The association between breast cancer and S100P methylation in peripheral blood by multicenter case-control studies

IL21R hypomethylation as a biomarker for distinguishing benign and malignant breast tumours

Some benign and malignant breast tumours are similar in pathological morphology, which are difficult to be distinguished in clinical diagnosis. In this study, we intended to explore novel biomarkers for differential diagnosis of benign and malignant breast tumours. Methylation EPIC 850K beadchip and RNA-sequencing were used to analyse 29 tissue samples from patients with early-stage breast cancer (BC) and benign breast tumours for differently methylated and expressed genes. The altered methylation of IL21R was semi-quantitatively validated in an independent study with 566 tissue samples (279 BC vs. 287 benign breast tumours) using mass spectrometry. Binary logistic regression analysis was performed to evaluate the association between IL21R methylation and BC. BC-associated IL21R hypomethylation and overexpression were identified in the discovery round. In the validation round, BC patients presented significant IL21R hypomethylation compared to women with benign breast tumours (ORs ≥1.29 per-10% methylation, p-values ≤ 5.69E-14), and this hypomethylation was even enhanced in BC patients with ER-negative and PR-negative tumours as well as with triple-negative tumours. The methylation of IL21R showed efficient discriminatory power to distinguish benign breast tumours from BC (area under curve (AUC) = 0.88), and especially from ER-negative BC (AUC = 0.95), PR-negative BC (AUC = 0.93) and triple-negative BC (AUC = 0.96). We disclosed significant IL21R hypomethylation in patients with BC compared to women with benign breast tumours, and revealed the somatic change of DNA methylation could be a potential biomarker for molecular pathology of BC.

Hypermethylation of the Gene Body in SRCIN1 Is Involved in Breast Cancer Cell Proliferation and Is a Potential Blood-Based Biomarker for Early Detection and a Poor Prognosis

Breast cancer is a leading cause of cancer mortality in women worldwide. Using the Infinium MethylationEPIC BeadChip, we analyzed plasma sample methylation to identify the SRCIN1 gene in breast cancer patients. We assessed SRCIN1-related roles and pathways for their biomarker potential. To verify the methylation status, quantitative methylation-specific PCR (qMSP) was performed on genomic DNA and circulating cell-free DNA samples, and mRNA expression analysis was performed using RT‒qPCR. The results were validated in a Western population; for this analysis, the samples included plasma samples from breast cancer patients from the USA and from The Cancer Genome Atlas (TCGA) cohort. To study the SRCIN1 pathway, we conducted cell viability assays, gene manipulation and RNA sequencing. SRCIN1 hypermethylation was identified in 61.8% of breast cancer tissues from Taiwanese patients, exhibiting specificity to this malignancy. Furthermore, its presence correlated significantly with unfavorable 5-year overall survival outcomes. The levels of methylated SRCIN1 in the blood of patients from Taiwan and the USA correlated with the stage of breast cancer. The proportion of patients with high methylation levels increased from 0% in healthy individuals to 63.6% in Stage 0, 80% in Stage I and 82.6% in Stage II, with a sensitivity of 78.5%, an accuracy of 90.3% and a specificity of 100%. SRCIN1 hypermethylation was significantly correlated with increased SRCIN1 mRNA expression (p < 0.001). Knockdown of SRCIN1 decreased the viability of breast cancer cells. SRCIN1 silencing resulted in the downregulation of ESR1, BCL2 and various cyclin protein expressions. SRCIN1 hypermethylation in the blood may serve as a noninvasive biomarker, facilitating early detection and prognosis evaluation, and SRCIN1-targeted therapies could be used in combination regimens for breast cancer patients.

Blood FOLR3 methylation dysregulations and heterogeneity in non-small lung cancer highlight its strong associations with lung squamous carcinoma

BACKGROUND

Non-small cell lung cancer (NSCLC) accounts for the vast majority of lung cancers. Early detection is crucial to reduce lung cancer-related mortality. Aberrant DNA methylation occurs early during carcinogenesis and can be detected in blood. It is essential to investigate the dysregulated blood methylation markers for early diagnosis of NSCLC.

METHODS

NSCLC-associated methylation gene folate receptor gamma (FOLR3) was selected from an Illumina 850K array analysis of peripheral blood samples. Mass spectrometry was used for validation in two independent case-control studies (validation I: n = 2548; validation II: n = 3866). Patients with lung squamous carcinoma (LUSC) or lung adenocarcinoma (LUAD), normal controls (NCs) and benign pulmonary nodule (BPN) cases were included. FOLR3 methylations were compared among different populations. Their associations with NSCLC clinical features were investigated. Receiver operating characteristic analyses, Kruskal-Wallis test, Wilcoxon test, logistics regression analysis and nomogram analysis were performed.

RESULTS

Two CpG sites (CpG_1 and CpG_2) of FOLR3 was significantly lower methylated in NSCLC patients than NCs in the discovery round. In the two validations, both LUSC and LUAD patients presented significant FOLR3 hypomethylations. LUSC patients were highlighted to have significantly lower methylation levels of CpG_1 and CpG_2 than BPN cases and LUAD patients. Both in the two validations, CpG_1 methylation and CpG_2 methylation could discriminate LUSC from NCs well, with areas under the curve (AUCs) of 0.818 and 0.832 in validation I, and 0.789 and 0.780 in validation II. They could also differentiate LUAD from NCs, but with lower efficiency. CpG_1 and CpG_2 methylations could also discriminate LUSC from BPNs well individually in the two validations. With the combined dataset of two validations, the independent associations of age, gender, and FOLR3 methylation with LUSC and LUAD risk were shown and the age-gender-CpG_1 signature could discriminate LUSC and LUAD from NCs and BPNs, with higher efficiency for LUSC.

CONCLUSIONS

Blood-based FOLR3 hypomethylation was shown in LUSC and LUAD. FOLR3 methylation heterogeneity between LUSC and LUAD highlighted its stronger associations with LUSC. FOLR3 methylation and the age-gender-CpG_1 signature might be novel diagnostic markers for the early detection of NSCLC, especially for LUSC.

RUNX1 methylation as a cancer biomarker in differentiating papillary thyroid cancer from benign thyroid nodules

Aim: It remains a challenge to accurately identify malignancy of thyroid nodules when biopsy is indeterminate. The authors aimed to investigate the abnormal DNA methylation signatures in papillary thyroid cancer (PTC) compared with benign thyroid nodules (BTNs). Methods: The authors performed genome profiling by 850K array and RNA sequencing in early-stage PTC and BTN tissue samples. The identified gene was validated in two independent case-control studies using mass spectrometry. Results: Hypomethylation of RUNX1 in PTC was identified and verified (all odds ratios: ≥1.50). RUNX1 methylation achieved good accuracy in differentiating early-stage PTC from BTNs, especially for younger women. Conclusion: The authors disclosed a significant association between RUNX1 hypomethylation and PTC, suggesting RUNX1 methylation as a potential biomarker for companion diagnosis of malignant thyroid nodules.

DNA Methylation Status of HYAL1 in Malignant and Benign Thyroid Nodules

Differentiation between benign and malignant thyroid nodules has been a challenge in clinical practice. Exploring a novel biomarker to determine the malignancy of thyroid nodules has important implications. We semi-quantitatively determined the DNA methylation levels of four CpG sites located at the gene body of HYAL1 in formalin-fixed paraffin-embedded (FFPE) tissue samples from 190 early-stage papillary thyroid cancer (PTC) cases and 190 age- and gender-matched subjects with benign thyroid nodule (BTN). HYAL1 expression was evaluated by immunohistochemical (IHC) staining in another cohort of 55 PTC and 55 matched BTN cases. Covariates-adjusted odds ratios (ORs) for 10% increased methylation were calculated by binary logistic regression. A 165 bp amplicon covering four CpG sites at the second exon of HYAL1 gene was designed. After adjusted for all covariates, higher methylation level of HYAL1_CpG_3,4 in the FFPE tissue was associated with PTC (OR per 10% increased methylation=1.53, p=0.025), even with stage І PTC (OR per 10% increased methylation=1.58, p=0.021). Hypermethylation of HYAL1_CpG_3,4 had a significant association with early-stage PTC in the females (OR per 10% increased methylation=1.60, p=0.028) rather than in the males. Besides, we found the higher expression of HYAL1 protein in PTC than that in BTN patients (IHC score: 2.3 vs. 0.5, p=1.00E-06). Our study suggested altered methylation and expression of HYAL1 could be a novel and potential biomarker in distinguishing malignant and benign thyroid nodules.

Hypomethylation of DYRK4 in peripheral blood is associated with increased lung cancer risk

Lung cancer (LC) is the leading cause of cancer-related deaths worldwide. It is urgent to identify new biomarkers for the early detection of LC. DNA methylation in peripheral blood has been reported to be associated with cancers. We conducted two independent case-control studies and a nested case-control study (168 LC cases and 167 controls in study Ⅰ, 677 LC cases and 833 controls in study Ⅱ, 147 precancers and 21 controls in the nested case-control study). The methylation levels of DYRK4 CpG sites were measured using mass spectrometry and their correlations with LC were analyzed by logistic regression and nonparametric tests. Bonferroni correction was used for the multiple comparisons. LC-related decreased DYRK4 methylation was discovered in Study I and validated in Study II (the odds ratios [ORs] for the lowest vs. highest quartile of all three DYRK4 CpG sites ranged from 1.64 to 2.09, all p < 0.001). Combining the two studies, hypomethylation of DYRK4 was observed in stage I cases (ORs per -10% methylation ranged from 1.16 to 1.38, all p < 5.9E-04), and could be enhanced by male gender (ORs ranged from 1.77 to 4.17 via interquartile analyses, all p < 0.017). Hypomethylation of DYRK4_A_CpG_2 was significantly correlated with tumor size, length, and stage (p = 0.034, 0.002, and 0.002, respectively) in LC cases. Our study disclosed the association between DYRK4 hypomethylation in peripheral blood and LC, suggesting the feasibility of blood-based DNA methylation as new biomarker for LC detection.

Hypomethylation of ABCG1 in peripheral blood as a potential marker for the detection of coronary heart disease

BACKGROUND

Novel molecular biomarkers for the risk assessment and early detection of coronary heart disease (CHD) are urgently needed for disease prevention. Altered methylation of ATP-binding cassette subfamily G member 1 (ABCG1) has been implicated in CHD but was mostly studied in Caucasians. Exploring the potential relationship between ABCG1 methylation in blood and CHD among the Chinese population would yield valuable insights.

METHODS

Peripheral blood samples were obtained from a case-control study (287 CHD patients vs. 277 controls) and a prospective nested case-control study (171 CHD patients and 197 matched controls). DNA extraction and bisulfite-specific PCR amplification techniques were employed for sample processing. Quantitative assessment of methylation levels was conducted using mass spectrometry. Statistical analyses involved the utilization of logistic regression and nonparametric tests.

RESULTS

We found hypomethylation of ABCG1 in whole blood was associated with the risk of CHD in both studies, which was enhanced in heart failure (HF) patients, female and younger subjects. When combined with baseline characteristics, altered ABCG1 methylation showed improved predictive effect for differentiating CHD cases, ischemic cardiomyopathy (ICM) cases, younger than 60 years CHD cases, and female CHD cases from healthy controls (area under the curve (AUC) = 0.68, 0.71, 0.74, and 0.73, respectively).

CONCLUSIONS

We demonstrated a robust link between ABCG1 hypomethylation in whole blood and CHD risk in the Chinese population and provided novel evidence indicating that aberrant ABCG1 methylation in peripheral blood can serve as an early detection biomarker for CHD patients.

Buffy coat signatures of breast cancer risk in a prospective cohort study

BACKGROUND

Epigenetic alterations are a near-universal feature of human malignancy and have been detected in malignant cells as well as in easily accessible specimens such as blood and urine. These findings offer promising applications in cancer detection, subtyping, and treatment monitoring. However, much of the current evidence is based on findings in retrospective studies and may reflect epigenetic patterns that have already been influenced by the onset of the disease.

METHODS

Studying breast cancer, we established genome-scale DNA methylation profiles of prospectively collected buffy coat samples (n = 702) from a case-control study nested within the EPIC-Heidelberg cohort using reduced representation bisulphite sequencing (RRBS).

RESULTS

We observed cancer-specific DNA methylation events in buffy coat samples. Increased DNA methylation in genomic regions associated with SURF6 and REXO1/CTB31O20.3 was linked to the length of time to diagnosis in the prospectively collected buffy coat DNA from individuals who subsequently developed breast cancer. Using machine learning methods, we piloted a DNA methylation-based classifier that predicted case-control status in a held-out validation set with 76.5% accuracy, in some cases up to 15 years before clinical diagnosis of the disease.

CONCLUSIONS

Taken together, our findings suggest a model of gradual accumulation of cancer-associated DNA methylation patterns in peripheral blood, which may be detected long before clinical manifestation of cancer. Such changes may provide useful markers for risk stratification and, ultimately, personalized cancer prevention.

The association between CTSZ methylation in peripheral blood and breast cancer in Chinese women

Purpose

Previous studies have shown that DNA methylation in peripheral blood may be associated with breast cancer (BC). To explore the association between the methylation level of the Cathepsin Z (CTSZ) gene in peripheral blood and BC, we conducted a case-control study in the Chinese population.

Methods

Peripheral blood samples were collected from 567 BC cases, 635 healthy controls, and 303 benign breast disease (BBD) cases. DNA extraction and bisulfite-specific PCR amplification were performed for all samples. The methylation levels of seven sites of the CTSZ gene were quantitatively determined by Mass spectrometry. The odds ratios (ORs) of CpG sites were evaluated for BC risk using per 10% reduction and quartiles analyses by logistic regression.

Results

Our analysis showed that five out of the seven CpG sites exhibited significant associations with hypomethylation of CTSZ and BC, compared to healthy controls. The highest OR was for Q2 of CTSZ_CpG_1 (OR: 1.62, P=0.006), particularly for early-stage breast cancer in the case of per 10% reduction of CTSZ_CpG_1 (OR: 1.20, P=0.003). We also found that per 10% reduction of CTSZ_CpG_5 (OR: 1.39, P=0.004) and CTSZ_CpG_7,8 (OR: 1.35, P=0.005) were associated with increased BC risk. Our study also revealed that four out of seven CpG sites were linked to increased BC risk in women under 50 years of age, compared to healthy controls. The highest OR was for per 10% reduction of CTSZ_CpG_1 (OR: 1.47, P<0.001). Additionally, we found that BC exhibited lower methylation levels than BBD at CTSZ_CpG_4 (OR for Q1: 2.18, P<0.001) and CTSZ_CpG_7,8 (OR for Q1: 2.01, P=0.001). Furthermore, we observed a correlation between methylation levels and tumor stage, ER, and HER2 status in BC patients.

Conclusion

Overall, our findings suggest that altered CTSZ methylation levels in peripheral blood may be associated with breast cancer, particularly in young women, and may serve as a potential biomarker for early-stage BC.

New Association Between Diabetes Mellitus and Pancreatic Cancer

BACKGROUND

Diabetes mellitus is a global issue that has affected the lives of many people all over the world. This disorder, which is also called the mother of all diseases, possesses high pathogenicity and results in the emergence of many disorders. One of the known correlated diseases is pancreatic cancer which can be accompanied by diabetes mellitus. Therefore, finding the association between these diseases and common genes is urgent.

OBJECTIVE

In this study, in order to survey the relationship between diabetes mellitus and pancreatic cancer, the common genes of these disorders were analyzed by bioinformatics tools.

METHODS

For this purpose, we screened 17 shared genes from microarray data downloaded from the Gene Expression Omnibus (GEO) database. In addition, the relationship between identified genes was constructed by STRING and DAVID tools.

RESULTS

In total, 112 genes were identified to be differentially expressed. Among these, 17 genes were found to be common, including two genes that were down-regulated and others that were upregulated. Other analyses showed that most of the genes were enriched in Vibrio cholera infection and the mTOR signaling pathway. The biological processes of such genes included oxygen and gas transport, phagosome acidification, and GTPase activity.

CONCLUSION

In this study, 17 common genes that had not previously been considered in diabetes and pancreatic cancer were screened, which can be further considered for clinical approaches and in vitro studies.

HTRA1 methylation in peripheral blood as a potential marker for the preclinical detection of stroke: a case-control study and a prospective nested case-control study

BACKGROUND

Stroke is the leading cause of mortality in China. DNA methylation has essential roles in multiple diseases, but its association with stroke was barely studied. We hereby explored the association between blood-based HTRA serine protease 1 (HTRA1) methylation and the risk of stroke.

RESULTS

The association was discovered in a hospital-based case-control study (cases/controls = 190:190) and further validated in a prospective nested case-control study including 139 cases who developed stroke within 2 years after recruitment and 144 matched stroke-free controls. We observed stroke-related altered HTRA1 methylation and expression in both case-control study and prospective study. This blood-based HTRA1 methylation was associated with stroke independently from the known risk factors and mostly affected the older population. The prospective results further showed that the altered HTRA1 methylation was detectable 2 years before the clinical determination of stroke and became more robust with increased discriminatory power for stroke along with time when combined with other known stroke-related variables [onset time ≤ 1 year: area under the curve (AUC) = 0.76].

CONCLUSIONS

In our study, altered HTRA1 methylation was associated with stroke at clinical and preclinical stages and thus may provide a potential biomarker in the blood for the risk evaluation and preclinical detection of stroke.

The association between ACTB methylation in peripheral blood and coronary heart disease in a case-control study

Background

Coronary heart disease (CHD) brings a heavy burden to society worldwide. Novel and minimally invasive biomarkers for the risk evaluation of CHD are urgently needed. Previous study has revealed that blood-based hypomethylation of β-actin (ACTB) was associated with increased risk of stroke, but not reported in CHD yet.

Objectives

We aimed to explore the association between blood-based ACTB methylation and the risk of CHD in a case-control study in the Chinese population.

Methods

The methylation level of ACTB was quantitatively determined by mass spectrometry in 281 CHD patients and 272 controls. The association between ACTB methylation and CHD risk was estimated by logistic regression analyses adjusted for possible confounding effects.

Results

We found a significant association between hypermethylation of ACTB in peripheral blood and increased risk of CHD (odds ratios (ORs) per +10% methylation: 1.19–1.45, p < 0.013 for nine out of thirteen CpG sites), especially in male subjects and heart failure (HF) patients (ORs per +10% methylation: 1.20–1.43, 1.38–1.46; p < 0.030, 1.52 × 10⁻⁴, respectively). Hypermethylation of ACTB_CpG_2.3, ACTB_CpG_7.8, and ACTB_CpG_9.10 was observed in the CHD patients with minor to medium cardiac function impairment (NYHA I&II CHD cases) (ORs per +10% methylation: 1.38–1.44; p < 0.001). The combination of ACTB_CpG_2.3, ACTB_CpG_7.8, and ACTB_CpG_9.10 methylation levels could efficiently discriminate CHD cases, male CHD patients, HF and NYHA I&II CHD patients from controls (area under curve (AUC) = 0.75, 0.74, 0.73, and 0.77, respectively).

Conclusions

Our study reveals a strong association between blood-based ACTB hypermethylation and CHD risk. The combination of ACTB methylation and conventional risk factors might provide a novel strategy to improve risk assessment of CHD.

The association between DNA methylation of 6p21.33 and AHRR in blood and coronary heart disease in Chinese population

BACKGROUND

Early detection could significantly improve the prognosis of coronary heart disease (CHD). In-invitro diagnostic technique may provide a solution when sufficient biomarkers could be identified. Pertinent associations between blood-based aberrant DNA methylation and smoking, the pathogenesis of atherosclerosis, and CHD have been robustly demonstrated and replicated, but that studies in Chinese populations are rare. The blood-based methylation of aryl-hydrocarbon receptor repressor (AHRR) cg05575921 and 6p21.33 cg06126421 has been associated with cardiovascular mortality in Caucasians. Here, we aim to investigate whether the AHRR and 6p21.33 methylation in the blood is associated with CHD in the Chinese population.

METHODS

In this case-control study, 180 CHD patients recruited at their first registration in our study center, and 184 controls randomly selected from the people who participated in the annual health examination were enrolled. Methylation intensities of 19 CpG sites, including AHRR cg05575921, 6p21.33 cg06126421, and their flanking CpG sites, were quantified by mass spectrometry. The association between methylation intensities and CHD was estimated by logistic regression analyses adjusted for covariant.

RESULTS

Compared to the controls, lower methylation of 6p21.33_CpG_4.5/cg06126421 was independently associated with increased odds of being a CHD patient (OR per - 10% methylation = 1.42 after adjustment for age, gender, and batch effect; p = 0.032 by multiple testing corrections). No association between blood-based AHRR methylation and CHD was found.

CONCLUSIONS

6p21.33 methylation exhibits a significant association with CHD. The combination of 6p21.33 methylation and conventional risk factors might be an intermediate step towards the early detection of CHD.

The influence of blood sample processing on blood-based DNA methylation signatures

Stability is crucial for the clinical applicable biomarker such as DNA methylation profiles. However, the influence of various blood processing on the DNA methylation signatures have been barely studied. Here, we systematically evaluated the impact of temporary storage and frozen and thaw on the levels of DNA methylation. The methylation intensities of 13 CpG loci from 53 individuals (42 healthy participants and 11 lung cancer patients) whose blood samples were processed by up to 14 various protocols were quantitatively determined by the mass spectrometry, obtaining more than 8,000 quantitative data. We disclosed a trend of accumulatively increased DNA methylation along with time when the blood from healthy people were stored for up to 96 hours at room temperature (RT), whereas the storage at 4℃ had much weaker effects or no impact. On the contrary, the methylation patterns in the blood of lung cancer patients were more stable at both RT and 4℃ even for 96 hours. Multiple cycles of frozen and thaw could result in demethylation, but was more significant to the blood than to the extracted DNA. Our study indicated that the blood processing in vitro could influence the DNA methylation signatures and introduce unexpected biases.

Global Increase in Breast Cancer Incidence: Risk Factors and Preventive Measures

Breast cancer is a global cause for concern owing to its high incidence around the world. The alarming increase in breast cancer cases emphasizes the management of disease at multiple levels. The management should start from the beginning that includes stringent cancer screening or cancer registry to effective diagnostic and treatment strategies. Breast cancer is highly heterogeneous at morphology as well as molecular levels and needs different therapeutic regimens based on the molecular subtype. Breast cancer patients with respective subtype have different clinical outcome prognoses. Breast cancer heterogeneity emphasizes the advanced molecular testing that will help on-time diagnosis and improved survival. Emerging fields such as liquid biopsy and artificial intelligence would help to under the complexity of breast cancer disease and decide the therapeutic regimen that helps in breast cancer management. In this review, we have discussed various risk factors and advanced technology available for breast cancer diagnosis to combat the worst breast cancer status and areas that need to be focused for the better management of breast cancer.

B3GNT3 as a prognostic biomarker and correlation with immune cell infiltration in lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common malignant cancer in humans and because of low long-term survival rates, exploration of the molecular mechanisms underlying its progression, as well as novel prognostic predictors, is urgently needed. B3GNT3, a type II transmembrane protein located in the Golgi apparatus, is essential for forming extended core 1 oligosaccharides and is reportedly involved in malignant transformation.

Methods

The Cancer Genome Atlas (TCGA) and GSE68465 were used to analyze the expression of B3GNT3 in LUAD and normal tissues and overall survival. Real time quantitative polymerase chain reaction (qPCR) and western blot were conducted to measure the mRNA and protein levels of B3GNT3, respectively. Functional enrichment of differentially expressed genes was explored using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses. We performed univariate and multivariate Cox regression analyses and a meta-analysis to reveal an independent factor for LUAD. We evaluated the correlation between immune infiltration levels and cumulative survival in the TIMER database. The correlation between B3GNT3 and immune cell infiltration was assessed via Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT). The association of DNA methylation of B3GNT3 and prognosis was determined. A nomogram that incorporated expression and clinical features was additionally built for prognostic prediction. Cell proliferation, cloning, and invasion were conducted to validate the roles of B3GNT3 in LUAD.

Results

B3GNT3 was more highly expressed in LUAD tissues than in normal lung tissues, consistent with the mRNA and protein levels in LUAD cells. B3GNT3 was an independent factor for LUAD. Moreover, the levels of B3GNT3 were related to immune cell infiltration in LUAD microenvironments. DNA methylation of B3GNT3 correlated with the mRNA of B3GNT and overall survival of LUAD patients. The expression of B3GNT3 was highly valuable for the prediction of diagnosis. Knockdown of B3GNT3 inhibited LUAD cell viability and cloning ability, and hindered invasion.

Conclusions

B3GNT3 was highly associated with immune cell infiltration, acting as an important biomarker for the prognosis and diagnosis of LUAD.

Breast Cancer; Discovery of Novel Diagnostic Biomarkers, Drug Resistance, and Therapeutic Implications

Breast cancer is the second most reported cancer in women with high mortality causing millions of cancer-related deaths annually. Early detection of breast cancer intensifies the struggle towards discovering, developing, and optimizing diagnostic biomarkers that can improve its prognosis and therapeutic outcomes. Breast cancer-associated biomarkers comprise macromolecules, such as nucleic acid (DNA/RNA), proteins, and intact cells. Advancements in molecular technologies have identified all types of biomarkers that are exclusively studied for diagnostic, prognostic, drug resistance, and therapeutic implications. Identifying biomarkers may solve the problem of drug resistance which is a challenging obstacle in breast cancer treatment. Dysregulation of non-coding RNAs including circular RNAs (circRNAs) and microRNAs (miRNAs) initiates and progresses breast cancer. The circulating multiple miRNA profiles promise better diagnostic and prognostic performance and sensitivity than individual miRNAs. The high stability and existence of circRNAs in body fluids make them a promising new diagnostic biomarker. Many therapeutic-based novels targeting agents have been identified, including ESR1 mutation (DNA mutations), Oligonucleotide analogs and antagonists (miRNA), poly (ADP-ribose) polymerase (PARP) in BRCA mutations, CDK4/6 (cell cycle regulating factor initiates tumor progression), Androgen receptor (a steroid hormone receptor), that have entered clinical validation procedure. In this review, we summarize the role of novel breast cancer diagnostic biomarkers, drug resistance, and therapeutic implications for breast cancer.

[Detection of DNA methylation of HYAL2 gene for differentiating malignant from benign thyroid tumors]

OBJECTIVE

To assess the value of DNA methylation level of HYAL2 gene as a molecular marker for differential diagnosis of malignant and benign thyroid tumors.

METHODS

DNA methylation of HYAL2 gene in tissue specimens of 190 patients with papillary thyroid cancer (PTC) and 190 age- and gender-matched patients with benign thyroid tumors was examined by mass spectrometry, and the protein expression of HYAL2 was detected immunohistochemically for another 55 pairs of patients. Logistic regression analysis was performed to calculate the odds ratio (OR) and evaluate the correlation of per 10% reduction in DNA methylation with PTC. Receiver operating characteristic (ROC) curve analysis was performed and the area under curve (AUC) was calculated to assess the predictive value of alterations in HYAL2 methylation.

RESULTS

Hypomethylation of HYAL2_CpG_3 was significantly correlated with early-stage PTC (OR=1.51, P=0.001), even in stage I cancer (OR=1.42, P=0.007). Age-stratified analysis revealed a significantly stronger correlation between increased HYAL2_CpG_ 3 methylation and early-stage PTC in patients below 50 years than in those older than 50 years (OR: 1.89 vs 1.37, P < 0.05); ROC analysis also showed a larger AUC of 0.787 in younger patients. The results of immunohistochemistry showed that patients with PTC had significantly higher protein expressions of HYAL2 than patients with benign tumors.

CONCLUSION

The alterations of DNA methylation level of HYAL2 gene is significantly correlated with early-stage PTC, suggesting the value of DNA methylation level as a potential biomarker for differentiation of malignant from benign thyroid tumors.

FYB methylation in peripheral blood as a potential marker for the early-stage lung cancer: a case-control study in Chinese population

BACKGROUND

Lung cancer (LC) is the leading cause of cancer-related morbidity and mortality in China. Exploring novel biomarkers for the early detection of LC is important.

MATERIALS AND METHODS

We quantified DNA methylation levels of three CpG sites of FYB gene in peripheral blood in 163 early-stage LC cases (88.3% at stage I) and 187 age- and gender-matched healthy controls. Covariates-adjusted odds ratios (ORs) for -10% methylation were calculated by binary logistic regression.

RESULTS

With multiple testing corrections, hypomethylation of FYB_CpG_4 was significantly associated with LC (OR = 2.04, p = 4.50E-04) even with LC at stage I (OR = 1.41, p = 0.003) without obvious bias between genders, but it mainly affected the subjects older than 55 years (OR = 2.04, p = 0.015). Hypomethylation of FYB_CpG_2 was also associated with LC, but only for the males (OR = 1.76, p = 0.018). FYB_CpG_3 methylation had no association with LC, but interestingly its methylation level in the males was only half of that in the females.

DISCUSSION AND CONCLUSIONS

We proposed a novel association between blood-based abnormal FYB methylation and very early-stage LC. The age- and gender-related DNA methylation patterns also revealed the diversity and precision of epigenetic regulations.

RPTOR methylation in the peripheral blood and breast cancer in the Chinese population

BACKGROUND

Altered regulatory-associated protein of mTOR, complex 1 (RPTOR) methylation levels in peripheral blood was originally discovered as breast cancer (BC)-associated risk factor in Caucasians.

OBJECTIVE

To explore the relationship between RPTOR methylation and BC in the Chinese population, we conducted two independent case-control studies.

METHODS

Peripheral blood samples were collected from a total of 333 sporadic BC cases and 378 healthy female controls for the DNA extraction and bisulfite-specific PCR amplification. Mass spectrometry was applied to quantitatively measure the levels of methylation. The logistic regression, Spearman's rank correlation, and Non-parametric tests were used for the statistical analyses.

RESULTS

In our study, we found an association between BC and RPTOR_CpG_4 hypomethylation in the general population (per-10% of methylation, OR 1.29, P = 0.012), and a weak association between BC and RPTOR_CpG_8 hypomethylation in the women with older age (per-10% of methylation, OR 2.34, P = 0.006). We also identified age as a confounder for the change of RPTOR methylation patterns, especially at RPTOR_CpG_4, which represented differential methylation comparing age groups especially in the BC cases (age < 50 years vs age ≥ 50 years by Mann-Whitney U test, P < 0.0001 for BC cases and P = 0.079 for controls).

CONCLUSION

Our study validated the association between hypomethylation of RPTOR and BC risk in the Chinese population also with weak effect and mostly for postmenopausal women. In addition, our findings provided novel insight for the regulation of DNA methylation upon aging or the change of hormone levels.

The Association Between PNPLA2 Methylation in Peripheral Blood and Early-Stage Lung Cancer in a Case-Control Study

Purpose

Lung cancer (LC) brings great burden to the society worldwide. Exploring novel biomarkers in vitro for the early detection of LC would be of great importance.

Patients and Methods

We measured DNA methylation levels of 21 CpG sites within Patatin-like phospholipase domain containing 2 (PNPLA2) gene in the peripheral blood of 168 early-stage LC cases (94.0% LC at stage I) and 187 age- and gender-matched cancer-free controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression adjusted for covariates. Non-parametric tests were applied for the comparisons of stratified groups.

Results

Hypomethylation of PNPLA2_CpG_8,10 and hypermethylation of PNPLA2_CpG_9 were correlated to the early-stage LC with the ORs of 1.44 (95% CI: 1.06–1.96, P = 0.018) and 0.82 (95% CI: 0.69–0.98, P = 0.029), respectively. The associations were still significant for the very early-stage LC patients (stage I). Further gender- and age-stratified analyses indicated that the association between hypomethylation of PNPLA2_CpG_8,10 and LC existed only in females and in subjects younger than 55 years. In addition, the association between LC and hypermethylation of PNPLA2_CpG_6 and PNPLA2_CpG_9 was also observed in the younger population.

Conclusion

Taken together, our study has proved the hypothesis that the altered methylation in the peripheral blood may be correlated with the burden of cancer at an early stage. Here, we find a novel association between blood-based aberrant PNPLA2 methylation and LC at a very early stage and particularly for women at a younger age.

[Peripheral blood EMR3 gene methylation level is correlated with breast cancer in Chinese women]

OBJECTIVE

To explore the association of methylation levels of C19orf57, MAP9, EMR3, NEK6 and PCOLCE2 genes in peripheral blood with breast cancer (BC) in Chinese women.

METHODS

We collected peripheral blood samples from 258 early-stage BC patients and 272 healthy women. Agena matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to quantitatively measure the methylation levels of CpG sites in the genes. The association between DNA methylation and BC was analyzed using a logistic regression model adjusted for covariants. Spearman's correlation analysis was performed to analyze the association between the gene methylation levels and age. The methylation levels of the genes in the BC patients with different clinical characteristics were investigated using non-parametric tests.

RESULTS

In stead of EMR3 gene hypermethylation as found in BC patients as found in the Caucasian population, EMR3 gene hypomethylation was found to correlate with BC in Chinese women, but this correlation was significant only in women beyond the age of 50 years (for every 10% reduction of the methylation level, EMR3_CpG_1: OR=1.40; EMR3_CpG_2: OR=2.31; EMR3_CpG_3: OR=2.76, P < 0.05). EMR3 methylation was not or was only weakly correlated with tumor stage, size, lymphatic metastasis, ER, PR, HER2, or Ki67. Our data did not show a correlation between C19orf57 methylation and BC.

CONCLUSION

Peripheral blood EMR3 gene hypomethylation is associated with BC in Chinese women, especially in those at an old age and in postmenopausal women.

ACTB Methylation in Blood as a Potential Marker for the Pre-clinical Detection of Stroke: A Prospective Nested Case-Control Study

Background

Stroke is the second leading cause of death worldwide. If risk of stroke could be evaluated early or even at a preclinical stage, the mortality rate could be reduced dramatically. However, the identified genetic factors only account for 5-10% of the risk of stroke. Studies on the risk factors of stroke are urgently needed. We investigated the correlation between blood-based β-actin (ACTB) methylation and the risk of stroke in a prospective nested case-control study.

Methods

The methylation level of ACTB was quantitatively determined by mass spectrometry in 139 stroke cases who developed stroke within 2 years after recruitment and 147 age- and sex-matched controls who remained stroke-free in a median follow-up of 2.71 years.

Results

We observed a highly significant correlation between hypomethylation of one CpG site of ACTB and increased risk of stroke in an onset-time-dependent manner (for onset time ≤ 1.5 years: odds ratio (OR) per + 10% methylation = 0.76, P = 0.001; for onset time ≤ 1.32 years: OR per + 10% methylation = 0.59, P = 7.82 × 10^-7; for onset time ≤ 1 year: OR per + 10% methylation = 0.43, P = 3.00 × 10^-6), and the increased cumulative incidence of stroke (log-rank P = 3.13 × 10^-7). Neighboring CpG sites showed an inverse correlation with age and drinking status in controls (P < 0.05) but not in stroke cases.

Conclusion

We firstly reported the blood-based ACTB methylation as a marker for the risk evaluation and preclinical detection of stroke, which can be further modified by age and drinking.

The association between RAPSN methylation in peripheral blood and breast cancer in the Chinese population

DNA methylation in peripheral blood is associated with breast cancer (BC) but has mainly been studied in Caucasian populations. We investigated the association between blood-based methylation of receptor-associated protein of the synapse (RAPSN) and BC in Chinese population. The methylation levels of 12 RAPSN CpG sites were quantitatively evaluated by mass spectrometry in two case-control studies with 283 sporadic BC cases and 331 controls totally. The association was analyzed by logistic regression adjusted for covariants. The RAPSN methylation levels in patients with variant clinical characteristics were investigated by non-parametric tests. We found a significant association between BC and altered RAPSN methylation in blood in women at premenopausal and perimenopausal (age < 50 years old), but not in the elder women. This was approved by two independent case-control studies as well as by combining the subjects of the two studies (taken all subjects together, age < 50 years old, per 5% of methylation, odds ratio (OR) range from 1.17 to 1.30 for two CpG sites; OR = 0.75 for one CpG site; all p values < 0.02). This age-related RAPSN methylation was further modified by human epidermal growth factor receptor 2 (HER2) status (age < 50 years old, HER2 negative, per 5% of methylation, OR range from 1.27 to 1.48 for two CpG sites; OR = 0.76 for one CpG site; all p values < 0.02). We elucidated an association between BC and blood-based RAPSN methylation influenced by age and the status of HER2 in Chinese population.

Recent Discoveries of Macromolecule- and Cell-Based Biomarkers and Therapeutic Implications in Breast Cancer

Breast cancer is the most commonly diagnosed cancer type and the leading cause of cancer-related mortality in women worldwide. Breast cancer is fairly heterogeneous and reveals six molecular subtypes: luminal A, luminal B, HER2+, basal-like subtype (ER−, PR−, and HER2−), normal breast-like, and claudin-low. Breast cancer screening and early diagnosis play critical roles in improving therapeutic outcomes and prognosis. Mammography is currently the main commercially available detection method for breast cancer; however, it has numerous limitations. Therefore, reliable noninvasive diagnostic and prognostic biomarkers are required. Biomarkers used in cancer range from macromolecules, such as DNA, RNA, and proteins, to whole cells. Biomarkers for cancer risk, diagnosis, proliferation, metastasis, drug resistance, and prognosis have been identified in breast cancer. In addition, there is currently a greater demand for personalized or precise treatments; moreover, the identification of novel biomarkers to further the development of new drugs is urgently needed. In this review, we summarize and focus on the recent discoveries of promising macromolecules and cell-based biomarkers for the diagnosis and prognosis of breast cancer and provide implications for therapeutic strategies.

Promotion of the occurrence of endometrioid carcinoma by S100 calcium binding protein P

Background

Endometrial cancer, one of the most common malignant tumors, is a serious threat to women’s health. Endometrial hyperplasia is a precursor of endometrial cancer. S100 calcium binding protein P (S100P) has been found to play important roles in many types of cancer. The present study aimed to investigate the expression of S100P in endometrial cancer and its precursor lesions, and to explore the possible mechanisms.

Methods

We collected paraffin sections of normal endometrium, simple and complex non-atypical hyperplasia, atypical hyperplasia, and endometrioid carcinoma. The expression of S100P in endometrial cancer and its precancerous lesions was observed using immunohistochemistry. We also cultured primary endometrial cells and endometrial cancer cell lines (Ishikawa and RL95–2), and observed the expression of S100P in these cells. Laser confocal microscopy was used to observe the co-localization of S100P and its interacting protein Ezrin in RL95–2 cells. We employed lentiviruses to knockdown and overexpress S100P and then detected the F-actin distribution and cell invasion using phalloidin staining and Transwell assays.

Results

There was a gradual increase in the S100P signal as the disease progressed from normal endometrium and simple non-atypical hyperplasia, to complex non-atypical hyperplasia, atypical hyperplasia, and then to endometrial cancer. S100P was mainly distributed in the cytoplasm and co-localized with Ezrin in endometrial cancer cells. After knocking down S100P, F-actin aggregated in the nucleus or to the local cell membrane. Furthermore, knockdown of S100P in Ishikawa cells decreased their cell invasion capability. Meanwhile, S100P overexpression in endometrial stromal cells increased cell invasion.

Conclusions

These data suggested that S100P might be involved in the occurrence and development of endometrial cancer via interaction with Ezrin and re-organization of F-actin to promote cell invasion.

The Association Between Breast Cancer and Blood-Based Methylation of S100P and HYAL2 in the Chinese Population

Previous work has shown that DNA methylation in peripheral blood may be associated with malignancy; however, these studies have mainly been conducted within Caucasian populations. Here, we investigated the association between blood-based methylation of S100 calcium-binding protein P gene (S100P) and hyaluronoglucosaminidase 2 gene (HYAL2) and breast cancer (BC) via mass spectrometry in two independent case-control studies of the Chinese population with a total of 351 BC cases and 427 cancer-free female controls. In Study I, in which subjects had an average of 45 years, hypomethylation of S100P showed a protective effect for women ≤45 years (six out of nine CpG sites, p < 0.05) but not for women >45 years. In contrast, hypomethylation of HAYL2 was not correlated with BC in women ≤45 years but was a risk factor for women >45 years (three out of four CpG sites, p < 0.05). We proposed an age-dependent correlation between BC and methylation of S100P and HYAL2 and performed further validation in Study II with older subjects (average age = 52.5 years), where hypomethylation of both S100P and HYAL2 was a risk factor for BC (p < 0.05 for 10 CpG sites) as reported in Caucasians who develop BC around 55 years old. Together with the observation that Chinese cancer-free females having variant basal methylation levels comparing to Caucasians, we assumed that blood-based methylation might be modified by ethnic background, hormone status, and lifestyle. Here, we highlighted that the epigenetic biomarkers warrant validations when its application in variant ethnic groups is considered.

Blood DNA Methylation and Breast Cancer: A Prospective Case-Cohort Analysis in the Sister Study

BACKGROUND

Peripheral blood DNA methylation may be associated with breast cancer, but studies of candidate genes and global and genome-wide DNA methylation have been inconsistent.

METHODS

We performed an epigenome-wide study using Infinium HumanMethylation450 BeadChips with prospectively collected blood DNA samples from the Sister Study (1552 cases, 1224 subcohort). Differentially methylated cytosine-phosphate-guanine sites (dmCpGs) were identified using case-cohort proportional hazard models and replicated using deposited data from European Prospective Investigation into Cancer and Nutrition in Italy (EPIC-Italy) (n = 329). The correlation between methylation and time to diagnosis was examined using robust linear regression. Causal or consequential relationships of methylation to breast cancer were examined by Mendelian randomization using OncoArray 500 K single-nucleotide polymorphism data. All statistical tests were two-sided.

RESULTS

We identified 9601 CpG markers associated with invasive breast cancer (false discovery rate = q < 0.01), with 510 meeting a strict Bonferroni correction threshold (10-7). A total of 2095 of these CpGs replicated in the independent EPIC-Italy dataset, including 144 meeting the Bonferroni threshold. Sister Study women who developed ductal carcinoma in situ had methylation similar to noncases. Most (1501, 71.6%) dmCpGs showed lower methylation in invasive cases. In case-only analysis, methylation was statistically significantly associated (false discovery rate = q < 0.05) with time to diagnosis for 892 (42.6%) of the dmCpGs. Analyses based on genetic association suggest that methylation differences are likely a consequence rather than a cause of breast cancer. Pathway analysis shows enrichment of breast cancer-related gene pathways, and dmCpGs are overrepresented in known breast cancer susceptibility genes.

CONCLUSIONS

Our findings suggest that the DNA methylation profile of blood starts to change in response to invasive breast cancer years before the tumor is clinically detected.

Association between the methylation of the STAT1 and SOCS3 in peripheral blood and gastric cancer

BACKGROUND AND AIM

DNA methylation is an important epigenetic modification that can promote the development of various cancers. The STAT1 and SOCS3 have been observed to be hypermethylated in tumor tissues and peripheral blood. This study aimed to explore the relationship between the methylation status of the STAT1 and SOCS3 in peripheral blood and gastric cancer (GC).

METHODS

This hospital-based case-control study involved 372 patients with GC and 379 controls. The methylation status of the STAT1 and SOCS3 was semiquantitatively determined using the methylation-sensitive high-resolution melting method. Logistic regression analysis was used to analyze the relationship between the STAT1 and SOCS3 methylation status and GC susceptibility. Moreover, propensity scores were used to control confounding factors.

RESULTS

Compared with negative methylation, the positive methylation of SOCS3 significantly increased the risk of GC (OR_a  = 1.820, 95% CI: 1.247-2.658, P = 0.002). This trend was also found via stratified analysis, and methylation positivity of the SOCS3 significantly increased the risk of GC in the < 60 years group, in the ≥ 60 years group, and in the positive Helicobacter pylori infection group (OR_a  = 1.654, 95% CI: 1.029-2.660, P = 0.038; OR_a  = 1.957, 95% CI: 1.136-3.376, P = 0.016; OR_a  = 2.084, 95% CI: 1.270-3.422, P = 0.004, respectively). Additionally, no significant association was found between STAT1 methylation and GC risk (OR_a  = 0.646, 95% CI: 0.363-1.147, P = 0.135). This study found that the interaction between the methylation status of STAT1 and SOCS3 and environmental factors did not have an impact on GC risk.

CONCLUSION

SOCS3 methylation may serve as a new potential biomarker for GC susceptibility.

Aberrantly Methylated cfDNA in Body Fluids as a Promising Diagnostic Tool for Early Detection of Breast Cancer

Breast malignancies are the leading type of cancer among women. Its prevention and early detection, particularly in young women, remains challenging. To this end, cell-free DNA (cfDNA) detected in body fluids demonstrates great potential for early detection of tissue transformation and altered molecular setup, such as epigenetic profiles. Aberrantly methylated cfDNA in body fluids could therefore serve as a potential diagnostic and prognostic tool in breast cancer management. Abnormal methylation may lead to both an activation of oncogenes via hypomethylation and an inactivation of tumor suppressor genes by hypermethylation. We update the state of the art in the area of aberrant cfDNA methylation analyses as a diagnostic and prognostic tool in breast cancer, report on the main technological challenges, and provide an outlook for advancing the overall management of breast malignancies based on cfDNA as a target for diagnosis and tailored therapies.

Integrating transcriptome-wide study and mRNA expression profiles yields novel insights into the biological mechanism of chondropathies

Background

Chondropathies are a group of cartilage diseases, which share some common pathogenetic features. The etiology of chondropathies is still largely obscure now.

Methods

A transcriptome-wide association study (TWAS) was performed using the UK Biobank genome-wide association study (GWAS) data of chondropathies (including 1314 chondropathy patients and 450,950 controls) with gene expression references of muscle skeleton (MS) and peripheral blood (YBL). The candidate genes identified by TWAS were further compared with three gene expression profiles of osteoarthritis (OA), cartilage tumor (CT), and spinal disc herniation (SDH), to confirm the functional relevance between the chondropathies and the candidate genes identified by TWAS. Functional mapping and annotation (FUMA) was used for the gene ontology enrichment analyses. Immunohistochemistry (IHC) was conducted to validate the accuracy of integrative analysis results.

Results

Integrating TWAS and mRNA expression profiles detected 84 candidate genes for knee OA, such as DDX20 (P_{TWAS YBL} = 1.79 × 10^− 3, fold change (FC) = 2.69), 10 candidate genes for CT, such as SRGN (P_{TWAS YBL} = 1.46 × 10^− 3, FC = 3.36), and 4 candidate genes for SDH, such as SUPV3L1 (P_{TWAS YBL} = 3.59 × 10^− 3, FC = 3.22). Gene set enrichment analysis detected 73 GO terms for knee OA, 3 GO terms for CT, and 1 GO term for SDH, such as mitochondrial protein complex (P = 7.31 × 10^− 5) for knee OA, cytokine for CT (P = 1.13 × 10^− 4), and ion binding for SDH (P = 3.55 × 10^− 4). IHC confirmed that the protein expression level of DDX20 was significantly different between knee OA cartilage and healthy control cartilage (P = 0.0358).

Conclusions

Multiple candidate genes and GO terms were detected for chondropathies. Our findings may provide a novel insight in the molecular mechanisms of chondropathies.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1978-8) contains supplementary material, which is available to authorized users.

Molecular changes during extended neoadjuvant letrozole treatment of breast cancer: distinguishing acquired resistance from dormant tumours

BACKGROUND

The risk of recurrence for endocrine-treated breast cancer patients persists for many years or even decades following surgery and apparently successful adjuvant therapy. This period of dormancy and acquired resistance is inherently difficult to investigate; previous efforts have been limited to in-vitro or in-vivo approaches. In this study, sequential tumour samples from patients receiving extended neoadjuvant aromatase inhibitor therapy were characterised as a novel clinical model.

METHODS

Consecutive tumour samples from 62 patients undergoing extended (4-45 months) neoadjuvant aromatase inhibitor therapy with letrozole were subjected to transcriptomic and proteomic analysis, representing before (≤ 0), early (13-120 days), and long-term (> 120 days) neoadjuvant aromatase inhibitor therapy with letrozole. Patients with at least a 40% initial reduction in tumour size by 4 months of treatment were included. Of these, 42 patients with no subsequent progression were classified as "dormant", and the remaining 20 patients as "acquired resistant".

RESULTS

Changes in gene expression in dormant tumours begin early and become more pronounced at later time points. Therapy-induced changes in resistant tumours were common features of treatment, rather than being specific to the resistant phenotype. Comparative analysis of long-term treated dormant and resistant tumours highlighted changes in epigenetics pathways including DNA methylation and histone acetylation. The DNA methylation marks 5-methylcytosine and 5-hydroxymethylcytosine were significantly reduced in resistant tumours compared with dormant tissues after extended letrozole treatment.

CONCLUSIONS

This is the first patient-matched gene expression study investigating long-term aromatase inhibitor-induced dormancy and acquired resistance in breast cancer. Dormant tumours continue to change during treatment whereas acquired resistant tumours more closely resemble their diagnostic samples. Global loss of DNA methylation was observed in resistant tumours under extended treatment. Epigenetic alterations may lead to escape from dormancy and drive acquired resistance in a subset of patients, supporting a potential role for therapy targeted at these epigenetic alterations in the management of resistance to oestrogen deprivation therapy.

Relationship Between DNA Methylation in Key Region and the Differential Expressions of Genes in Human Breast Tumor Tissue

Breast cancer has a high mortality rate for females. Aberrant DNA methylation plays a crucial role in the occurrence and progression of breast carcinoma. By comparing DNA methylation differences between tumor breast tissue and normal breast tissue, we calculate and analyze the distributions of the hyper- and hypomethylation sites in different function regions. Results indicate that enhancer regions are often hypomethylated in breast cancer. CpG islands (CGIs) are mainly hypermethylated, while the flanking CGI (shores and shelves) is more easily hypomethylated. The hypomethylation in gene body region is related to the upregulation of gene expression, and the hypomethylation of enhancer regions is closely associated with gene expression upregulation in breast cancer. Some key hypomethylation sites in enhancer regions and key hypermethylation sites in CGIs for regulating key genes are, respectively, found, such as oncogenes ESR1 and ERBB2 and tumor suppressor genes FBLN2, CEBPA, and FAT4. This suggests that the recognizing methylation status of these genes will be useful for the diagnosis of breast cancer.

Cell-type deconvolution from DNA methylation: a review of recent applications

Recent advances in cell-type deconvolution approaches are adding to our understanding of the biology underlying disease development and progression. DNA methylation (DNAm) can be used as a biomarker of cell types, and through deconvolution approaches, to infer underlying cell type proportions. Cell-type deconvolution algorithms have two main categories: reference-based and reference-free. Reference-based algorithms are supervised methods that determine the underlying composition of cell types within a sample by leveraging differentially methylated regions (DMRs) specific to cell type, identified from DNAm measures of purified cell populations. Reference-free algorithms are unsupervised methods for use when cell-type specific DMRs are not available, allowing scientists to estimate putative cellular proportions or control for potential confounding from cell type. Reference-based deconvolution is typically applied to blood samples and has potentiated our understanding of the relation between immune profiles and disease by allowing estimation of immune cell proportions from archival DNA. Bioinformatic analyses using DNAm to infer immune cell proportions, part of a new field known as Immunomethylomics, provides a new direction for consideration in epigenome wide association studies (EWAS).

Blood DNA methylation as a potential biomarker of dementia: A systematic review

Dementia is a major public health issue with rising prevalence rates, but many individuals remain undiagnosed. Accurate and timely diagnosis is key for the optimal targeting of interventions. A noninvasive, easily measurable peripheral biomarker would have greatest utility in population-wide diagnostic screening. Epigenetics, including DNA methylation, is implicated in dementia; however, it is unclear whether epigenetic changes can be detected in peripheral tissue. This study aimed to systematically review the evidence for an association between dementia and peripheral DNA methylation. Forty-eight studies that measured DNA methylation in peripheral blood were identified, and 67% reported significant associations with dementia. However, most studies were underpowered and limited by their case-control design. We emphasize the need for future longitudinal studies on large well-characterized populations, measuring epigenetic patterns in asymptomatic individuals. A biomarker detectable in the preclinical stages of the disease would have the greatest utility in future intervention and treatment trials.