Unveiling the potential of breast MRI: a game changer for BI-RADS 4A microcalcifications.

PURPOSE: To assess the diagnostic performance of breast MRI for BI-RADS 4A microcalcifications on mammography and propose a potential clinical pathway to avoid unnecessary biopsies. METHODS: Bibliometrics analysis of breast MRI and BI-RADS 4 was provided. A retrospective analysis was conducted on 139 women and 142 cases of BI-RADS 4A microcalcifications on mammography from Fudan University Shanghai Cancer Center. The mammographic BI-RADS level and the MRI reports were compared with the final pathological diagnosis. RESULTS: Much attention has been given to breast MRI and BI-RADS 4 in the literature. However, studies on BI-RADS 4A are limited. Pathological results showed 117 cases (82.4%) were benign lesions, malignant cases of 25 (17.6%) in our study. The positive predictive values (PPV), specificity, sensitivity and negative predictive values (NPV) of MRI were 44.2% (23/52), 75.2% (88/117), 92.0% (23/25), and 97.8% (88/90), respectively. Therefore, 75.2% (88/117) of biopsies for benign lesions could potentially be avoided. There were 2.2% (2/90) malignant lesions missed. Logistic regression indicated that patients who are postmenopausal (HR = 2.655, p = 0.012), have a history of breast cancer (family history) (HR = 2.833, p = 0.029), and exhibit clustered microcalcifications (HR = 2.179, p = 0.046) are more likely to have a higher MRI BI-RADS level. CONCLUSIONS: Breast MRI has the potential to improve the diagnosis of BI-RADS 4A microcalcifications on mammography. We propose a potential clinical pathway that patients with BI-RADS 4A on mammography who are premenopausal, have no personal history of breast cancer (family history) or have non-clustered distribution of calcifications can undergo MRI to avoid unnecessary biopsies.

Effect of Abiotic Factors on Fumosorinone Production from Cordyceps fumosorosea via Solid-State Fermentation.

Cordyceps fumosorosea is an important species in the genus of Cordyceps, containing a variety of bioactive compounds, including fumosorinone (FU). This study was a ground-breaking assessment of FU levels in liquid and solid cultures. The present study focused on the impacts of solid-state fermentation (SSF) using solid substrates (wheat, oat, and rice), as well as the effects of fermentation parameters (pH, temperature, and incubation period), on the generation of FU. All the fermentation parameters had significant effects on the synthesis of FU. In a study of 25 °C, 5.5 pH, and 21 days of incubation period combinations calculated -to give maximal FU production, it was found that the optimal values were 25 °C, 5.5 pH, and 21 days, respectively. In a solid substrate medium culture, FU could be produced from SSF. At 30 days, a medium composed of rice yielded the most FU (798.50 mg/L), followed by a medium composed of wheat and oats (640.50 and 450.50 mg/L), respectively. An efficient method for increasing FU production on a large scale could be found in this approach. The results of this study might have multiple applications in different industrial fermentation processes.

Histological diagnosis of unprocessed breast core-needle biopsy via stimulated Raman scattering microscopy and multi-instance learning.

Core-needle biopsy (CNB) plays a vital role in the initial diagnosis of breast cancer. However, the complex tissue processing and global shortage of pathologists have hindered traditional histopathology from timely diagnosis on fresh biopsies. In this work, we developed a full digital platform by integrating label-free stimulated Raman scattering (SRS) microscopy with weakly-supervised learning for rapid and automated cancer diagnosis on un-labelled breast CNB. Methods: We first compared the results of SRS imaging with standard hematoxylin and eosin (H&E) staining on adjacent frozen tissue sections. Then fresh unprocessed biopsy tissues were imaged by SRS to reveal diagnostic histoarchitectures. Next, weakly-supervised learning, i.e., the multi-instance learning (MIL) model was conducted to evaluate the ability to differentiate between benign and malignant cases, and compared with the performance of supervised learning model. Finally, gradient-weighted class activation mapping (Grad-CAM) and semantic segmentation were performed to spatially resolve benign/malignant areas with high efficiency. Results: We verified the ability of SRS in revealing essential histological hallmarks of breast cancer in both thin frozen sections and fresh unprocessed biopsy, generating histoarchitectures well correlated with H&E staining. Moreover, we demonstrated that weakly-supervised MIL model could achieve superior classification performance to supervised learnings, reaching diagnostic accuracy of 95% on 61 biopsy specimens. Furthermore, Grad-CAM allowed the trained MIL model to visualize the histological heterogeneity within the CNB. Conclusion: Our results indicate that MIL-assisted SRS microscopy provides rapid and accurate diagnosis on histologically heterogeneous breast CNB, and could potentially help the subsequent management of patients.

Discovery of Podofilox as a Potent cGAMP-STING Signaling Enhancer with Antitumor Activity.

Cyclic GMP-AMP (cGAMP) is a second messenger that activates the stimulator of interferon genes (STING) innate immune pathway to induce the expression of type I IFNs and other cytokines. Pharmacologic activation of STING is considered a potent therapeutic strategy in cancer. In this study, we used a cell-based phenotypic screen and identified podophyllotoxin (podofilox), a microtubule destabilizer, as a robust enhancer of the cGAMP-STING signaling pathway. We found that podofilox enhanced the cGAMP-mediated immune response by increasing STING-containing membrane puncta and the extent of STING oligomerization. Furthermore, podofilox changed the trafficking pattern of STING and delayed trafficking-mediated STING degradation. Importantly, the combination of cGAMP and podofilox had profound antitumor effects on mice by activating the immune response through host STING signaling. Together, these data provide insights into the regulation of cGAMP-STING pathway activation and demonstrate what we believe to be a novel approach for modulating this pathway and thereby promoting antitumor immunity.

LL-37 transports immunoreactive cGAMP to activate STING signaling and enhance interferon-mediated host antiviral immunity.

Cyclic 2',3'-GMP-AMP (cGAMP) binds to and activates stimulator of interferon genes (STING), which then induces interferons to drive immune responses against tumors and pathogens. Exogenous cGAMP produced by infected and malignant cells and synthetic cGAMP used in immunotherapy must traverse the cell membrane to activate STING in target cells. However, as an anionic hydrophilic molecule, cGAMP is not inherently membrane permeable. Here, we show that LL-37, a human host defense peptide, can function as a transporter of cGAMP. LL-37 specifically binds cGAMP and efficiently delivers cGAMP into target cells. cGAMP transferred by LL-37 activates robust interferon responses and host antiviral immunity in a STING-dependent manner. Furthermore, we report that LL-37 inducers vitamin D3 and sodium butyrate promote host immunity by enhancing endogenous LL-37 expression and its mediated cGAMP immune response. Collectively, our data uncover an essential role of LL-37 in innate immune activation and suggest new strategies for immunotherapy.

Research on the Method of Predicting Fractional Flow Reserve Based on Multiple Independent Risk Factors.

The use of diameter stenosis (DS), as revealed by coronary angiography, for predicting fractional flow reserve (FFR) usually results in a high error rate of detection. In this study, we investigated a method for predicting FFR in patients with coronary stenosis based on multiple independent risk factors. The aim of the study was to improve the accuracy of detection. First, we searched the existing literature to identify multiple independent risk factors and then calculated the corresponding odds ratios. The improved analytic hierarchy process (IAHP) was then used to determine the weighted value of each independent risk factor, based on the corresponding odds ratio. Next, we developed a novel method, based on the top seven independent risk factors with the highest weighted values, to predict FFR. This model was then used to predict the FFR of 253 patients with coronary stenosis, and the results were then compared with previous methods (DS alone and a simplified scoring system). In addition to DS, we identified a range of other independent risk factors, with the highest weighted values, for predicting FFR, including gender, body mass index, location of stenosis, type of coronary artery distribution, left ventricular ejection fraction, and left myocardial mass. The area under the receiver-operating characteristic curve (AUC) for the newly developed method was 84.3% (95% CI: 79.2-89.4%), which was larger than 65.3% (95% CI: 61.5-69.1%) of DS alone and 74.8% (95% CI: 68.4-81.2%) of the existing simplified scoring system. The newly developed method, based on multiple independent risk factors, effectively improves the prediction accuracy for FFR.

Branch flow distribution approach and its application in the calculation of fractional flow reserve in stenotic coronary artery.

OBJECTIVE: To calculate fractional flow reserve (FFR) based on computed tomography angiography (i.e., FFRCT) by considering the branch flow distribution in the coronary arteries. BACKGROUND: FFR is the gold standard to diagnose myocardial ischemia caused by coronary stenosis. An accurate and noninvasive method for obtaining total coronary blood flow is needed for the calculation of FFRCT. METHODS: A mathematical model for estimating the coronary blood flow rate and two approaches for setting the patient-specific flow boundary condition were proposed. Coronary branch flow distribution methods based on a volume-flow approach and a diameter-flow approach were employed for the numerical simulation of FFRCT. The values of simulated FFRCT for 16 patients were compared with their clinically measured FFR. RESULTS: The ratio of total coronary blood flow to cardiac output and the myocardial blood flow under the condition of hyperemia were 16.97% and 4.07 mL/min/g, respectively. The errors of FFRCT compared with clinical data under the volume-flow approach and diameter-flow approach were 10.47% and 11.76%, respectively, the diagnostic accuracies of FFRCT were 65% and 85%, and the consistencies were 95% and 90%. CONCLUSIONS: The mathematical model for estimating the coronary blood flow rate and the coronary branch flow distribution method can be applied to calculate the value of clinical noninvasive FFRCT.

Trend and survival benefit of contralateral prophylactic mastectomy among men with stage I-III unilateral breast cancer in the USA, 1998-2016.

PURPOSE: Our study aimed to explore temporal trends and survival benefit of contralateral prophylactic mastectomy (CPM) in male breast cancer (MBC). METHODS: Men with stage I-III unilateral breast cancer between 1998 and 2016 were identified from the surveillance, epidemiology, and end results (SEER). We compared CPM rate over the study period using the Cochrane-Armitage test for trend. Logistic regression model was used to test for factors predicting CPM. Survival analysis was conducted in patients who underwent CPM or unilateral mastectomy (UM) with a first diagnosis of unilateral breast cancer. Kaplan-Meier curve and univariate and multivariable Cox proportional hazards regression analyses were performed to compare overall survival (OS) and breast cancer-specific survival (BCSS) between CPM and UM groups. Propensity score matching was adopted to balance baseline characteristics. RESULTS: 5118 MBC cases were included in the present study, with 4.1% (n = 209) patients underwent CPM. The proportion of men undergoing CPM increased from 1.7 in 1998 to 6.3% in 2016 (P < 0.0001). Young age, recent years of diagnosis, higher tumor grade and lower T stage were significantly associated with CPM. A cohort of 3566 patients were enrolled in survival analysis with a median follow-up of 65 months. CPM was associated with better OS (HR 0.58, 95% CI 0.37-0.89, P = 0.022) rather than BCSS (HR 0.57, 95% CI 0.29-1.11, P = 0.153) compared with UM. In propensity score-matched model, CPM was not an independent prognostic factor for OS (HR 0.83, 95% CI 0.46-1.52, P = 0.553) and BCSS (HR 0.98, 95% CI 0.39-2.47, P = 0.970). CONCLUSION: Our study revealed a dramatic increase in CPM utilization among MBC, especially in young patients. However, CPM provides no survival benefit for MBC compared with UM, indicating the decision of CPM should be fully discussed.

Microcalcification-Based Tumor Malignancy Evaluation in Fresh Breast Biopsies with Hyperspectral Stimulated Raman Scattering.

Precise evaluation of breast tumor malignancy based on tissue calcifications has important practical value in the disease diagnosis, as well as the understanding of tumor development. Traditional X-ray mammography provides the overall morphologies of the calcifications but lacks intrinsic chemical information. In contrast, spontaneous Raman spectroscopy offers detailed chemical analysis but lacks the spatial profiles. Here, we applied hyperspectral stimulated Raman scattering (SRS) microscopy to extract both the chemical and morphological features of the microcalcifications, based on the spectral and spatial domain analysis. A total of 211 calcification sites from 23 patients were imaged with SRS, and the results were analyzed with a support vector machine (SVM) based classification algorithm. With optimized combinations of chemical and geometrical features of microcalcifications, we were able to reach a precision of 98.21% and recall of 100.00% for classifying benign and malignant cases, significantly improved from the pure spectroscopy or imaging based methods. Our findings may provide a rapid means to accurately evaluate breast tumor malignancy based on fresh tissue biopsies.

Transcriptional and epigenetic regulation of PD-1 expression.

Programmed cell death-1 (PD-1) is a co-inhibitory receptor that plays important roles in regulating T cell immunity and peripheral tolerance. PD-1 signaling prevents T cells from overactivation during acute infections, but it maintains T cell exhaustion during chronic infections. Tumor cells can exploit the PD-1 signaling pathway to evade antitumor immune responses. The PD-1 signaling pathway is also essential for maintaining peripheral tolerance and prevention of autoimmunity. PD-1 expression is strictly and differentially regulated by diverse mechanisms in immune cells. It is activated and repressed by distinct transcription factors in different circumstances. Moreover, epigenetic mechanisms are also involved in regulating PD-1 expression. In this review, we summarize the knowledge of the transcriptional and epigenetic regulation of PD-1 expression during different immune responses.

Value of stereotactic 11-gauge vacuum-assisted breast biopsy in non-palpable suspicious calcifications: an eight-year single institution experience with 587 patients.

BACKGROUND: Vacuum-assisted breast biopsy (VABB) has been routinely recommended for stereotactic intervention in cases of isolate mammographically-detected calcifications. Herein we aimed to evaluate and compare the diagnostic consistency and accuracy of calcified and noncalcified specimens obtained from same sites of sampling on mammography-visible calcifications. In addition, we presented the biopsy procedure and retrospectively evaluated the usefulness of VABB as well as the complications of this technique over an eight-year experience in our centre. METHODS: This single-institution observational cohort study included 587 patients referred for stereotactic 11-gauge VABB of 594 mammographically-detected calcifications between January 2010 and December 2018. The rate of histopathological underestimation, the false negative, the diagnostic consistency and accuracy between calcified and noncalcified specimens of VABB were comprehensively evaluated based on the surveillance data and final histopathological result of the surgical specimens. RESULTS: In total, 594 biopsy procedures were performed in 587 patients (mean age 46 years, range, 21-80 years). The average number of biopsy specimens was 14.7 (range, 9-21) per lesion. VABB pathological results revealed 471 (79.3%) benign, 39 (6.6%) high-risk, and 84 (14.1%) malignant cases. The diagnostic inconsistency between calcified and noncalcified specimens was 14.6% (105/123) for high-risk and malignant lesions. Furthermore, calcified specimens exhibited higher diagnostic accuracy of malignant lesion as compared with the noncalcified specimens (97.7% versus 82.6%, respectively). Underestimation rate for high-risk lesions and in situ carcinoma was 5.1% and 54.1%, respectively, along with a false negative rate of 6.25%. In addition, mild complications were reported with high patient tolerance. CONCLUSIONS: Stereotactic 11G-VABB might be preferred for the investigation of non-palpable mammographically-detected calcifications in terms of accuracy and safety profile. The high prevalence of diagnostic discordance between the specimens with and without calcifications revealed a higher value of calcified specimens in diagnosing high-risk and malignant calcifications.

The YdiU Domain Modulates Bacterial Stress Signaling through Mn2+-Dependent UMPylation.

Sensing stressful conditions and adjusting the cellular metabolism to adapt to the environment are essential activities for bacteria to survive in variable situations. Here, we describe a stress-related protein, YdiU, and characterize YdiU as an enzyme that catalyzes the covalent attachment of uridine-5'-monophosphate to a protein tyrosine/histidine residue, an unusual modification defined as UMPylation. Mn2+ serves as an essential co-factor for YdiU-mediated UMPylation. UTP and Mn2+ binding converts YdiU to an aggregate-prone state facilitating the recruitment of chaperones. The UMPylation of chaperones prevents them from binding co-factors or clients, thereby impairing their function. Consistent with the recent finding that YdiU acts as an AMPylator, we further demonstrate that the self-AMPylation of YdiU padlocks its chaperone-UMPylation activity. A detailed mechanism is proposed based on the crystal structures of Apo-YdiU and YdiU-AMPNPP-Mn2+ and on molecular dynamics simulation models of YdiU-UTP-Mn2+ and YdiU-UTP-peptide. In vivo data demonstrate that YdiU effectively protects Salmonella from stress-induced ATP depletion through UMPylation.

RNF144A functions as a tumor suppressor in breast cancer through ubiquitin ligase activity-dependent regulation of stability and oncogenic functions of HSPA2.

Deregulation of E3 ubiquitin ligases is intimately implicated in breast cancer pathogenesis and progression, but the underlying mechanisms still remain elusive. Here we report that RING finger protein 144A (RNF144A), a poorly characterized member of the RING-in-between-RING family of E3 ubiquitin ligases, functions as a tumor suppressor in breast cancer. RNF144A was  downregulated in a subset of primary breast tumors and restoration of RNF144A suppressed breast cancer cell proliferation, colony formation, migration, invasion in vitro, tumor growth, and lung metastasis in vivo. In contrast, knockdown of RNF144A promoted malignant phenotypes of breast cancer cells. Quantitative proteomics and biochemical analysis revealed that RNF144A interacted with and targeted heat-shock protein family A member 2 (HSPA2), a putative oncoprotein that is frequently upregulated in human cancer and promotes tumor growth and progression, for ubiquitination and degradation. Notably, the ligase activity-defective mutants of RNF144A impaired its ability to induce ubiquitination and degradation of HSPA2, and to suppress breast cancer cell proliferation, migration, and invasion as compared with its wild-type counterpart. Moreover, RNF144A-mediated suppression of breast cancer cell proliferation, migration, and invasion was rescued by ectopic HSPA2 expression. Clinically, low RNF144A and high HSPA2 expression in breast cancer patients was correlated with aggressive clinicopathological characteristics and decreased overall and disease-free survival. Collectively, these findings reveal a previously unappreciated role for RNF144A in suppression of breast cancer growth and metastasis, and identify RNF144A as the first, to our knowledge, E3 ubiquitin ligase for HSPA2 in human cancer.

Phosphorylated Rasal2 facilitates breast cancer progression.

BACKGROUND: Rasal2 has diametric effects on progression of oestrogen receptor-positive (ER+) and -negative (ER-) breast cancers. The relevant causes are unknown. It is also unknown whether the effects of Rasal2 are mediated by an exosome-transport process. METHODS: Exosomes were purified from breast cancer cells and identified by transmission electron microscopy and flow cytometry analysis. In vivo and in vitro experiments were conducted to investigate the role of Rasal2 in exosome-mediated breast cancer progression. Western blot analysis was performed to detect Rasal2 and p-Rasal2 (phosphorylated Rasal2) expression in ER+/ER- breast cancer cells and in exosomes, cancer tissues and blood of patients with ER+ or ER- breast cancer. FINDINGS: Phosphorylation of Rasal2 at Serine 237 promoted tumour growth in both ER+ and ER- tumour cells and tissues. The functions of both p-Rasal2 and non-p-Rasal2 (non-phosphorylated-Rasal2) in the modulation of breast cancer progression are exosome-mediated. p-Rasal2 expression in ER+ breast cancer cells and exosomes, cancer tissues and blood was significantly lower than in ER- tumour cells and patients. INTERPRETATION: p-Rasal2 facilitates tumour progression in both ER+ and ER- breast cancers. The ratio of p-Rasal2/non-p-Rasal2 in ER+ and ER- breast cancers is one of the factors deciding the role of Rasal2 (or total Rasal2) as a suppressor in ER+ breast cancers or as a promoter in ER- breast cancers. Targeting the phosphorylation of Rasal2 machinery may therefore be useful as a therapy to restrain breast cancer progression by reducing p-Rasal2/non-p-Rasal2 ratio, especially in ER- breast cancers. FUND: NSFC and Hong Kong Research Grants Council.

Cutting Edge: USP27X Deubiquitinates and Stabilizes the DNA Sensor cGAS to Regulate Cytosolic DNA-Mediated Signaling.

Cyclic GMP-AMP synthase (cGAS), a cytosolic DNA sensor, catalyzes the formation of the second messenger 2'3'-cGAMP that binds to STING and triggers the type I IFN signaling. Activation of cGAS can be modulated by several protein posttranslational modifications, including ubiquitination. However, the cGAS activation regulated by protein deubiquitination remains poorly understood. In this study, we identified that deubiquitinase USP27X could interact with cGAS and cleave K48-linked polyubiquitination chains from cGAS, leading to cGAS stabilization. Consistently, knockout of Usp27x in mice macrophages resulted in an accelerated turnover of cGAS, decreased cGAMP production, phosphorylation of TBK1 and IRF3, and IFN-ß production. Furthermore, Usp27x knockout mice macrophages showed impaired innate antiviral responses against HSV type 1 infection. Our data suggest that USP27X is a novel regulator of the cGAS-STING cytosolic DNA sensing pathway.

Is core needle biopsy effective at diagnosing male breast lesions?

PURPOSE: The objective of this study was to examine the diagnostic accuracy of sonographically guided core needle biopsy (CNB) of breast lesions in men. METHODS: This was a retrospective study where we analyzed consecutive sonographically guided 14-gauge CNB results on 234 male breast lesions. The CNB accuracy is determined by the comparison between the CNB and its corresponding excisional biopsy or to long-term follow-up imaging. RESULTS: Sonographically guided CNB was effective to collect satisfactory samples from all 234 lesions. Out of those, 58.55% (137/234) were benign, 38.0% (89/234) were malignant, 1.71% (4/234) were papilloma with atypia and 1.71% (4/234) were atypical ductal hyperplasia lesions. Underestimation occurred in 3.4% (8/234) of the lesions. As for the detection of breast malignancy, the sensitivity of the CNB is 98.9%, specificity is 100%, negative predictive value is 99.3%, positive predictive value is 100%, false positive is 0% and false negative is 1.1%. The overall accuracy of sonographically guided CNB as a diagnostic tool is 99.6%. CONCLUSION: Sonographically guided 14-gauge CNB is an accurate, reliable and low invasive procedure for assessing breast lesions in men. Triple tests and follow-up checks of benign cases are essential for a successful breast biopsy program in men.

Rapid histology of laryngeal squamous cell carcinoma with deep-learning based stimulated Raman scattering microscopy.

Maximal resection of tumor while preserving the adjacent healthy tissue is particularly important for larynx surgery, hence precise and rapid intraoperative histology of laryngeal tissue is crucial for providing optimal surgical outcomes. We hypothesized that deep-learning based stimulated Raman scattering (SRS) microscopy could provide automated and accurate diagnosis of laryngeal squamous cell carcinoma on fresh, unprocessed surgical specimens without fixation, sectioning or staining. Methods: We first compared 80 pairs of adjacent frozen sections imaged with SRS and standard hematoxylin and eosin histology to evaluate their concordance. We then applied SRS imaging on fresh surgical tissues from 45 patients to reveal key diagnostic features, based on which we have constructed a deep learning based model to generate automated histologic results. 18,750 SRS fields of views were used to train and cross-validate our 34-layered residual convolutional neural network, which was used to classify 33 untrained fresh larynx surgical samples into normal and neoplasia. Furthermore, we simulated intraoperative evaluation of resection margins on totally removed larynxes. Results: We demonstrated near-perfect diagnostic concordance (Cohen's kappa, κ > 0.90) between SRS and standard histology as evaluated by three pathologists. And deep-learning based SRS correctly classified 33 independent surgical specimens with 100% accuracy. We also demonstrated that our method could identify tissue neoplasia at the simulated resection margins that appear grossly normal with naked eyes. Conclusion: Our results indicated that SRS histology integrated with deep learning algorithm provides potential for delivering rapid intraoperative diagnosis that could aid the surgical management of laryngeal cancer.

Spindle cell sarcoma: a SEER population-based analysis.

Due to the substantial limitation of study population, Spindle cell sarcoma (SCS) was unexplored comprehensively. In this study, we investigated the clinical characteristics and disease specific prognostic factors of SCS. 3299 SCS cases were identified and extracted from Surveillance, Epidemiology, and End Results (SEER) database (1973-2017). White people account for 79.1% with median age of 57 years without predominance in any gender. Significant disease specific survival (DSS) and overall survival (OS) were found differentiated in age, T stage, N stage, M stage, AJCC stage, SEER historic stage, tumor locations, surgery, and pathologic grade. In the multivariate Cox analysis, the age >64 years (for DSS, P < 0.001 and for OS, P < 0.001; Reference age ≤64 years), AJCC stage III (for DSS, P = 0.006 and for OS, P = 0.04; Reference: AJCC stage I), and non-surgical treatment (for DSS, P < 0.001 and for OS, P < 0.001; Reference: surgery) were independently associated with worse DSS and OS. In brief, our study demonstrated that SCS mostly found in white people at fifth to seventh decades of life without gender predilection. The patient's age, AJCC stage, tumor location and surgery were independent prognostic indicators for both DSS and OS of SCS.

Epigenetic silencing of RNF144A expression in breast cancer cells through promoter hypermethylation and MBD4.

Emerging evidence shows that ring finger protein 144A (RNF144A), a poorly characterized member of the Ring-between-Ring (RBR) family of E3 ubiquitin ligases, is a potential tumor suppressor gene. However, its regulatory mechanism in breast cancer remains undefined. Here, we report that RNF144A promoter contains a putative CpG island and the methylation levels of RNF144A promoter are higher in primary breast tumors than those in normal breast tissues. Consistently, RNF144A promoter methylation levels are associated with its transcriptional silencing in breast cancer cells, and treatment with DNA methylation inhibitor 5-Aza-2-deoxycytidine (AZA) reactivates RNF144A expression in cells with RNF144A promoter hypermethylation. Furthermore, genetic knockdown or pharmacological inhibition of endogenous methyl-CpG-binding domain 4 (MBD4) results in increased RNF144A expression. These findings suggest that RNF144A is epigenetically silenced in breast cancer cells by promoter hypermethylation and MBD4.