Analysis of m7G-Related signatures in the tumour immune microenvironment and identification of clinical prognostic regulators in breast cancer.

BACKGROUND: Breast cancer is a malignant tumour that seriously threatens women's life and health and exhibits high inter-individual heterogeneity, emphasising the need for more in-depth research on its pathogenesis. While internal 7-methylguanosine (m7G) modifications affect RNA processing and function and are believed to be involved in human diseases, little is currently known about the role of m7G modification in breast cancer. METHODS AND RESULTS: We elucidated the expression, copy number variation incidence and prognostic value of 24 m7G-related genes (m7GRGs) in breast cancer. Subsequently, based on the expression of these 24 m7GRGs, consensus clustering was used to divide tumour samples from the TCGA-BRCA dataset into four subtypes based on significant differences in their immune cell infiltration and stromal scores. Differentially expressed genes between subtypes were mainly enriched in immune-related pathways such as 'Ribosome', 'TNF signalling pathway' and 'Salmonella infection'. Support vector machines and multivariate Cox regression analysis were applied based on these 24 m7GRGs, and four m7GRGs-AGO2, EIF4E3, DPCS and EIF4E-were identified for constructing the prediction model. An ROC curve indicated that a nomogram model based on the risk model and clinical factors had strong ability to predict the prognosis of breast cancer. The prognoses of patients in the high- and low-TMB groups were significantly different (p = 0.03). Moreover, the four-gene signature was able to predict the response to chemotherapy. CONCLUSIONS: In conclusion, we identified four different subtypes of breast cancer with significant differences in the immune microenvironment and pathways. We elucidated prognostic biomarkers associated with breast cancer and constructed a prognostic model involving four m7GRGs. In addition, we predicted the candidate drugs related to breast cancer based on the prognosis model.

Breast Magnetic Resonance Imaging Can Predict Ki67 Discordance Between Core Needle Biopsy and Surgical Samples.

BACKGROUND: Disagreement in assessments of Ki67 expression based on core-needle biopsy and matched surgical samples complicates decisions in the treatment of breast cancer. PURPOSE: To examine whether preoperative breast MRI could be useful in predicting Ki67 discordance between core-needle biopsy and surgical samples. STUDY TYPE: Retrospective. POPULATION: Three hundred and sixty-five breast cancer patients with MRI scans and having both core-needle biopsy and surgical samples from 2017 to 2019. FIELD STRENGTH/SEQUENCE: 3.0 T, T2-weighted iterative decomposition of water and fat with echo asymmetry and least squares estimation sequence, diffusion-weighted sequence using b-values 0/1000, dynamic contrast enhanced image by volume imaged breast assessme NT. ASSESSMENT: We collected clinicopathologic variables and preoperative MRI features (tumor size, lesion type, shape of mass, spiculated margin, internal enhancement, peri-tumoral edema, intra-tumoral necrosis, multifocal/multicentric, apparent diffusion coefficient [ADC] minimum, ADC mean, ADC maximum, ADC difference). STATISTICAL TESTS: K-means clustering, multivariable logistic regression, receiver operating characteristic curve. RESULTS: Sixty-one patients showed Ki67 discordance and 304 patients show Ki67 concordance according to our definition using K-means clustering. Multivariable regression analysis showed that the following parameters were independently associated with Ki67 discordance: peri-tumoral edema, odds ratio (OR) 2.662, 95% confidence interval (CI) 1.432-4.948; ADCmin ≤ 0.829 × 10-3  mm2 /sec, OR 2.180, 95% CI 1.075-4.418; and ADCdiff > 0.317 × 10-3  mm2 /sec, OR 3.365, 95% CI 1.698-6.669. This multivariable model resulted in an AUC of 0.758 (95% CI 0.711-0.802) with sensitivity and specificity being 0.803 and 0.621, respectively. CONCLUSION: Presence of peri-tumoral edema, smaller ADCmin and greater ADCdiff in preoperative breast MRI may indicate high risk of Ki67 discordance between core-needle biopsy and surgical samples. For patients with these MRI-based risk factors, clinicians should not rely on Ki67 assessment only from core-needle biopsy.

Ring finger protein 126 promotes breast cancer metastasis and serves as a potential target to improve the therapeutic sensitivity of ATR inhibitors.

BACKGROUND/AIMS: This study explores the relationship between the E3 ubiquitin ligase Ring finger protein 126 (RNF126) and early breast cancer metastasis and tests the hypothesis that RNF126 determines the efficacy of inhibitors targeting Ataxia telangiectasia mutated and Rad3-related kinase (ATR). METHODS: Various metastasis-related genes were identified by univariable Cox proportional hazards regression analysis based on the GSE11121 dataset. The RNF126-related network modules were identified by WGCNA, whereas cell viability, invasion, and migration assays were performed to evaluate the biological characteristics of breast cancer cells with or without RNF126 knockdown. MTT, immunoblotting, immunofluorescence, and DNA fiber assays were conducted to determine the efficiency of ATR inhibitor in cells with or without RNF126 knockdown. RESULTS: RNF126 was associated with early breast cancer metastasis. RNF126 promoted breast cancer cell proliferation, growth, migration, and invasion. ATR inhibitors were more effective at killing breast cancer cells with intact RNF126 due to replication stress compared with the corresponding cells with RNF126 knockdown. Cyclin-dependent kinase 2 (CDK2) was involved in regulating replication stress in breast cancer cells with intact RNF126. CONCLUSION: A high level of expression of RNF126 in early breast cancer patients without lymph node metastases may indicate a high-risk type of metastatic disease, possibly due to RNF126, which may increase breast cancer cell proliferation and invasion. RNF126-expressing breast cancer cells exhibit CDK2-mediated replication stress that makes them potential targets for ATR inhibitors.

A functional liver imaging score for preoperative prediction of liver failure after hepatocellular carcinoma resection.

OBJECTIVES: Posthepatectomy liver failure (PHLF) is a challenging complication after resection to treat hepatocellular carcinoma (HCC), and it is associated with high mortality. Preoperative prediction of PHLF may improve patient subsequent and reduce such mortality. This study examined whether a functional liver imaging score (FLIS) based on preoperative gadoxetic acid-enhanced magnetic resonance imaging (MRI) could predict PHLF. MATERIALS AND METHODS: The study included 502 patients who underwent preoperative gadoxetic acid-enhanced MRI, followed by HCC resection. Significant preoperative predictors of PHLF were identified using logistic regression analysis. The ability of FLIS to predict PHLF was evaluated using receiver operating characteristic curves, and its predictive power was compared to that of the model for end-stage liver disease (MELD) score, albumin-bilirubin (ALBI) score, and indocyanine green 15-min retention rate (ICG-R15). RESULTS: In multivariate analysis, PHLF was independently associated with FLIS (OR 0.452, 95% CI 0.361 to 0.568, p < 0.001) and major resection (OR 1.898, 95% CI 1.057 to 3.408, p = 0.032). FLIS was associated with a higher area under the receiver operating characteristic curve (0.752) than the MELD score (0.557), ALBI score (0.609), or ICG-R15 (0.605) (all p < 0.05). Patients with FLIS ≤ 4 who underwent major resection were at 9.4-fold higher risk of PHLF than patients with lower FLIS who underwent minor resection. CONCLUSION: FLIS is an independent predictor of PHLF, and it may perform better than the MELD score, ALBI score, and ICG-R15 clearance. We propose treating elevated FLIS and major resection as risk factors for PHLF. KEY POINTS: • A functional liver imaging score can independently predict posthepatectomy liver failure in patients with HCC. • The score may predict such failure better than MELD and ALBI scores and ICG-R15. • Patients with scores ≤ 4 who undergo major hepatic resection may be at nearly tenfold higher risk of posthepatectomy liver failure.

Risk and protective factors of Internet gaming disorder among Chinese people: A meta-analysis.

OBJECTIVES: Effective prevention and intervention of Internet gaming disorder require the identification of risk and protective factors. This study aims to exhaustively review the risk and protective factors of Internet gaming disorder among Chinese people. METHOD: We searched for articles published from database inception to February 2020 in MEDLINE, PsycINFO, Embase, PubMed, Web of Science and two Chinese databases, CNKI and Wanfang Data. Studies were included in the meta-analysis if they addressed Internet gaming disorder, sampled people in China, presented correlational factors of Internet gaming disorder and reported the effect sizes for correlations. Reviewers independently selected the studies, assessed their validity and extracted the data. Pooled Pearson's correlations were calculated using the random effects model. RESULT: In the meta-analysis, 153 studies covering 115,975 subjects were included. We identified 56 risk factors and 28 protective factors. Most risk factors strongly correlated with Internet gaming disorder fell into the category of maladaptive cognitions and motivations. Other factors that showed high effect sizes fell into various categories, including psychopathological characteristics, personality traits, cognition emotion regulation style and gaming-related factors. The only protective factor strongly correlated with Internet gaming disorder was self-control. We found that the factors related to the 'environments' show modest effect sizes compared to those related to the individual. The pooled effect sizes for most factors were not influenced by outliers and publication bias. CONCLUSION: Factors strongly correlated with Internet gaming disorder, especially maladaptive cognitions and motivations, are more likely to be proximal correlates of Internet gaming disorder and may be considered the focus of interventions. We encourage further empirical and experimental studies to examine the causal pathway and the treatment efficacy.

Downregulation of TRPC4 and TRPC5 Inhibits Smooth Muscle Cell Proliferation without Affecting Endothelial Cell Proliferation.

Aims: The main treatment for coronary heart disease is percutaneous coronary intervention (PCI), and drug-eluting stents are designed to inhibit vascular smooth muscle cell (VSMCs) proliferation and migration causing restenosis by releasing pharmacological agents into the vessel wall. Once drug-eluting stents are deployed, these pharmacological agents exert many biological effects in the coronary circulation, not only inhibition of VSMCs but also extension to vascular endothelial cells (VECs). The purpose of this study was to explore target molecules that inhibit VSMCs proliferation without affecting VECs. Methods: mRNA and protein expressions of transient receptor potential channels (TRPCs) in cultured VSMCs and VECs were determined by western blotting and RT-qPCR. VSMCs and VECs proliferation was evaluated using CCK-8 assays and western blotting of proliferating cell nuclear antigen (PCNA). Calcium backfilling assays were performed to detect intracellular calcium ion concentration in cultured VSMCs and VECs. Results: The TRPC6 expression was more abundant in VECs than VSMCs, while TRPC4 and TRPC5 expressions were more abundant in VSMCs than VECs. Knockdown of TRPC4 or TRPC5 alone had no remarkable inhibitory effect on VSMC proliferation. Synergistic knockdown of TRPC4 and TRPC5 inhibited the proliferation of VSMCs, declined the expression of the PCNA, and reduced the intracellular calcium ion concentration but not VECs. Conclusion: These data suggest that concurrent inhibition of TRPC4 and TRPC5 inhibits VSMCs proliferation without affecting VECs, thus providing novel targets for developing pharmacological agents for drug-eluting stents.

The mental health of women with polycystic ovary syndrome: a systematic review and meta-analysis.

Polycystic ovary syndrome (PCOS) has been proposed to be associated with several mental health problems, including anxiety, depression, diminished sexual satisfaction, and lowered health-related quality of life, etc. A systematic review and meta-analysis of published literature was conducted comparing the mental health of women with and without PCOS. Ten English and Chinese databases were searched up to 12/31/2018. Random-effects models were introduced, and subgroup analysis, sensitivity test, and meta-regression were carried out to determine the source for heterogeneity among studies. Forty-six studies, including 30,989 participants (9265 women with PCOS and 25,638 controls), were qualified for review according to the inclusion criteria. Twenty-eight studies reported depression symptoms, 22 studies were on anxiety, 16 studies showed quality of life (QoL) status, 12 studies were about sexual dysfunction, five on emotional distress, four on binge eating, and four on somatization. Women with PCOS reported significantly higher depression (SMD = 0.64; 95% CI 0.50-0.78), anxiety (SMD = 0.63; 95% CI 0.50-0.77), lower QoL (SMD = - 0.55; 95% CI -0.69 to -0.40), and not significant sexual dysfunction (SMD = - 0.24; 95% CI - 0.49 to 0.01). Studies from different countries, adopting various diagnosis criteria, using diverse instruments, as well as in different years, have reported heterogenetic results. Women with PCOS in China reported a larger effect size of depression and anxiety than patients from other countries. The results of this study have indicated that women with PCOS suffer from depression, anxiety, and experience a lower quality of life, whereas their sexual function is not distinct from that of healthy women. Psychological health care interventions for women with PCOS were addressed.

Clinical utility of the additional use of blue dye for indocyanine green for sentinel node biopsy in breast cancer.

BACKGROUND: Indocyanine green (ICG) is widely used as a tracer in sentinel lymph node biopsy (SLNB) of patients with breast cancer. Whether SLNB performance can be improved by supplementing ICG with methylene blue dye remains controversial. This study compared the performance of SLNB when ICG was used alone or with blue dye. MATERIALS AND METHODS: Consecutive patients with T1-3 primary breast cancer at our hospital were recruited into our study and randomized to undergo SLNB with ICG alone (n = 62) or with the combination of ICG and blue dye (n = 65). We compared the two methods in terms of identification rate, number and detection time of sentinel lymph nodes (SLNs) removed. RESULTS: SLN identification rate were similar in the absence (95.2%) or presence of blue dye (98.5%, P = 0.578) but significantly, more average nodes were removed when blue dye was used (3.8 ± 1.5 versus 2.7 ± 1.2, P = 0.000), and the average time for detecting each SLN was significantly shorter (3.91 ± 1.87 versus 5.65 ± 2.95 min; P = 0.000). No patient in the study experienced severe adverse reactions or complications. Recurrence of axillary node was detected in one patient (1.6%) using ICG alone but not in any patients using ICG and blue dye. CONCLUSIONS: The efficiency and sensitivity of SLNB can be improved by combining ICG with blue dye.

Effectiveness of an integrated motivational cognitive-behavioral group intervention for adolescents with gaming disorder: a randomized controlled trial.

AIMS, DESIGN AND SETTING: The aim of this study was to test the efficacy of the integrated cognitive-behavioral therapy with a strength-based motivational approach [integrated cognitive-behavioral therapy (ICBT)] intervention to change gaming disorder (GD) symptoms and other outcomes and to study the therapeutic mechanism. A two-arm parallel randomized waiting-list controlled trial with 3- and 6-month follow-ups were conducted in a secondary vocational school in mainland China. PARTICIPANTS: Participants comprised 77 Chinese adolescents with GD symptoms with a mean age of 16.36 years [standard deviation (SD) = 0.93]; 88.3% were male INTERVENTIONS: Participants were randomized into an ICBT group (n = 38) and a waiting-list control (WLC, n = 39) group. ICBT intervention comprised eight weekly sessions to encourage participants to identify their interests and strengths and set goals for developing personally meaningful real-life activities. MEASUREMENTS AND FINDINGS: The outcomes were measured at pre-treatment (t0 ), post-treatment (t1 ), 3-month (t2 ) and 6-month (t3 ) follow-ups. The primary outcome was GD symptoms at t3. Secondary outcomes included GD symptoms at t1 and t2 , and gaming motivation, maladaptive gaming cognition, depression and anxiety symptoms at t1 , t2 and t3 . With the intention-to-treat principle, the GD scores at t3 were significantly different between the CBT and WLC groups [mean difference 62.08 (SD = 10.48) versus 73.64 (SD = 11.70); Hedges' g = 1.15, 95% confidence interval = 0.67-1.62]. Linear mixed-effects modeling showed significant group × time interaction for the secondary outcomes (P < 0.01), with a moderate to strong between-group effect size in the reduction in depression symptoms (g = 0.67-0.84) and anxiety symptoms (g = 0.6-0.64). Path analysis shows ICBT leads to GD reduction through reducing gaming motivation and maladaptive gaming cognition. CONCLUSIONS: An integrated cognitive-behavioral therapy with strength-based motivational approach intervention reduced gaming disorder symptoms and time spent gaming over a 6-month period by decreasing maladaptive gaming motivation and cognition.

A Dual-Mode Imaging Nanoparticle Probe Targeting PD-L1 for Triple-Negative Breast Cancer.

Chemotherapy has remained the mainstay of treatment of triple-negative breast cancer; however, it is significantly limited by the associated side effects. PD-1/PD-L1 immune checkpoint inhibition therapy (ICI) has been a breakthrough for this patient population in recent years. PD-L1 expression is crucial in immunotherapy since it is a major predictor of PD-1/PD-L1 antibody response, emphasizing the significance of monitoring PD-L1 expression. Nonetheless, it is hard to assess the expression of PD-L1 before surgery, which has highlighted the urgency for a precise and noninvasive approach. Herein, we prepared a dual-mode imaging nanoparticle probe to detect PD-L1. The particle size, zeta potential, biocompatibility, and imaging ability of NPs were characterized. The synthesized NPs showed slight cytotoxicity and good T2 relaxivity. The targeted NPs accumulated more in 4T1 cells than nontargeted NPs in vitro. The in vivo experiment further demonstrated the distribution of targeted NPs in tumor tissues, with changes in NIRF and MR signals observed. Our study indicated that SPIO-aPD-L1-Cy5.5 NPs can be used to monitor PD-L1 expression in breast cancer as NIRF/MR contrast agents.

Aquaporin 1 knockdown inhibits triple-negative breast cancer cell proliferation and invasion in vitro and in vivo.

Aquaporin 1 (AQP1) contributes to the progression of several cancer types, but its potential involvement in triple-negative breast cancer (TNBC) is unclear. The aim of the present study was to examine the role of AQP1 in cell proliferation and invasion in TNBC. Reverse transcription-quantitative PCR analysis and western blotting were used to detect AQP1 expression in different cell lines. A short hairpin (sh)RNA targeting AQP1 was established and transfected into MDA-MB-231 breast cancer cells. To investigate the effects of AQP1 knockdown, breast cancer cell proliferation, migration and invasion were evaluated by Cell Counting Kit-8 and Transwell assays. Furthermore, the volume and weight of tumor xenografts in mice were measured to evaluate breast cancer growth ability. The results revealed that the levels of AQP1 were higher in the MDA-MB-231 cell line compared with those in other breast cancer cell lines (MCF-7 and SK-BR-3) and a normal mammary epithelial cell line (MCF-10A). The shRNA targeting AQP1 effectively downregulated AQP1 expression at the mRNA and protein levels, and markedly suppressed TNBC cell proliferation, migration and invasion in vitro, and tumor growth in vivo. These results suggested that AQP1 may serve as a potential therapeutic target in TNBC.

A novel risk model to predict first-ever ischemic stroke in heart failure with reduced ejection fraction.

Patients with heart failure are at increased risk for ischemic stroke. We aim to develop a more accurate stroke risk prediction tools identify high-risk patients with heart failure with reduced ejection fraction (HFrEF). Patient data were extracted retrospectively from the electronic medical database between January 2009 and February 2019. Univariate and multivariate Cox regression analysis were performed to identify independent predictors, which were utilized to construct a nomogram for predicting ischemic stroke. AUROC analysis was used to compare the prognostic value between the new risk score and CHADS2/CHA2DS2-VASc scores. In 6087 patients with HFrEF, the risk of first-ever ischemic stroke was 5.8% events/pts-years (n=468) during 8007.2 person-years follow-up. A nomogram constructed by integrating 6 variables, including age, atrial fibrillation (AF), deep vein thrombosis (DVT), d-dimer, anticoagulant use and spontaneous echocardiographic contrast (SEC)/left ventricular thrombus (LVT), exhibited a greater area under the curve of 0.727, 0.728 and 0.714 than that by CHADS2 score (0.515, 0.522 and 0.540), and by CHA2DS2-VASc score (0.547, 0.553 and 0.562) for predicting first-ever ischemic stroke at hospitalization, 30-day and 6-month follow-up (all p<0.001). This novel stroke risk score performed better than existing CHADS2/ CHA2DS2-VASc scores and showed improvement in predicting first-ever ischemic stroke in HFrEF patients.

Changes in Apparent Diffusion Coefficient as Surrogate Marker for Changes in Ki-67 Index Due to Neoadjuvant Chemotherapy in Patients with Invasive Breast Cancer.

RATIONALE AND OBJECTIVES: To evaluate possible correlation between changes in apparent diffusion coefficient (ADC) and Ki-67 index as a result of neoadjuvant chemotherapy (NAC) in patients with invasive breast cancer. METHODS AND MATERIALS: Between February 2016 and October 2017, 87 patients with breast cancer underwent diffusion-weighted magnetic resonance imaging (b = 0 and 800 sec/mm2) before and after NAC. ADC and tumor diameter before and after NAC were compared to the Ki-67 index determined from biopsy or surgical specimens. RESULTS: Ki-67 index did not correlate significantly with ADC before NAC (p = 0.862) or afterwards (p = 0.292), nor did it correlate with tumor diameter before (p = 0.545) or afterwards (p = 0.478). However, change in ADC as a result of NAC correlated inversely with change in Ki-67 index (r = -0.326, p = 0.002). The percentage change in Ki-67 index did not correlate with the percentage change in ADC (p = 0.404). Similarly, the change in Ki-67 index or percentage change in that index did not correlate with the change in tumor diameter (p = 0.075) or percentage change in tumor diameter (p = 0.233). CONCLUSION: Comparison of pre- and post-NAC ADC can be used to estimate the change in Ki-67 index in patients with invasive breast cancer.

Breast cancer in postmenopausal women is associated with an altered gut metagenome.

BACKGROUND: Increasing evidence suggests that gut microbiota play a role in the pathogenesis of breast cancer. The composition and functional capacity of gut microbiota associated with breast cancer have not been studied systematically. METHODS: We performed a comprehensive shotgun metagenomic analysis of 18 premenopausal breast cancer patients, 25 premenopausal healthy controls, 44 postmenopausal breast cancer patients, and 46 postmenopausal healthy controls. RESULTS: Microbial diversity was higher in breast cancer patients than in controls. Relative species abundance in gut microbiota did not differ significantly between premenopausal breast cancer patients and premenopausal controls. In contrast, relative abundance of 45 species differed significantly between postmenopausal patients and postmenopausal controls: 38 species were enriched in postmenopausal patients, including Escherichia coli, Klebsiella sp_1_1_55, Prevotella amnii, Enterococcus gallinarum, Actinomyces sp. HPA0247, Shewanella putrefaciens, and Erwinia amylovora, and 7 species were less abundant in postmenopausal patients, including Eubacterium eligens and Lactobacillus vaginalis. Acinetobacter radioresistens and Enterococcus gallinarum were positively but weakly associated with expression of high-sensitivity C-reactive protein; Shewanella putrefaciens and Erwinia amylovora were positively but weakly associated with estradiol levels. Actinomyces sp. HPA0247 negatively but weakly correlated with CD3+CD8+ T cell numbers. Further characterization of metagenome functional capacity indicated that the gut metagenomes of postmenopausal breast cancer patients were enriched in genes encoding lipopolysaccharide biosynthesis, iron complex transport system, PTS system, secretion system, and beta-oxidation. CONCLUSION: The composition and functions of the gut microbial community differ between postmenopausal breast cancer patients and healthy controls. The gut microbiota may regulate or respond to host immunity and metabolic balance. Thus, while cause and effect cannot be determined, there is a reproducible change in the microbiota of treatment-naive patients relative to matched controls.

Aberrant expression of RSK4 in breast cancer and its role in the regulation of tumorigenicity.

Breast cancer is the most frequently diagnosed cancer in both more and less economically developed countries and remains the leading cause of cancer-related death in women worldwide. In this study, to explore the expression and pathological role of RSK4 in breast cancer progression, we demonstrated that RSK4 expression was significantly decreased in breast cancer cells and tissues, and the overexpression of RSK4 in MDA­MB­231 cells inhibited cell migration and invasion. In a mouse model experiment, overexpression of RSK4 in mice further confirmed its critical role in regulating breast cancer tumorigenicity. The regulatory role of RSK4 in breast cancer development was mediated by AKT and extracellular signal­regulated kinase (ERK) signaling pathways and the expression of RSK4 was altered by DNA methylation in promoter regions. These results provide important insight into the role of RSK4 in cancerogenesis and may help to improve the prevention, diagnosis and treatment of breast cancer.

Frequent epigenetic inactivation of RSK4 by promoter methylation in cancerous and non-cancerous tissues of breast cancer.

Breast cancer is one of the most common cancers and is the second leading cause of cancer-related death in women worldwide. Ribosomal s6 kinase4 (RSK4) is a potential tumor suppressor in multiple cancers, while its role in breast cancer is largely unknown. Our study here aimed to explore the relationship between RSK4 expression with the clinicopathologic characteristics and the promoter methylation status of RSK4. Real-time PCR and bisulfite sequencing PCR were, respectively, used to detect the expression difference of RSK4 mRNA and RSK4 methylation in the 49 breast cancer and paired non-cancerous samples. The associations of RSK4 expression and methylation status with the clinicopathologic characteristics were analyzed. In the 49 breast cancer patients' specimens, RSK4 mRNA expression was found to be significantly decreased in most of breast cancer tissues compared with paired non-cancerous tissues (p = 0.002), which was largely due to the promoter hypermethylation (p = 0.005). Frequency of RSK4 promoter methylation in breast cancers was significantly higher than paired non-cancerous tissues (p = 0.009); RSK4 methylation was not associated with all clinicopathological features. The silencing of RSK4 due to promoter hypermethylation is a frequent event in breast cancer. The majority of cancers have a higher level of methylation status when compared with non-cancerous tissues. RSK4 may be a valuable biomarker for the study of breast cancer carcinogenesis and progression.