Genome-wide methylome analysis using MethylCap-seq uncovers 4 hypermethylated markers with high sensitivity for both adeno- and squamous-cell cervical carcinoma

The identification and validation of EphA7 hypermethylation, a novel biomarker, in cervical cancer

BACKGROUND

Aberrant methylation of EphA7 has been reported in the process of carcinogenesis but not in cervical cancer. Therefore, an integration study was performed to explore the association between EphA7 hypermethylation and cervical cancer and validate the potential value of EphA7 hypermethylation in the diagnosis of cervical cancer.

METHODS

We performed an integration study to identify and validate the association between EphA7 methylation and cervical cancer. First, data on EphA7 methylation and expression in cervical cancer were extracted and analyzed via bioinformatics tools. Subsequently, CRISPR-based methylation perturbation tools (dCas9-Tet1/DNMT3a) were constructed to further demonstrate the association between DNA methylation and EphA7 expression. Ultimately, the clinical value of EphA7 methylation in cervical cancer was validated in cervical tissues and Thinprep cytologic test (TCT) samples by methylation-specific PCR (MSP) and quantitative methylation-specific PCR (QMSP), respectively.

RESULTS

Pooled analysis showed that EphA7 promoter methylation levels were significantly increased in cervical cancer compared to normal tissues (P < 0.001) and negatively correlated with EphA7 expression. These prediction results were subsequently confirmed in cell lines; moreover, CRISPR-based methylation perturbation tools (dCas9-Tet1/DNMT3a) demonstrated that DNA methylation participates in the regulation of EphA7 expression directly. Consistent with these findings, the methylation level and the positive rate of EphA7 gradually increased with severity from normal to cancer stages in TCT samples (P < 0.01).

CONCLUSIONS

EphA7 hypermethylation is present in cervical cancer and is a potential biomarker for the diagnosis of cervical cancer.

Tumor DNA Methylation Profiles Enable Diagnosis, Prognosis Prediction, and Screening for Cervical Cancer

Background

DNA-methylation-based machine learning algorithms have demonstrated powerful diagnostic capabilities, and these tools are currently emerging in many fields of tumor diagnosis and patient prognosis prediction. This work aimed to identify novel DNA methylation diagnostic biomarkers for differentiating cervical cancer (CC) from normal tissues, as well as a prognostic prediction model to predict survival of CC patients.

Methods

The methylation profiles with the available clinical characteristics were downloaded from the Gene Expression Omnibus (GEO) database and The Cancer Genome Atlas (TCGA) program. We first screened out the differential methylation sites in CC and normal tissues and performed multiple statistical analyses to discover DNA methylation diagnostic markers that are used to distinguish CC and normal control. Then, we developed a methylation-based survival model to improve risk stratification.

Results

A diagnostic prediction panel consists of five CpG markers that could predict cervical cancer versus normal tissue with highly correct rate of 100%, and cg16428251, cg22341310, and cg23316360 which in diagnostic prediction panel all could yield high sensitivity and specificity for detection of CC and normal in six cohorts (area under curve [AUC] > 0.8), in addition to excellent performance in discriminating between CC and normal sample. The diagnostic marker panel also effectively predicted the CIN3 versus normal tissue with high accuracy in two datasets (AUC = 0.80, 0.789, respectively). Furthermore, a prognostic prediction model aggregated two CpG markers that effectively stratified the prognosis of high-risk and low-risk groups (training cohort: hazard ratio [HR] 4, 95% CI: 1.7–9.6, P = 0.0021; testing cohort: hazard ratio [HR] 1.9, 95% CI: 1.2–3.1, P = 0.0072).

Conclusion

The findings of our study showed that DNA methylation markers are of great value in the diagnosis and prognosis of CC.

DNA methylation markers as triage test for the early identification of cervical lesions in a Chinese population

Objective strategies are required in cervical cancer screening. We have identified several DNA methylation markers with high sensitivity and specificity to detect cervical intraepithelial neoplasia 2 or worse (CIN2+) in Dutch women. Our study aims to analyze the diagnostic characteristics of these markers in a Chinese cohort. A total of 246 liquid-based cytology samples were included, of which 205 women underwent colposcopy due to an abnormal cytology result (atypical squamous cells of undetermined significance [ASCUS] or worse), while 227 were tested high-risk human papillomavirus (hrHPV) positive. All six individual markers (ANKRD18CP, C13ORF18, EPB41L3, JAM3, SOX1 and ZSCAN1) showed enhanced methylation levels and frequency with increasing severity of the underlying lesion (P ≤ .001). In cytological abnormal women, sensitivity to detect CIN2+ was 79%, 76% and 72% for the three panels (C13ORF18/EBP41L3/JAM3, C13ORF18/ANKRD18CP/JAM3 and ZSCAN1/SOX1, respectively), with a specificity of 57%, 65% and 68%. For the first two panels, these diagnostic characteristics were similar to the Dutch cohort, while for ZSCAN1/SOX1 the sensitivity was higher in the Chinese cohort, but with a lower specificity (both P < .05). In hrHPV-positive samples, similar sensitivity and specificity for the detection of CIN2+ were found as for the abnormal cytology cohort, which were now all similar between both cohorts and non-inferior to HPV16/18 genotyping. Our analysis reveals that the diagnostic performances are highly comparable for C13ORF18/EBP41L3/JAM3 and C13ORF18/ANKRD18CP/JAM3 methylation marker panels in both Chinese and Dutch cohorts. In conclusion, methylation panels identified in a Dutch population are also applicable for triage testing in cervical cancer screening in China.

SOX1 Promoter Hypermethylation as a Potential Biomarker for High-Grade Squamous Intraepithelial Neoplasia Lesion and Cervical Carcinoma: A Meta-Analysis With Trial Sequential Analysis

Background: DNA methylation has been widely assessed as a potential biomarker for the early detection of cervical cancer (CC). Herein, we assessed the associations of SOX1 promoter hypermethylation with squamous intraepithelial lesion and CC.

Methods: Published studies and genome-wide methylation datasets were searched from electronic databases (up to April 2019). The associations of SOX1 hypermethylation with high-grade squamous intraepithelial lesion (HSIL) and CC risks were evaluated by odds ratios (ORs) and 95% confidence intervals (CIs). The summary receiver operator characteristic test was used to assess the diagnostic value of the SOX1 promoter hypermethylation of CC and intraepithelial neoplasia type III or worse (CIN3+). Trial sequential analysis (TSA) was performed to evaluate the stability of results and estimate the required information size (RIS).

Results: In this meta-analysis of 17 published studies, the SOX1 methylation rates increased among low-grade SIL (LSIL, 27.27%), HSIL (40.75%), and CC (84.56%) specimens. Compared with control specimens, SOX1 promoter hypermethylation progressively increased the risk of HSIL by 4.20-fold (p < 0.001) and CC by 41.26-fold (p < 0.001). The pooled sensitivity of SOX1 methylation was estimated to be 0.85 (95% CI: 0.81–0.88) in differentiating patients with CC, corresponding to a specificity of 0.72 (95% CI: 0.69–0.75) and an area under the curve (AUC) of 0.93. Furthermore, the pooled sensitivity of SOX1 methylation was estimated to be 0.75 (95% CI: 0.72–0.78) in differentiating patients with CIN3+, corresponding to a specificity of 0.71 (95% CI: 0.69–0.73) and an AUC of 0.84. The pooled results of TCGA and GEO datasets showed that all CpG sites in SOX1 were associated with CC and 16 of 19 CpG sites were associated with HSIL. The results of TSA illustrated that the size was sufficient and significant associations were observed.

Conclusion: This meta-analysis indicated that SOX1 promoter hypermethylation might have a potential value in the clinical diagnosis of CC and CIN3+.

Impact of AAV2 and Hepatitis B Virus Integration Into Genome on Development of Hepatocellular Carcinoma in Patients with Prior Hepatitis B Virus Infection

PURPOSE

Hepatitis B viral (HBV) DNA is frequently integrated into the genomes of hepatocellular carcinoma (HCC) in patients with chronic HBV infection (chronic HBV, hereafter), whereas the frequency of HBV integration in patients after the disappearance of HBV (prior HBV, hereafter) has yet to be determined. This study aimed to detect integration of HBV and adeno-associated virus type 2 (AAV2) into the human genome as a possible oncogenic event.

EXPERIMENTAL DESIGN

Virome capture sequencing was performed, using HCC and liver samples obtained from 243 patients, including 73 with prior HBV without hepatitis C viral (HCV) infection and 81 with chronic HBV.

RESULTS

Clonal HBV integration events were identified in 11 (15.0%) cases of prior HBV without HCV and 61 (75.3%) cases of chronic HBV (P < 0.001). Several driver genes were commonly targeted by HBV, leading to transcriptional activation of these genes; TERT [four (5.4%) vs. 15 (18.5%)], KMT2B [two (2.7%) vs. five (6.1%)], CCNE1 [zero vs. one (1.2%)], CCNA2 [zero vs. one (1.2%)]. Conversely, CCNE1 and CCNA2 were, respectively, targeted by AAV2 only in prior HBV. In liver samples, HBV genome recurrently integrated into fibrosis-related genes FN1, HS6ST3, KNG1, and ROCK1 in chronic HBV. There was not history of alcohol abuse and 3 patients with a history of nucleoside analogue treatment for HBV in 8 prior HBV with driver gene integration.

CONCLUSIONS

Despite the seroclearance of hepatitis B surface antigen, HBV or AAV2 integration in prior HBV was not rare; therefore, such patients are at risk of developing HCC.

DNA methylation markers as a triage test for identification of cervical lesions in a high risk human papillomavirus positive screening cohort

Objective triage strategies are required to prevent unnecessary referrals for colposcopy in population‐based screening programs using primary high‐risk human papillomavirus (hrHPV) testing. We have identified several DNA methylation markers with high sensitivity and specificity for detection of high‐grade cervical intraepithelial neoplasia or worse (CIN2+) in women referred for colposcopy. Our study assessed diagnostic potential of these methylation markers in a hrHPV‐positive screening cohort. All six markers (JAM3, EPB41L3, C13orf18, ANKRD18CP, ZSCAN1 and SOX1) showed similar association across histology in the hrHPV‐positive cohort when compared to the Dutch cohort (each p > 0.15). Sensitivity for CIN2+ was higher using methylation panel C13orf18/EPB41L3/JAM3 compared to the other 2 panels (80% vs. 60% (ANKRD18CP/C13orf18/JAM3) and 63% (SOX1/ZSCAN1), p = 0.01). For CIN3+ all three methylation panels showed comparable sensitivity ranging from 68% (13/19) to 95% (18/19). Specificity of SOX1/ZSCAN1 panel (84%, 167/200) was considerably higher compared to ANKRD18CP/C13orf18/JAM3 (68%, 136/200, p = 2 × 10⁻⁵) and C13orf18/EPB41L3/JAM3 (66%, 132/200, p = 2 × 10⁻⁷). High negative predictive value (NPV) (91–95% and 96–99%) was observed for CIN2+ and CIN3+, for all three methylation panels, while positive predictive value (PPV) varied from 25 to 40% for CIN2+ and 15–27% for CIN3+. Interestingly, 118/235 samples were negative for all six markers (including 106 controls (89.8%), 6 CIN1 (5.1%), 5 CIN2 (4.2%) and 1 CIN3 (0.8%)). Methylation results from both independent cohorts were comparable as well as high sensitivity for detection of cervical cancer and its high‐grade precursors in hrHPV‐positive population. Our study therefore validates these methylation marker panels as triage test either in hrHPV‐based or abnormal cytology‐based screening programs.

What's new?

In cervical cancer screening, HPV testing provides greater sensitivity than cytology, but its lower specificity leads to some unnecessary treatment referrals. DNA methylation assays could potentially provide better specificity for identifying CIN2+ in women carrying high risk HPV. These authors investigated six previously identified CIN2+ methylation markers. They tested three different combinations of markers, and found high levels of sensitivity and specificity, making these markers potentially useful as part of a population‐based screening program.

Host-cell DNA methylation patterns during high-risk HPV-induced carcinogenesis reveal a heterogeneous nature of cervical pre-cancer

Cervical cancer development following a persistent infection with high-risk human papillomavirus (hrHPV) is driven by additional host-cell changes, such as altered DNA methylation. In previous studies, we have identified 12 methylated host genes associated with cervical cancer and pre-cancer (CIN2/3). This study systematically analyzed the onset and DNA methylation pattern of these genes during hrHPV-induced carcinogenesis using a longitudinal in vitro model of hrHPV-transformed cell lines (n = 14) and hrHPV-positive cervical scrapings (n = 113) covering various stages of cervical carcinogenesis. DNA methylation analysis was performed by quantitative methylation-specific PCR (qMSP) and relative qMSP values were used to analyze the data. The majority of genes displayed a comparable DNA methylation pattern in both cell lines and clinical specimens. DNA methylation onset occurred at early or late immortal passage, and DNA methylation levels gradually increased towards tumorigenic cells. Subsequently, we defined a so-called cancer-like methylation-high pattern based on the DNA methylation levels observed in cervical scrapings from women with cervical cancer. This cancer-like methylation-high pattern was observed in 72% (38/53) of CIN3 and 55% (11/20) of CIN2, whereas it was virtually absent in hrHPV-positive controls (1/26). In conclusion, hrHPV-induced carcinogenesis is characterized by early onset of DNA methylation, typically occurring at the pre-tumorigenic stage and with highest DNA methylation levels at the cancer stage. Host-cell DNA methylation patterns in cervical scrapings from women with CIN2 and CIN3 are heterogeneous, with a subset displaying a cancer-like methylation-high pattern, suggestive for a higher cancer risk.

SOX14 activates the p53 signaling pathway and induces apoptosis in a cervical carcinoma cell line

SOX14 is a member of the SOX family of transcription factors mainly involved in the regulation of neural development. Recently, it became evident that SOX14 is one of four hypermethylated genes in cervical carcinoma, considered as a tumor suppressor candidate in this type of malignancy. In this paper we elucidated the role of SOX14 in the regulation of malignant properties of cervical carcinoma cells in vitro. Functional analysis performed in HeLa cells revealed that SOX14 overexpression decreased viability and promoted apoptosis through altering the expression of apoptosis related genes. Our results demonstrated that overexpression of SOX14 initiated accumulation of p53, demonstrating potential cross-talk between SOX14 and the p53 signaling pathway. Further analysis unambiguously showed that SOX14 triggered posttranslational modification of p53 protein, as detected by the significantly increased level of phospho-p53 (Ser-15) in SOX14-overexpressing HeLa cells. Moreover, the obtained results revealed that SOX14 activated p53 protein, which was confirmed by elevated p21^Waf1/Cip1, a well known target gene of p53. This study advances our understanding about the role of SOX14 and might explain the molecular mechanism by which this transcription factor could exert tumor suppressor properties in cervical carcinoma.