy

PURPOSE/OBJECTIVE(S)

Several clinical and dosimetric parameters are known to be associated with radiation-induced lung toxicity, including radiation pneumonitis (RP). Also, single nucleotide polymorphisms (SNPs) of genes in TGF-β1 pathway have a notable association with the RP. However, studies on the predictive value of SNPs for RP are still limited. Herein, we tried to develop a novel integrated predictive model for severe RP in lung cancer patients.

MATERIALS/METHODS

A total of 59 patients who were treated with definitive or preoperative radiotherapy for primary lung cancer and had DNA samples were included. Potentially functional and tagging SNPs of TGF-β1 (rs1800469, rs1800471, rs1982073, and rs11466345), BMP2 (rs235768, rs3178250, rs1979855, and rs170986), and BMP4 (rs17563, rs4898820, and rs762642) were genotyped. Logistic regression was performed to build severe (grade ≥2) RP prediction models, and best subset selection algorithm with L0 and L2 regulations was used for variable selection. Only clinical/dosimetric variables were evaluated in model 1, and those variables as well as SNPs were included in model 2. Using beta coefficient obtained by the logistic regression, a scoring system was also developed.

RESULTS

With median follow-up of 39.7 months, severe RP occurred in 20.3% of patients. In model 1, age (>66) and PTV volume (≥300 cc) were significant factors (p = 0.016, OR 8.820 [95% CI, 1.730-63.800]; and p = 0.024, OR 7.440 [95% CI, 1.460-52.100], respectively). In model 2, the above two factors (p = 0.010, OR 16.200 [95% CI, 2.440-187.000] and p = 0.025, OR 10.100 [95% CI, 1.610-105.000]) and the AG/GG genotype in BMP2 rs1979855 were significant factors (p = 0.031, OR 7.260 [95% CI, 1.380-59.100]). The AUC was significantly higher in model 2 than in model 1 (0.822 vs. 0.741, p = 0.029). According to developed scoring system, patients with a score >2.8 are more likely to experience severe RP (AUC 0.829).

CONCLUSION

BMP2 rs1979855 could serve as a reliable biomarker for predicting RP while significantly improving predictive power compared to when only clinical factors were used.

Distribution and Failure Patterns of Primary Central Nervous System Lymphoma Related to Hippocampus

PURPOSE/OBJECTIVE(S)

Hippocampus (HC) injury by conventional whole brain radiotherapy (C-WBRT) contributes to the neurocognitive decline in primary central nervous system lymphoma (PCNSL). Hippocampal avoidance (HA-WBRT) could minimize neurocognitive impairment by reducing the radiation dose to HC. However, its feasibility in PCNSL has not been examined regarding the incidence of HC involvement and failures. In this retrospective study, we assessed the risk of hippocampal area involvement at diagnosis and after treatments in PCNSL patients.

MATERIALS/METHODS

We identified 278 immunocompetent PCNSL patients diagnosed between 2000 and 2020. After high dose methotrexate-based induction chemotherapy, patients were observed or given consolidation therapy including RT, cytarabine alone, or autologous stem cell transplantation (ASCT). HC was contoured on T1 MRI image and expanded with a 5mm margin, generating hippocampal avoidance region (HAR). The extent of initial and recurrent lesions was evaluated using pre-induction and post-consolidation T1 contrast-enhanced MRI images. HC failure was defined as recurrence or progression at HAR and those who progressed after induction were excluded. The median follow up was 38.7 months (3.1-239.4).

RESULTS

Of 278 patients diagnosed with PCNSL, 39.9% of them had initial lesions at HAR (Figure 1a). After induction therapy, 212 evaluable patients received following treatments: RT (n = 145, 68.4%) consisting of C-WBRT (n = 114), HA-WBRT (n = 23), and focal RT (n = 8), observation (n = 38, 17.9%), cytarabine only (24, 11.3%), and ASCT (n = 5, 2.4%). Intracranial failures occurred in 47.6% (n = 101) of patients, with 33.7% (n = 34) of them in HAR (Figure 1b). The multivariate analysis identified multifocal disease (HR 3.86, 95% CI 1.15-9.73, p = 0.004) as the only factor associated with the risk of HC failure. Those with unifocal lesion outside HAR showed the lowest HC failure rate, 7.0%, while the highest HC failure rate, 25.4% was observed in the subgroup with multifocal disease within HAR at diagnosis (Figure 2a). In the lowest risk group (unifocal lesion outside HAR, n = 66), C-WBRT was not significantly associated with HC failure (HR 0.57, CI 0.09-3.33, P = .572, Figure 2b) or intracranial failure (HR 0.88, CI 0.40-1.91, P = .748).

CONCLUSION

Our data suggest the HA-WBRT could be explored in patients whose lesion is unifocal and located outside HAR. For patients without initial HAR involvement, hippocampal including WBRT did not significantly change HC failure. Further prospective study will be warranted to assess the feasibility of HA-WBRT in the subgroup with low risk of HC failure.

A Photograph-Based Visualization and Prediction Framework for Radiation-Induced Dermatitis

PURPOSE/OBJECTIVE(S)

This study aimed to suggest a photograph-based prediction system for acute radiation-induced dermatitis (RID), which can be applied to notify patients about the risk of the development of skin discomfort during radiotherapy.

MATERIALS/METHODS

The proposed system compared the spatial dose distribution with the RID region using the following methods. Skin photographs of patients were taken using an RGB-depth camera to acquire the shape information of RID. The skin surface data measured from the camera was registered with the shape of the external body contour using an iterative closest point algorithm. Spatial dose distribution of skin was extracted from the external body contour to a depth of 2 mm and projected onto the plane of the skin photograph using a transformation matrix for skin depth data. To compare the spatial distribution of skin dose with the shape of RID, the region of RID in patients' skin was delineated on photographs into three toxicity symptoms referring to the CTCAE criteria grade 1 (skin redness), grade 2 (dry desquamation), and grade 3 (moist desquamation). The degree of overlap between the shape of each RID and skin dose distribution was evaluated using the dice similarity coefficient (DSC). Threshold doses for predicting RID occurrence were estimated by skin isodose lines with the highest DSC. The developed system was validated using data from 19 patients who received volumetric modulated arc therapy for head-neck cancer at a single institution.

RESULTS

Threshold doses for RID grades 1, 2, and 3 were estimated using 18, 18, and 2 individual RID labels delineated on skin photographs, respectively. Isodose lines with the highest DSC for RID grades 1, 2, and 3 were calculated as 26.0 Gy, 36.5 Gy, and 54.0 Gy, respectively. A strong overlap (average DSC > 0.6) was observed between isodose skin lines and the shape of RID labels in all RID grades.

CONCLUSION

Assessing the spatial information of skin dose can be helpful in predicting acute RID. The region of RID shows a strong similarity with the skin dose distribution in head-neck patients. Visualization of skin dose on the patient photograph is potent to patient education for preparing the cosmetic discomfort during radiotherapy, which may lead to the improvement of the patient satisfaction in treatment.

Evaluation of Radiation Sensitivity Differences in Mouse Liver Tumor Organoids Using CRISPR/Cas9-Mediated Gene Mutation

BACKGROUND

To assess the radiosensitivity of liver tumors harboring different genetic mutations, mouse liver tumors were generated in vivo through the hydrodynamic injection of clustered regularly interspaced short palindromic repeat/caspase 9 (CRISPR/Cas9) constructs encoding single-guide RNAs (sgRNAs) targeting Tp53, Pten, Nf1, Nf2, Tsc2, Cdkn2a, or Rb1.

METHODS

The plasmid vectors were delivered to the liver of adult C57BL/6 mice via hydrodynamic tail vein injection. The vectors were injected into 10 mice in each group. Organoids were generated from mouse liver tumors. The radiation response of the organoids was assessed using an ATP cell viability assay.

RESULTS

The mean survival period of mice injected with vectors targeting Nf2 (4.8 months) was lower than that of other mice. Hematoxylin and eosin staining, immunohistochemical (IHC) staining, and target sequencing analyses revealed that mouse liver tumors harbored the expected mutations. Tumor organoids were established from mouse liver tumors. Histological evaluation revealed marked morphological similarities between the mouse liver tumors and the generated tumor organoids. Moreover, IHC staining indicated that the parental tumor protein expression pattern was maintained in the organoids. The results of the ATP cell viability assay revealed that the tumor organoids with mutated Nf2 were more resistant to high-dose radiation than those with other gene mutations.

CONCLUSIONS

This study developed a radiation response assessment system for mouse tumors with mutant target genes using CRISPR/Cas9 and organoids. The Tp53 and Pten double mutation in combination with the Nf2 mutation increased the radiation resistance of tumors. The system used in this study can aid in elucidating the mechanism underlying differential intrinsic radiation sensitivity of individual tumors.

A New Approach to Quantify and Grade Radiation Dermatitis Using Deep-Learning Segmentation in Skin Photographs

AIMS

Objective evaluation of radiation dermatitis is important for analysing the correlation between the severity of radiation dermatitis and dose distribution in clinical practice and for reliable reporting in clinical trials. We developed a novel radiation dermatitis segmentation system based on convolutional neural networks (CNNs) to consistently evaluate radiation dermatitis.

MATERIALS AND METHODS

The radiation dermatitis segmentation system is designed to segment the radiation dermatitis occurrence area using skin photographs and skin-dose distribution. A CNN architecture with a dilated convolution layer and skip connection was designed to estimate the radiation dermatitis area. Seventy-three skin photographs obtained from patients undergoing radiotherapy were collected for training and testing. The ground truth of radiation dermatitis segmentation is manually delineated from the skin photograph by an experienced radiation oncologist and medical physicist. We converted the skin photographs to RGB (red-green-blue) and CIELAB (lightness (L^∗), red-green (a^∗) and blue-yellow (b^∗)) colour information and trained the network to segment faint and severe radiation dermatitis using three different input combinations: RGB, RGB + CIELAB (RGBLAB) and RGB + CIELAB + skin-dose distribution (RGBLAB_D). The proposed system was evaluated using the Dice similarity coefficient (DSC), sensitivity, specificity and normalised Matthews correlation coefficient (nMCC). A paired t-test was used to compare the results of different segmentation performances.

RESULTS

Optimal data composition was observed in the network trained for radiation dermatitis segmentation using skin photographs and skin-dose distribution. The average DSC, sensitivity, specificity and nMCC values of RGBLAB_D were 0.62, 0.61, 0.91 and 0.77, respectively, in faint radiation dermatitis, and 0.69, 0.78, 0.96 and 0.83, respectively, in severe radiation dermatitis.

CONCLUSION

Our study showed that CNN-based radiation dermatitis segmentation in skin photographs of patients undergoing radiotherapy can describe radiation dermatitis severity and pattern. Our study could aid in objectifying the radiation dermatitis grading and analysing the reliable correlation between dosimetric factors and the morphology of radiation dermatitis.

Genomic targets and selective inhibition of DNA methyltransferase isoforms

Background

DNA methylation in the human genome is established and maintained by DNA methyltransferases (DNMTs). DNMT isoforms show differential expression by cell lineage and during development, but much remains to be elucidated about their shared and unique genomic targets.

Results

We examined changes in the epigenome following overexpression of 13 DNMT isoforms in HEK293T cells. We observed increased methylation (Δβ > 0.2) at 43,405 CpG sites, with expression of DNMT3A2, DNMTΔ3B4 and DNMTΔ3B2 associated with the greatest impact. De novo methylation occurred primarily within open sea regions and at loci with intermediate methylation levels (β: 0.2–0.6). 53% of differentially methylated loci showed specificity towards a single DNMT subfamily, primarily DNMTΔ3B and DNMT3A and 39% towards a single isoform. These loci were significantly enriched for pathways related to neuronal development (DNMTΔ3B4), calcium homeostasis (DNMTΔ3B3) and ion transport (DNMT3L). Repetitive elements did not display differential sensitivity to overexpressed DNMTs, but hypermethylation of Alu elements was associated with their evolutionary age following overexpression of DNMT3A2, DNMT3B1, DNMT3B2 and DNMT3L. Differential methylation (Δβ > 0.1) was observed at 121 of the 353 loci associated with the Horvath ‘epigenetic clock’ model of ageing, with 51 showing isoform specificity, and was associated with reduction of epigenetic age by 5–15 years following overexpression of seven isoforms. Finally, we demonstrate the potential for dietary constituents to modify epigenetic marks through isoform-specific inhibition of methylation activity.

Conclusions

Our results provide insight into regions of the genome methylated uniquely by specific DNMT isoforms and demonstrate the potential for dietary intervention to modify the epigenome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01325-4.

Cluster Analysis of DSC MRI, Dynamic Contrast-Enhanced MRI, and DWI Parameters Associated with Prognosis in Patients with Glioblastoma after Removal of the Contrast-Enhancing Component: A Preliminary Study

BACKGROUND AND PURPOSE

No report has been published on the use of DSC MR imaging, DCE MR imaging, and DWI parameters in combination to create a prognostic prediction model in glioblastoma patients. The aim of this study was to develop a machine learning-based model to find preoperative multiparametric MR imaging parameters associated with prognosis in patients with glioblastoma. Normalized CBV, volume transfer constant, and ADC of the nonenhancing T2 high-signal-intensity lesions were evaluated using K-means clustering.

MATERIALS AND METHODS

A total of 142 patients with glioblastoma who underwent preoperative MR imaging and total resection were included in this retrospective study. From the normalized CBV, volume transfer constant, and ADC maps, the parametric data were sorted using the K-means clustering method. Patients were divided into training and test sets (ratio, 1:1), and the optimal number of clusters was determined using receiver operating characteristic analysis. Kaplan-Meier survival analysis and log-rank tests were performed to identify potential parametric predictors. A multivariate Cox proportional hazard model was conducted to adjust for clinical predictors.

RESULTS

The nonenhancing T2 high-signal-intensity lesions were divided into 6 clusters. The cluster (class 4) with the relatively low normalized CBV and volume transfer constant value and the lowest ADC values was most associated with predicting glioblastoma prognosis. The optimal cutoff of the class 4 volume fraction of nonenhancing T2 high-signal-intensity lesions predicting 1-year progression-free survival was 9.70%, below which the cutoff was associated with longer progression-free survival. Two Kaplan-Meier curves based on the cutoff value showed a statistically significant difference (P = .037). When we adjusted for all clinical predictors, the cluster with the relatively low normalized CBV and volume transfer constant values and the lowest ADC value was an independent prognostic marker (hazard ratio, 3.04; P = .048). The multivariate Cox proportional hazard model showed a concordance index of 0.699 for progression-free survival.

CONCLUSIONS

Our model showed that nonenhancing T2 high-signal-intensity lesions with the relatively low normalized CBV, low volume transfer constant values, and the lowest ADC values could serve as useful prognostic imaging markers for predicting survival outcomes in patients with glioblastoma.

Comparison of trans-radial access and femoral access in cardiogenic shock patient who had undergone primary percutaneous coronary intervention from SMART RESCUE trial

Introduction

Throughout the years of percutaneous coronary intervention (PCI), the debate regarding access route, whether it being trasns-radial or femoral, is an ongoing agenda yet to be solved. Recent guidelines suggest trans-radial approach as an option to be considered in acute coronary syndrome (ACS). However, data on cardiogenic shock patients undergoing PCI is relatively sparse.

Purpose

Compare the clinical implication of trans-radial and femoral approach in cardiogenic shock patients who had undergone PCI.

Method

Cardiogenic shock patients who had undergone PCI from January 2014 to December of 2018 were enrolled. Patients were divided according to their access route respectfully. Primary outcome was composite endpoints including all-cause death, re-admission due to heart failure, myocardial infarction (MI) and cerebrovascular accident.

Result

A total of 694 (572 via femoral approach, 122 via radial approach) cardiogenic shock patients who received PCI were enrolled. Mean age femoral and radial groups was 66.59±12.51 and 66.66±12.8 respectfully. Disease severity was higher for femoral patients compared to radial patients as represented by their LM involvement, mechanical organ support (extracorporeal membrane oxygenation, continuous renal replacement therapy, mechanical ventilation), left ventricular ejection fraction (LVEF) and vasoactive inotropic score. Cox regression analysis after adjusting for conventional risk factors showed that femoral route was a poor prognosticator with respect to composite endpoints (HR=2.059, 95% CI 1.249–3.397, p value = 0.005). Radial approach patients had higher survival probability compared to femoral approach patients (Figure 1).

Conclusion

Radial approach in cardiogenic shock patients who are in need for PCI with relatively less severe clinical condition could be a reasonable option for access route.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Inha University Hospital

Prognostic impact of plasma glucose on cardiogenic shock patients with or without diabetes ellitus: smart rescue trial

Background

Even though the presence of hyperglycemia has shown to affect the clinical outcome of cardiogenic shock patients, the extent of hyperglycemia and its association with prognosis have not been fully addressed in large population

Purpose

Investigate the clinical relationship between hyperglycemic status and in-hospital mortality in cardiogenic shock patients

Method

A total of 1,177 consecutive cardiogenic shock patients were enrolled from January 2014 to December of 2018 at 12 hospitals in South Korea. The primary outcome was in-hospital mortality. Patients were divided into four groups according to their initial plasma glucose level in each of diabetes patients (n=752) and non-diabetes patients (n=425); group 1 (≤8 mmol/L), group 2 (8–12 mmol/L), group 3 (12–16 mmol/L) and group 4 (≥16 mmol/L).

Results

The groups with higher admission plasma glucose were associated with lower systolic blood pressure and higher lactic acid level in both diabetic and non-diabetic patients. In-hospital mortality increased in groups with higher admission plasma glucose level in non-diabetic patients (group-1:24.2%, group-2: 28.6%, group-3: 38.1%, group-4: 49.0%, p&lt;0.01) whereas in diabetic patients, mortality and admission plasma glucose level showed no significant association (group-1: 45%, group-2: 35.4%, group-3: 33.3%, group-4: 43.1%, p=0.26). Even after Multivariate analysis, high plasma glucose was an independent predictor of in-hospital mortality in non-diabetic patients

Conclusion

In cardiogenic shock patients, plasma glucose obtained at admission was associated with in-hospital mortality in non-diabetic patients

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): Inha University hospital

Impact of obesity paradox between genders on in-hospital mortality in cardiogenic shock: a retrospective cohort study

Background

In a few studies, obesity was associated with better outcomes in patients with cardiogenic shock (CS). Although this phenomenon, the “obesity paradox”, reportedly manifests differently based on sex in other disease entities, it has not yet been investigated in CS patients.

Methods and results

1,227 patients with CS from The REtrospective and prospective observational Study to investigate Clinical oUtcomes and Efficacy of left ventricular assist device for Korean patients with cardiogenic shock (RESCUE) registry in Korea were analyzed. The study population was classified into obese and non-obese groups according to Asian-Pacific criteria (BMI &gt;25.0 kg/m2 for obese). Clinical impact of obesity on in-hospital mortality according to sex was analyzed using logistic regression analysis and restricted cubic spline curves. In-hospital mortality rate was significantly lower in obese men than non-obese men (34.2% vs. 24.1%, p=0.004) while the difference was not significant in women (37.3% vs. 35.8%, p=0.884). As a continuous variable, higher BMI showed a protective effect in men conversely, BMI was not associated with clinical outcomes in women. Comparing to normal-weight patients, obesity was associated with a decreased risk of in-hospital death in men (multivariable-adjusted OR 0.63, CI 0.43–0.92, p=0.016), not in women (multivariable-adjusted OR 0.94, 95% CI 0.55–1.61, p=0.828). Interaction P value for the association between BMI and sex was 0.023.

Conclusions

Obesity paradox exists and apparently occurs in men among CS patients. The differential effect of BMI on in-hospital mortality was observed according to sex.

Funding Acknowledgement

Type of funding sources: None.

Risk factors and clinical effects of late leaflet thrombosis after transcatheter aortic valve replacement

Background

As the indications for trans-catheter aortic valve replacement (TAVR) expand, it is expected that the number of TAVR patients would increase and the follow-up duration would be longer. It is known that the incidence of leaflet thrombosis is higher in TAVR than in surgical aortic valve replacement (SAVR), but not much is known about the risk factors of late leaflet thrombosis in TAVR.

Aim

Therefore, in this study, the incidence and risk factors of late leaflet thrombosis at late term after TAVR and the effect on clinical course of late leaflet thrombosis would be investigated.

Method

There were 176 patients undergone TAVR from January 2015 to October 2020 in one tertiary hospital of south korea. 94 patients had follow-up cardiovascular computed tomography (CT) between 3 months and 2 years after TAVR. Among 94 patients, late leaflet thrombosis was discovered at 20 patients, and risk factors were analyzed by comparing clinical factors, echocardiographic and cardiovascular CT information, and angiographic data between the group with and without late leaflet thrombosis. And the difference in aortic valve hemodynamics between the group with and without leaflet thrombosis was examined and clinical outcomes were compared. Clinical outcome was defined as the composite of all-cause death, stroke, heart failure (HF) admission, redo-aortic valve (AV) replacement and major bleeding after detection of late leaflet thrombosis.

Results

Indexed mean sinus of Valsalva diameter, AV calcium score and post procedure estimated orifice area (EOA) had predictability of late leaflet thrombosis with AUC value of 0.670 (95% CI [0.546–0.795], p value = 0.020), AUC value of 0.698 (95% CI [0.544–0.851], p value = 0.012) and AUC value of 0.665 (95 percent CI [0.548–0.782], p value = 0.031), respectively (Figure 1).

In echocardiography performed at the time of follow-up CT, AV max velocity and AV mean pressure gradient were higher in thrombosis group and EOA and Doppler velocity index were lower in thrombosis group than in no thrombosis group within normal range (Figure 2). Clinical outcome was not significant different between the two groups (log rank p value = 0.560).

Conclusion

Larger indexed sinus of Valsalva diameter, higher AV calcium score and smaller post procedure AV EOA were risk factors for late leaflet thrombosis after TAVR. Subclinical late leaflet thrombosis have a benign course when properly managed.

Funding Acknowledgement

Type of funding sources: None.

Deep Learning-Based Prediction of the 3D Postorthodontic Facial Changes

With the increase of the adult orthodontic population, there is a need for an accurate and evidence-based prediction of the posttreatment face in 3 dimensions (3D). The objectives of this study are 1) to develop a 3D postorthodontic face prediction method based on a deep learning network using the patient-specific factors and orthodontic treatment conditions and 2) to validate the accuracy and clinical usability of the proposed method. Paired sets (n = 268) of pretreatment (T1) and posttreatment (T2) cone-beam computed tomography (CBCT) of adult patients were trained with a conditional generative adversarial network to generate 3D posttreatment facial data based on the patient's gender, age, and the changes of upper (ΔU1) and lower incisor position (ΔL1) as input. The accuracy was calculated with prediction error and mean absolute distances between real T2 (T2) and predicted T2 (PT2) near 6 perioral landmark regions, as well as percentage of prediction error less than 2 mm using test sets (n = 44). For qualitative evaluation, an online survey was conducted with experienced orthodontists as panels (n = 56). Overall, PT2 indicated similar 3D changes to the T2 face, with the most apparent changes simulated in the perioral regions. The mean prediction error was 1.2 ± 1.01 mm with 80.8% accuracy. More than 50% of the experienced orthodontists were unable to distinguish between real and predicted images. In this study, we proposed a valid 3D postorthodontic face prediction method by applying a deep learning algorithm trained with CBCT data sets.

A cleavage-based surrogate reporter for the evaluation of CRISPR-Cas9 cleavage efficiency

CRISPR-Cas9 is a powerful tool for genome engineering, but its efficiency largely depends on guide RNA (gRNA). There are multiple methods available to evaluate the efficiency of gRNAs, including the T7E1 assay, surveyor nuclease assay, deep sequencing, and surrogate reporter systems. In the present study, we developed a cleavage-based surrogate that we have named the LacI-reporter to evaluate gRNA cleavage efficiency. The LacI repressor, under the control of the EF-1α promoter, represses luciferase or EGFP reporter expression by binding to the lac operator. Upon CRISPR-Cas9 cleavage at a target site located between the EF-1α promoter and the lacI gene, repressor expression is disrupted, thereby triggering luciferase or EGFP expression. Using this system, we can quantitate gRNA cleavage efficiency by assessing luciferase activity or EGFP expression. We found a strong positive correlation between the cleavage efficiency of gRNAs measured using this reporter and mutation frequency, measured using surveyor and deep sequencing. The genome-editing efficiency of gRNAs was validated in human liver organoids. Our LacI-reporter system provides a useful tool to select efficient gRNAs for genome editing.

Review: The development of the gastrointestinal tract microbiota and intervention in neonatal ruminants

The complex microbiome colonizing the gastrointestinal tract (GIT) of ruminants plays an important role in the development of the immune system, nutrient absorption and metabolism. Hence, understanding GIT microbiota colonization in neonatal ruminants has positive impacts on host health and productivity. Microbes rapidly colonize the GIT after birth and gradually develop into a complex microbial community, which allows the possibility of GIT microbiome manipulation to enhance newborn health and growth and perhaps induce lasting effects in adult ruminants. This paper reviews recent advances in understanding how host-microbiome interactions affect the GIT development and health of neonatal ruminants. Following initial GIT microbiome colonization, continuous exposure to host-specific microorganisms is necessary for GIT development and immune system maturation. Furthermore, the early GIT microbial community structure is significantly affected by early life events, such as maternal microbiota exposure, dietary changes, age and the addition of prebiotics, probiotics and synbiotics, supporting the idea of microbial programming in early life. However, the time window in which interventions can optimally improve production and reduce gastrointestinal disease as well as the role of key host-specific microbiota constituents and host immune regulation requires further study.

Longitudinal Imaging of Liver Cancer Using MicroCT and Nanoparticle Contrast Agents in CRISPR/Cas9-Induced Liver Cancer Mouse Model

Introduction:

Micro-computed tomography with nanoparticle contrast agents may be a suitable tool for monitoring the time course of the development and progression of tumors. Here, we suggest a practical and convenient experimental method for generating and longitudinally imaging murine liver cancer models.

Methods:

Liver cancer was induced in 6 experimental mice by injecting clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated protein 9 plasmids causing mutations in genes expressed by hepatocytes. Nanoparticle agents are captured by Kupffer cells and detected by micro-computed tomography, thereby enabling longitudinal imaging. A total of 9 mice were used for the experiment. Six mice were injected with both plasmids and contrast, 2 injected with contrast alone, and one not injected with either agent. Micro-computed tomography images were acquired every 2- up to 14-weeks after cancer induction.

Results:

Liver cancer was first detected by micro-computed tomography at 8 weeks. The mean value of hepatic parenchymal attenuation remained almost unchanged over time, although the standard deviation of attenuation, reflecting heterogeneous contrast enhancement of the hepatic parenchyma, increased slowly over time in all mice. Histopathologically, heterogeneous distribution and aggregation of Kupffer cells was more prominent in the experimental group than in the control group. Heterogeneous enhancement of hepatic parenchyma, which could cause image quality deterioration and image misinterpretation, was observed and could be due to variation in Kupffer cells distribution.

Conclusion:

Micro-computed tomography with nanoparticle contrast is useful in evaluating the induction and characteristics of liver cancer, determining appropriate size of liver cancer for testing, and confirming therapeutic response.

MGMT Promoter Methylation Status in Initial and Recurrent Glioblastoma: Correlation Study with DWI and DSC PWI Features

BACKGROUND AND PURPOSE

O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in primary and recurrent glioblastoma may change during treatment. The purpose of this study was to correlate MGMT promoter methylation status changes with DWI and DSC PWI features in patients with recurrent glioblastoma after standard treatment.

MATERIALS AND METHODS

Between January 2008 and November 2016, forty patients with histologically confirmed recurrent glioblastoma were enrolled. Patients were divided into 3 groups according to the MGMT promoter methylation status for the initial and recurrent tumors: 2 groups whose MGMT promoter methylation status remained, group methylated (n = 13) or group unmethylated (n = 18), and 1 group whose MGMT promoter methylation status changed from methylated to unmethylated (n = 9). Normalized ADC and normalized relative CBV values were obtained from both the enhancing and nonenhancing regions, from which histogram parameters were calculated. The ANOVA and the Kruskal-Wallis test followed by post hoc tests were performed to compare histogram parameters among the 3 groups. The t test and Mann-Whitney U test were used to compare parameters between group methylated and group methylated to unmethylated. Receiver operating characteristic curve analysis was used to measure the predictive performance of the normalized relative CBV values between the 2 groups.

RESULTS

Group methylated to unmethylated showed significantly higher means and 90th and 95th percentiles of the cumulative normalized relative CBV values of the nonenhancing region of the initial tumor than group methylated and group unmethylated (all P < .05). The mean normalized relative CBV value of the nonenhancing region of the initial tumor was the best predictor of methylation status change (P < .001), with a sensitivity of 77.78% and specificity of 92.31% at a cutoff value of 2.594.

CONCLUSIONS

MGMT promoter methylation status might change in recurrent glioblastoma after standard treatment. The normalized relative CBV values of the nonenhancing region at the first preoperative MR imaging were higher in the MGMT promoter methylation change group from methylation to unmethylation in recurrent glioblastoma.

Irisin promotes odontogenic differentiation and angiogenic potential in human dental pulp cells

AIM

To determine whether irisin, a newly discovered myokine that links exercise-induced and metabolic homeostasis, is able to promote odontogenic differentiation and angiogenesis in human dental pulp cells (HDPCs).

METHODOLOGY

Cell viability in the presence of irisin was measured. Real-time PCR and Western blot analysis were performed to evaluate the expression levels of irisin, odontogenic and angiogenic markers. The involvement of mitogen-activated protein kinase (MAPK) and the protein kinase B (Akt) signalling pathway was evaluated by Western blot. To evaluate mineralization nodule formation, alkaline phosphatase (ALP) staining and alizarin red S staining were performed. Scratch wound assays were performed to evaluate the effects of irisin on cell migration. The data were analysed using one-way analysis of variance (anova) followed by Tukey post hoc test and Student's t-test. Statistical significance was considered at P < 0.05.

RESULTS

Irisin significantly promoted odontogenic differentiation as evidenced by formation of mineralized nodules, induction of ALP activity and upregulation of odontogenic and angiogenic markers (P < 0.05). Scratch wound assays revealed that irisin significantly increased migration of HDPCs (P < 0.05). Phosphorylation of both MAPK and Akt was increased by irisin. MAPK and Akt inhibitors inhibited mineralization, cell migration and the increased expression of odontogenic and angiogenic markers.

CONCLUSIONS

Irisin promoted odontogenic differentiation and mineralization and has the potential for angiogenesis through activation of the MAPK and Akt signalling pathways in HDPCs.

Dux facilitates post-implantation development, but is not essential for zygotic genome activation†

Double homeobox genes are unique to eutherian mammals. It has been proposed that the DUXC clade of the double homeobox gene family, which is present in multicopy long tandem arrays, plays an essential role in zygotic genome activation (ZGA). We generated a deletion of the tandem array encoding the DUXC gene of mouse, Double homeobox (Dux), and found it surprisingly to be homozygous viable and fertile. We characterize the embryonic development and ZGA profile of knockout (KO) embryos, finding that zygotic genome activation still occurs, with only modest alterations in 2-cell embryo gene expression, no defect in in vivo preimplantation development, but an increased likelihood of post-implantation developmental failure, leading to correspondingly smaller litter sizes in the KO strain. While all known 2-cell specific Dux target genes are still expressed in the KO, a subset is expressed at lower levels. These include numerous genes involved in methylation, blastocyst development, and trophectoderm/placental development. We propose that rather than driving ZGA, which is a process common throughout the animal kingdom, DUXC genes facilitate a process unique to eutherian mammals, namely the post-implantation development enabled by an invasive placenta.

Dynamic Contrast-Enhanced MR Imaging of Nonenhancing T2 High-Signal-Intensity Lesions in Baseline and Posttreatment Glioblastoma: Temporal Change and Prognostic Value

BACKGROUND AND PURPOSE

The prognostic value of dynamic contrast-enhanced MR imaging on nonenhancing T2 high-signal-intensity lesions in patients with glioblastoma has not been thoroughly elucidated to date. We evaluated the temporal change and prognostic value for progression-free survival of dynamic contrast-enhanced MR imaging-derived pharmacokinetic parameters on nonenhancing T2 high-signal-intensity lesions in patients with glioblastoma before and after standard treatment, including gross total surgical resection.

MATERIALS AND METHODS

This retrospective study included 33 patients who were newly diagnosed with glioblastoma and treated with gross total surgical resection followed by concurrent chemoradiation therapy and adjuvant chemotherapy with temozolomide in a single institution. All patients underwent dynamic contrast-enhanced MR imaging before surgery as a baseline and after completion of maximal surgical resection and concurrent chemoradiation therapy. On the whole nonenhancing T2 high-signal-intensity lesion, dynamic contrast-enhanced MR imaging-derived pharmacokinetic parameters (volume transfer constant [K ^trans], volume of extravascular extracellular space [v _e]_, and blood plasma volume [v_p ]) were calculated. The Cox proportional hazards regression model analysis was performed to determine the histogram features or percentage changes of pharmacokinetic parameters related to progression-free survival.

RESULTS

Baseline median K ^trans, baseline first quartile K ^trans, and posttreatment median K ^trans were significant independent variables, as determined by univariate analysis (P < .05). By multivariate Cox regression analysis including methylation status of O⁶-methylguanine-DNA methyltransferase, baseline median K ^trans was determined to be the significant independent variable and was negatively related to progression-free survival (hazard ratio = 1.48, P = .003).

CONCLUSIONS

Baseline median K ^trans from nonenhancing T2 high-signal-intensity lesions could be a potential prognostic imaging biomarker in patients undergoing gross total surgical resection followed by standard therapy for glioblastoma.

Prognostic Predictions for Patients with Glioblastoma after Standard Treatment: Application of Contrast Leakage Information from DSC-MRI within Nonenhancing FLAIR High-Signal-Intensity Lesions

BACKGROUND AND PURPOSE

Attempts have been made to quantify the microvascular leakiness of glioblastomas and use it as an imaging biomarker to predict the prognosis of the tumor. The purpose of our study was to evaluate whether the extraction fraction value from DSC-MR imaging within nonenhancing FLAIR hyperintense lesions was a better prognostic imaging biomarker than dynamic contrast-enhanced MR imaging parameters for patients with glioblastoma.

MATERIALS AND METHODS

A total of 102 patients with glioblastoma who received a preoperative dynamic contrast-enhanced MR imaging and DSC-MR imaging were included in this retrospective study. Patients were classified into the progression (n = 87) or nonprogression (n = 15) groups at 24 months after surgery. We extracted the means and 95th percentile values for the contrast leakage information parameters from both modalities within the nonenhancing FLAIR high-signal-intensity lesions.

RESULTS

The extraction fraction 95th percentile value was higher in the progression-free survival group of >24 months than at ≤24 months. The median progression-free survival of the group with an extraction fraction 95th percentile value of >13.32 was 17 months, whereas that of the group of ≤13.32 was 12 months. In addition, it was an independent predictor variable for progression-free survival in the patients regardless of their ages and genetic information.

CONCLUSIONS

The extraction fraction 95th percentile value was the only independent parameter for prognostic prediction in patients with glioblastoma among the contrast leakage information, which has no statistically significant correlations with the DCE-MR imaging parameters.

Abstract P4-14-09: A nationwide data on the cardiovascular protective effect of tamoxifen and aromatase inhibitor in postmenopausal women with breast cancer

A large proportion of breast cancer patients receive hormonal therapy as their adjuvant treatment options. For postmenopausal women, the initial choice for the hormonal therapy is aromatase inhibitor (AI), and tamoxifen (TM) is reserved for women experiencing severe side effects against AI or having low bone density. An important but unresolved clinical question regarding the use of AI in postmenopausal women is the safety of AI regarding the risk cardiovascular events. Studies have shown inconsistent results over the cardiovascular safety of AI and TM. In this study, we investigated the risk of developing cardiovascular and cerebrovascular events in women with breast cancer who receive hormonal therapy using AI, TM, or both.

To this end, we used the National Health Insurance Sharing Service in Korea which is provided by National Health Insurance Service. The database provides anonymized insurance data for research purposes after the approval of the review committee. In the database, we identified 47,569 women with the age older than 55 who were diagnosed with breast cancer. Patients were classified as no hormonal treatment group (n=18,807), AI group (n=19,584), TM group (n=7,081), or Switch group (n=2,097). The Switch group was defined as the women with history of both AI and TM prescriptions. During the studied period, a total of 2,032 cardiovascular or cerebrovascular events (CVE) were recorded.

Overall, the women prescribed with TM had significantly less hazard ratio for developing CVE when compared to the women who did not receive any hormonal treatment (HR 0.809 95% C.I. 0.706-0.928). However, this protective effect of tamoxifen was not observed in either AI or Switch group (HR 0.917 95% C.I. 0.833-1.010, and HR 0.856 95% C.I. 0.695-1.053, respectively). The protective effect of TM was also similar in women older than 60 (HR 0.808 95% C.I. 0.696-0.938). The cardiovascular and cerebrovascular protective effects of tamoxifen was also substantial in high risk women defined by their family history of cardiovascular diseases and the diagnosis of hypertension or diabetes.

Our results suggest that the use of TM is associated with a substantial protective effect against developing cardiovascular or cerebrovascular events in women with breast cancer. However, the protective effect was not observed for women receiving AI. Our data suggest the potential tailored approach in hormonal treatment in breast cancer patients who are at high risk of cardiovascular of cerebrovascular events.

Citation Format: Moon H-G, Choi SH, Park Y, Jung JG, Ju YW, Kim KE, Kim Y, Lee E, Lee H-B, Han W, Noh D-Y, Yoon H-J. A nationwide data on the cardiovascular protective effect of tamoxifen and aromatase inhibitor in postmenopausal women with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-09.

Low level DUX4 expression disrupts myogenesis through deregulation of myogenic gene expression

Loss of silencing of the DUX4 gene on chromosome 4 causes facioscapulohumeral muscular dystrophy. While high level DUX4 expression induces apoptosis, the effects of low level DUX4 expression on human myogenic cells are not well understood. Low levels and sporadic expression of DUX4 have been reported in FSHD biopsy samples and myoblast cultures. Here, we show that a large set of human myogenic genes is rapidly deregulated by DUX4, including MYOD1 and MYF5, which are efficiently repressed even by low, non-toxic levels of DUX4. Human myoblasts modified to express low nontoxic levels of DUX4 were significantly impaired from differentiating into myotubes in vitro. Surprisingly, inhibition of differentiation does not require the transcriptional activation domain, thus is likely a feature of all mammalian DUX genes. DUX4 does not bind near the MYF5 gene, but has a prominent ChIP-seq peak within the MYF5 −118 kb enhancer. We find that when DUX4 binds at this site, it directs enhancer activity towards a nearby transcriptional start site for a noncoding nonfunctional RNA we name DIME (DUX4-induced MYF5 enhancer) transcript. These data highlight the anti-myogenic properties of DUX4 in human myogenic progenitor cells, and provide an example of enhancer disruption in the downregulation of MYF5.

Application of 3D Fast Spin-Echo T1 Black-Blood Imaging in the Diagnosis and Prognostic Prediction of Patients with Leptomeningeal Carcinomatosis

BACKGROUND AND PURPOSE

Contrast-enhanced 3D fast spin-echo T1 black-blood imaging selectively suppresses the signal of blood flow and could provide a higher contrast-to-noise ratio compared with contrast-enhanced 3D ultrafast gradient recalled echo (contrast-enhanced gradient recalled echo) and 2D spin-echo T1WI (contrast-enhanced spin-echo). The purpose of our study was to evaluate whether black-blood imaging can improve the diagnostic accuracy for leptomeningeal carcinomatosis compared with contrast-enhanced gradient recalled-echo and contrast-enhanced spin-echo and, furthermore, to determine whether the grade of leptomeningeal carcinomatosis evaluated on black-blood imaging is a significant predictor of progression-free survival.

MATERIALS AND METHODS

Leptomeningeal carcinomatosis (n = 78) and healthy (n = 31) groups were enrolled. Contrast-enhanced gradient recalled-echo, contrast-enhanced spin-echo, and black-blood imaging were separately reviewed, and a diagnostic rating (positive, indeterminate, or negative) and grading of leptomeningeal carcinomatosis were assigned. The diagnostic accuracies of the 3 imaging sequences were compared in terms of leptomeningeal carcinomatosis detection. The Kaplan-Meier and the Cox proportional hazards model analyses were performed to determine the relationship between the leptomeningeal carcinomatosis grade evaluated on black-blood imaging and progression-free survival.

RESULTS

Black-blood imaging showed a significantly higher sensitivity (97.43%) than contrast-enhanced gradient recalled-echo (64.1%) and contrast-enhanced spin-echo (66.67%) (P < .05). In terms of specificities, we did not find any significant differences among contrast-enhanced gradient recalled-echo (90.32%), contrast-enhanced spin-echo (90.32%), and black-blood imaging (96.77%) (P > .05). A Cox proportional hazards model identified the time to metastasis, Karnofsky Performance Scale status, and a combination of the leptomeningeal carcinomatosis grade with a linear pattern as independent predictors of progression-free survival (P < .05).

CONCLUSIONS

Black-blood imaging can improve the diagnostic accuracy and predict progression-free survival in patients with leptomeningeal carcinomatosis.

Magnetic resonance tumour regression grade and pathological correlates in patients with rectal cancer

BACKGROUND

Evidence to support the specific use of magnetic resonance tumour regression grade (mrTRG) is inadequate. The aim of this study was to investigate the pathological characteristics of mrTRG after chemoradiotherapy (CRT) for rectal cancer and the implications for surgery.

METHODS

Patients undergoing long-course CRT (45-50 Gy plus a booster dose of 4-6 Gy) for mid or low rectal cancer (cT3-4 or cN+ without metastasis) between 2011 and 2015 who had post-CRT rectal MRI before surgery were included retrospectively. Three board-certified experienced radiologists assessed mrTRG. mrTRG was correlated with pathological tumour regression grade (pTRG), ypT and ypN. In a subgroup of patients with mrTRG1-2 and no tumour spread (such as nodal metastasis) on MRI, the projected rate of completion total mesorectal excision (TME) if they underwent transanal excision (TAE) and had a ypT status of ypT2 or higher was estimated, and recurrence-free survival was calculated according to the operation (TME or TAE) that patients had actually received.

RESULTS

Some 439 patients (290 men and 149 women of mean(s.d.) age 62·2(11·4) years) were analysed. The accuracy of mrTRG1 for predicting pTRG1 was 61 per cent (40 of 66), and that for ypT1 or less was 74 per cent (49 of 66). For mrTRG2, these values were 22·3 per cent (25 of 112) and 36·6 per cent (41 of 112) respectively. Patients with mrTRG1 and mrTRG2 without tumour spread were ypN+ in 3 per cent (1 of 29) and 16 per cent (8 of 50) respectively. Assuming mrTRG1 or mrTRG1-2 with no tumour spread on post-CRT MRI as the criteria for TAE, the projected completion TME rate was 26 per cent (11 of 43) and 41·0 per cent (41 of 100) respectively. For the 100 patients with mrTRG1-2 and no tumour spread, recurrence-free survival did not differ significantly between TME (79 patients) and TAE (21) (adjusted hazard ratio 1·86, 95 per cent c.i. 0·42 to 8·18).

CONCLUSION

Patients with mrTRG1 without tumour spread may be suitable for TAE.

First Report of the Korean Lung Transplantation Registry

BACKGROUND

The Korean Organ Transplantation Registry (KOTRY) began to register lung transplants in 2015. This is an initial report on the status of patients receiving lung transplants over the past 2 years.

METHODS

We analyzed a total of 69 patients who received lung transplants in 2015 and 2016 and who registered with the KOTRY.

RESULTS

The 69 patients were treated in 5 institutions. The average (SD) donor age was 39.2 (12.6) years; there were 40 male patients. The average (SD) recipient age was 55.7 (10.0) years, and the number of male recipients was 46. A total of 66 patients underwent bilateral lung transplantation, 3 underwent single-lung transplantation, and 1 underwent simultaneous heart-lung transplantation. The most frequent indication for lung transplantation was idiopathic pulmonary fibrosis (35 patients), followed by connective tissue disease-related interstitial lung disease (9) and acute respiratory failure (8). Prior to transplantation, 23 patients required ventilator care, and 12 required extracorporeal membrane oxygenation while on the waiting list. Episodes of acute rejection during follow-up were reported in 4, 2, 1, and 1 patients at 3, 6, 9, and 12 months, respectively. Infections requiring hospitalization were reported in 27, 10, 4, and 3 patients at 3, 6, 9, and 12 months, respectively.

CONCLUSION

The establishment of KOTRY renders it possible to collect nationwide data on lung transplantation, improving research on the topic and clarifying clinical feasibility.

Feasibility of a text-based smoking cessation intervention in rural older adults

Text-based interventions are effective for smoking cessation, but have not been tested in rural older adults. The purpose of this study was to compare the feasibility, acceptability and preliminary efficacy of a text-based Scheduled Gradual Reduction (SGR) program to a non-SGR text messaging support condition among rural older adults. Adults over 60 years were randomized to either: (i) the SGR program (n = 20), a text-based program to reduce smoking over 4-weeks plus text-based support messages; or (ii) control (n = 20), receipt of text-based support messages only. Participants completed surveys at baseline and end of program to assess feasibility and acceptability of the intervention, and biochemically validated 7-day point prevalence cessation was assessed at end of treatment. Most participants (81%) reported reading all the messages they received. Participants found both interventions useful in quitting smoking (SGR = 57%, Control = 63%) and would recommend it to a friend (SGR = 72%, Control = 79%). Although not statically significant, the SGR group had a higher rate of biochemically validated cessation (SGR = 15%, Control = 5%, Cohen d = 0.67). Among those still smoking, the median percent reduction in cigarettes was 33.3% for both groups. Text-based cessation interventions are feasible, acceptable and can be easily disseminated to rural older adult tobacco users.

Smek1/2 is a nuclear chaperone and cofactor for cleaved Wnt receptor Ryk, regulating cortical neurogenesis

The receptor-like tyrosine kinase (Ryk), a Wnt receptor, is important for cell fate determination during corticogenesis. During neuronal differentiation, the Ryk intracellular domain (ICD) is cleaved. Cleavage of Ryk and nuclear translocation of Ryk-ICD are required for neuronal differentiation. However, the mechanism of translocation and how it regulates neuronal differentiation remain unclear. Here, we identified Smek1 and Smek2 as Ryk-ICD partners that regulate its nuclear localization and function together with Ryk-ICD in the nucleus through chromatin recruitment and gene transcription regulation. Smek1/2 double knockout mice displayed pronounced defects in the production of cortical neurons, especially interneurons, while the neural stem cell population increased. In addition, both Smek and Ryk-ICD bound to the Dlx1/2 intergenic regulator element and were involved in its transcriptional regulation. These findings demonstrate a mechanism of the Ryk signaling pathway in which Smek1/2 and Ryk-ICD work together to mediate neural cell fate during corticogenesis.

Heart Rate Variability Measurement in Sepsis Patients

Objectives

Inflammation makes an influence on autonomic nervous system and a change in autonomic nervous activity affects heart rate. Heart rate variability (HRV) test can quantify the autonomous nervous activity. In this study, we evaluated the meaning of heart rate variability in sepsis patients.

Methods

Heart rate variability test was performed for sepsis patients and healthy volunteers. Normalised low frequency power, reflecting sympathetic activity, was compared to acute physiology and chronic health evaluation II (APACHE II) score and mortality in emergency department sepsis (MEDS) score in sepsis patients. Then the patients were divided into four groups: 1) severe sepsis patients, 2) sepsis patients admitted to general ward, 3) sepsis patients discharged within 24 hours and 4) healthy volunteers. We obtained averages for the HRV results in all four groups. The receiver operating characteristics curve was examined to determine whether or not HRV variables could be used to triage sepsis patients.

Results

Correlations between normalised low frequency power (LFnu) with APACHE II score and MEDS score were −0.595 and −0.514, respectively. Low frequency power (LF) and LFnu values decreased in sepsis patients with the higher scores observed in the discharged sepsis patients and healthy volunteers. The areas under the curve for the values of LF and LFnu in the admission and discharge groups were 0.746 and 0.635, respectively (p<0.05).

Conclusion

Variables related to heart rate variability are significantly correlated with the severity of sepsis patients. Although the HRV test alone cannot accurately predict the disposition of sepsis patients, in the emergency room setting it helps to assign beds to sepsis patients within the triage system, and avoid over-population. (Hong Kong j.emerg.med. 2014;21:73-79)

Recurrent Obturator Hernia as a Cause of Nonspecific Abdominal Pain: A Case Report

Many patients visit the emergency department (ED) with abdominal pain. Sometimes, physicians are faced with diagnostic challenges, particularly for older patients. We recently had an elderly female patient who visited the ED several times with non-specific abdominal pain caused by an unusual hernia. One year before, an 81-year-old female visited our ED complaining of abdominal pain radiating to the right inguinal/femoral area. An incarcerated obturator hernia was found on an abdomino-pelvic computed tomography (CT) scan, and she underwent a laparoscopic hernioplasty. However, 1 year later, she revisited complaining of abdominal pain similar to the previous episode. Eventually, the diagnosis of recurrent obturator hernia was made, and a second operation was performed. An obturator hernia may be the cause of non-specific abdominal pain and small bowel obstruction in elderly emaciated females. Recognising the clinical signs and characteristics of this disease is necessary for a prompt diagnosis and treatment.

Comparison between the Prebolus T1 Measurement and the Fixed T1 Value in Dynamic Contrast-Enhanced MR Imaging for the Differentiation of True Progression from Pseudoprogression in Glioblastoma Treated with Concurrent Radiation Therapy and Temozolomide Chemotherapy

BACKGROUND AND PURPOSE

Glioblastoma is the most common primary brain malignancy and differentiation of true progression from pseudoprogression is clinically important. Our purpose was to compare the diagnostic performance of dynamic contrast-enhanced pharmacokinetic parameters using the fixed T1 and measured T1 on differentiating true from pseudoprogression of glioblastoma after chemoradiation with temozolomide.

MATERIALS AND METHODS

This retrospective study included 37 patients with histopathologically confirmed glioblastoma with new enhancing lesions after temozolomide chemoradiation defined as true progression (n = 15) or pseudoprogression (n = 22). Dynamic contrast-enhanced pharmacokinetic parameters, including the volume transfer constant, the rate transfer constant, the blood plasma volume per unit volume, and the extravascular extracellular space per unit volume, were calculated by using both the fixed T1 of 1000 ms and measured T1 by using the multiple flip-angle method. Intra- and interobserver reproducibility was assessed by using the intraclass correlation coefficient. Dynamic contrast-enhanced pharmacokinetic parameters were compared between the 2 groups by using univariate and multivariate analysis. The diagnostic performance was evaluated by receiver operating characteristic analysis and leave-one-out cross validation.

RESULTS

The intraclass correlation coefficients of all the parameters from both T1 values were fair to excellent (0.689-0.999). The volume transfer constant and rate transfer constant from the fixed T1 were significantly higher in patients with true progression (P = .048 and .010, respectively). Multivariate analysis revealed that the rate transfer constant from the fixed T1 was the only independent variable (OR, 1.77 × 10⁵) and showed substantial diagnostic power on receiver operating characteristic analysis (area under the curve, 0.752; P = .002). The sensitivity and specificity on leave-one-out cross validation were 73.3% (11/15) and 59.1% (13/20), respectively.

CONCLUSIONS

The dynamic contrast-enhanced parameter of rate transfer constant from the fixed T1 acted as a preferable marker to differentiate true progression from pseudoprogression.

Can Arterial Spin-Labeling with Multiple Postlabeling Delays Predict Cerebrovascular Reserve?

BACKGROUND AND PURPOSE

The effect of delayed transit time is the main source of error in the quantitative measurement of CBF in arterial spin-labeling. In the present study, we evaluated the usefulness of the transit time-corrected CBF and arterial transit time delay from multiple postlabeling delays arterial spin-labeling compared with basal/acetazolamide stress technetium Tc99m-hexamethylpropylene amineoxime (Tc99m-HMPAO) SPECT in predicting impairment in the cerebrovascular reserve.

MATERIALS AND METHODS

Transit time-corrected CBF maps and arterial transit time maps were acquired in 30 consecutive patients with unilateral ICA or MCA steno-occlusive disease (severe stenosis or occlusion). Internal carotid artery territory-based ROIs were applied to both perfusion maps. Additionally, impairment in the cerebrovascular reserve was evaluated according to both qualitative and quantitative analyses of the ROIs on basal/acetazolamide stress Tc99m-HMPAO SPECT using a previously described method. The area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of arterial spin-labeling in depicting impairment of the cerebrovascular reserve. The correlation between arterial spin-labeling and cerebrovascular reserve was evaluated.

RESULTS

The affected hemisphere had a decreased transit time-corrected CBF and increased arterial transit time compared with the corresponding values of the contralateral normal hemisphere, which were statistically significant (P < .001). The percentage change of transit time-corrected CBF and the percentage change of arterial transit time were independently differentiating variables (P < .001) for predicting cerebrovascular reserve impairment. The correlation coefficient between the arterial transit time and cerebrovascular reserve index ratio was -0.511.

CONCLUSIONS

Our results demonstrate that the transit time-corrected CBF and arterial transit time based on arterial spin-labeling perfusion MR imaging can predict cerebrovascular reserve impairment.

Added Value of Arterial Spin-Labeling MR Imaging for the Differentiation of Cerebellar Hemangioblastoma from Metastasis

BACKGROUND AND PURPOSE

In adults with only cerebellar masses, hemangioblastoma and metastasis are the 2 most important differential diagnoses. Our aim was to investigate the added value of arterial spin-labeling MR imaging for differentiating hemangioblastoma from metastasis in patients with only cerebellar masses.

MATERIALS AND METHODS

This retrospective study included a homogeneous cohort comprising patients with only cerebellar masses, including 16 hemangioblastomas and 14 metastases. All patients underwent enhanced MR imaging, including arterial spin-labeling. First, the presence or absence of a hyperperfused mass was determined. Next, in the hyperperfused mass, relative tumor blood flow (mean blood flow in the tumor divided by blood flow measured in normal-appearing cerebellar tissue) and the size ratio (size in the arterial spin-labeling images divided by size in the postcontrast T1WI) were measured. To validate the arterial spin-labeling findings, 2 observers independently evaluated the conventional MR images and the combined set of arterial spin-labeling images.

RESULTS

All patients with hemangioblastomas and half of the patients with metastases presented with a hyperperfused mass (P < .001). The size ratio and relative tumor blood flow were significantly larger for hemangioblastomas than for metastases (P < .001 and P = .039, respectively). The size ratio revealed excellent diagnostic power (area under the curve = 0.991), and the relative tumor blood flow demonstrated moderate diagnostic power (area under the curve = 0.777). The diagnostic accuracy of both observers was significantly improved after the addition of arterial spin-labeling; the area under the curve improved from 0.574 to 0.969 (P < .001) for observer 2 and from 0.683 to 1 (P < .001) for observer 2.

CONCLUSIONS

Arterial spin-labeling imaging can aid in distinguishing hemangioblastoma from metastasis in patients with only cerebellar masses.