Real-time analysis of the cancer genome and fragmentome from plasma and urine cell-free DNA using nanopore sequencing.

Cell-free DNA (cfDNA) can be isolated and sequenced from blood and/or urine of cancer patients. Conventional short-read sequencing lacks deployability and speed and can be biased for short cfDNA fragments. Here, we demonstrate that with Oxford Nanopore Technologies (ONT) sequencing we can achieve delivery of genomic and fragmentomic data from liquid biopsies. Copy number aberrations and cfDNA fragmentation patterns can be determined in less than 24 h from sample collection. The tumor-derived cfDNA fraction calculated from plasma of lung cancer patients and urine of bladder cancer patients was highly correlated (R = 0.98) with the tumor fraction calculated from short-read sequencing of the same samples. cfDNA size profile, fragmentation patterns, fragment-end composition, and nucleosome profiling near transcription start sites in plasma and urine exhibited the typical cfDNA features. Additionally, a high proportion of long tumor-derived cfDNA fragments (> 300 bp) are recovered in plasma and urine using ONT sequencing. ONT sequencing is a cost-effective, fast, and deployable approach for obtaining genomic and fragmentomic results from liquid biopsies, allowing the analysis of previously understudied cfDNA populations.

Evaluation of six methylation markers derived from genome-wide screens for detection of cervical precancer and cancer.

Aim: To evaluate the triage performance of six host-cell DNA methylation markers derived from two genome-wide discovery screens for detection of cervical precancer (cervical intraepithelial neoplasia 3 [CIN]) and cancer. Materials & methods: Human papillomavirus-positive cervical scrapes of controls (≤CIN1; n = 352) and women diagnosed with CIN3 (n = 175) or cervical cancer (n = 50) were analyzed for methylation of ASCL1, LHX8, ST6GALNAC5, GHSR, SST and ZIC1. Results: Methylation levels increased significantly with disease severity (all markers p < 0.001). Three markers (ASCL1, LHX8, ZIC1) showed receiver operating characteristic curves with area under the curve >0.800 after leave-one-out cross-validation. Bi-marker panel ASCL1/LHX8 had highest area under the curve (0.882), and detected 83.4% of CIN3 and all cervical cancers at specificity of 82.4%. Conclusion: All six methylation markers showed an equivalent, high performance for the triage of human papillomavirus-positive women using cervical scrapes with complementarity between markers.

DNA methylation markers for endometrial cancer detection in minimally invasive samples: a systematic review.

Aim: DNA methylation testing for endometrial cancer detection in minimally invasive specimens is a promising tool to improve screening and diagnostic procedures. Available literature was systematically reviewed to assess the potential of this approach and define methylation markers deserving further development. Methods: A systematic search up to March 31 2020 was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results: 15 methylation markers with an area under the curve value of ≥ 0.80 for endometrial cancer detection in cytological specimens were selected from nine studies. Conclusion: Detection of methylation markers in cytological samples indicate the feasibility of minimally invasive testing methods, potentially guiding diagnosis and detection of endometrial cancer in high-risk women and in cancer screening programs.

Altered microRNA processing proteins in HPV-induced cancers.

High-risk human papilloma virus (hrHPV) infections are associated with the development of anogenital cancers, in particular cervical cancer, and a subset of head and neck cancers. Previous studies have shown that microRNAs (miRNAs) contribute to the development and progression of HPV-induced malignancies. miRNAs are small non-coding RNAs that exist as multiple length and sequence variants, termed isomiRs. Efficient processing of miRNAs and generation of isomiRs is accomplished by several processing proteins. Deregulation of Drosha, AGO2, and TENT2, among others, has been observed in HPV-induced cancers and was even found at the precancerous stage. This suggests that miRNA processing proteins may be involved during early cancer development and that the generated isomiRs could provide promising biomarkers for early cancer diagnosis.

A two-gene methylation signature for the diagnosis of bladder cancer in urine.

AIM: To analyze the potential of 14 cancer-associated genes, including six miRNAs, for bladder cancer (BC) diagnosis in urine. PATIENTS & METHODS: DNA methylation levels of 14 genes were analyzed in urine of 72 BC patients and 75 healthy controls using quantitative methylation-specific PCR. Multivariate logistic regression analysis was used to determine an optimal marker panel. RESULTS: Ten genes were significantly hypermethylated in BC patients. The GHSR/MAL combination showed the best diagnostic performance, reaching a sensitivity of 92% (95% CI: 86-99) and a specificity of 85% (95% CI: 76-94). CONCLUSION: We identified a novel two-gene panel with a high diagnostic accuracy for BC that can be applied in a noninvasive, urine-based test.

Detection of hypermethylated genes as markers for cervical screening in women living with HIV.

INTRODUCTION: To evaluate the performance of hypermethylation analysis of ASCL1, LHX8 and ST6GALNAC5 in physician-taken cervical scrapes for detection of cervical cancer and cervical intraepithelial neoplasia (CIN) grade 3 in women living with HIV (WLHIV) in South Africa. METHODS: Samples from a prospective observational cohort study were used for these analyses. Two cohorts were included: a cohort of WLHIV who were invited for cervical screening (n = 321) and a gynaecologic outpatient cohort of women referred for evaluation of abnormal cytology or biopsy proven cervical cancer (n = 108, 60% HIV seropositive). Cervical scrapes collected from all subjects were analysed for hypermethylation of ASCL1, LHX8 and ST6GALNAC5 by multiplex quantitative methylation specific PCR (qMSP). Histology endpoints were available for all study subjects. RESULTS: Hypermethylation levels of ASCL1, LHX8 and ST6GALNAC5 increased with severity of cervical disease. The performance for detection of CIN3 or worse (CIN3+ ) as assessed by the area under the receiver operating characteristic (ROC) curves (AUC) was good for ASCL1 and LHX8 (AUC 0.79 and 0.81 respectively), and moderate for ST6GALNAC5 (AUC 0.71). At a threshold corresponding to 75% specificity, CIN3+ sensitivity was 72.1% for ASCL1 and 73.8% for LHX8 and all samples from women with cervical cancer scored positive for these two markers. CONCLUSIONS: Hypermethylation analysis of ASCL1 or LHX8 in cervical scrape material of WLHIV detects all cervical carcinomas with an acceptable sensitivity and good specificity for CIN3+ , warranting further exploration of these methylation markers as a stand-alone test for cervical screening in low-resource settings.

The diagnostic accuracy of methylation markers in urine for the detection of bladder cancer: a systematic review.

AIM: Several urinary hypermethylation-markers (hmDNA) have been described for bladder cancer (BC) detection, but none have been able to replace cystoscopy yet. We systematically reviewed and evaluated current literature on urinary hmDNA markers for BC diagnostics. PATIENTS & METHODS: A systematic search of PubMed, EMBASE.com and The Cochrane Library up to February 2017 using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, was conducted. RESULTS: A total of 30/42 studies included compared gene panels, with varying sensitivities (52-100%) and specificities (0-100%). Considerable heterogeneity across studies was observed and most was case-control studies. CONCLUSION: Reported diagnostic accuracy of urinary hmDNA for BC detection is highly variable and there is a lack of validation studies. Recent studies indicate that complementary markers are needed to allow for clinical implementation.

Somatic mutation in PIK3CA is a late event in cervical carcinogenesis.

Somatic mutations in cervical intraepithelial neoplasia (CIN) are largely unknown. Here, we profiled 35 cervical carcinomas and 23 CIN grade 2/3 (CIN2/3) for mutations in 48 cancer-related genes using a Next Generation Sequencing-based cancer panel. PIK3CA exon 9 was the most frequently mutated locus in cervical carcinoma and the only mutated locus detected in CIN2/3. These PIK3CA exon 9 mutation findings were verified in a large, independent series (n = 647) covering all stages of cervical carcinogenesis using high resolution melting-guided Sanger sequencing. PIK3CA exon 9 mutation frequency was 37.1% (13/35; 95%CI 21.2-54.0%) in cervical carcinoma, and 2.4% (5/209; 95%CI 0.5-4.7%) in CIN3. No PIK3CA exon 9 mutations were detected in CIN2 (0/144), CIN1 (0/154) and normal cervix (0/105). In a third series of 46 CIN2/3 lesions from women with a known 5-year history of preceding high-risk human papillomavirus (hrHPV) infection, detection of PIK3CA exon 9 mutation was confined to 2 (5.4%; 95%CI 0.0-13.2%) CIN3 lesions with preceding hrHPV infection ≥5 years, and was absent in those with a short duration (<5 years) of preceding hrHPV infection. In conclusion, somatic mutation in PIK3CA represents a late event during cervical carcinogenesis, detected in a substantial subset of cervical carcinoma, but only in a minority of CIN3.

Interplay between promoter methylation and chromosomal loss in gene silencing at 3p11-p14 in cervical cancer.

Loss of 3p11-p14 is a frequent event in epithelial cancer and a candidate prognostic biomarker in cervical cancer. In addition to loss, promoter methylation can participate in gene silencing and promote tumor aggressiveness. We have performed a complete mapping of promoter methylation at 3p11-p14 in two independent cohorts of cervical cancer patients (n = 149, n = 121), using Illumina 450K methylation arrays. The aim was to investigate whether hyperm-ethylation was frequent and could contribute to gene silencing and disease aggressiveness either alone or combined with loss. By comparing the methylation level of individual CpG sites with corresponding data of normal cervical tissue, 26 out of 41 genes were found to be hypermethylated in both cohorts. The frequency of patients with hypermethylation of these genes was found to be higher at tumor stages of 3 and 4 than in stage 1 tumors. Seventeen of the 26 genes were transcriptionally downregulated in cancer compared to normal tissue, whereof 6 genes showed a significant correlation between methylation and expression. Integrated analysis of methylation, gene dosage, and expression of the 26 hypermethylated genes identified 3 regulation patterns encompassing 8 hypermethylated genes; a methylation driven pattern (C3orf14, GPR27, ZNF717), a gene dosage driven pattern (THOC7, PSMD6), and a combined methylation and gene dosage driven pattern (FHIT, ADAMTS9, LRIG1). In survival analysis, patients with both hypermethylation and loss of LRIG1 had a worse outcome compared to those harboring only hypermethylation or none of the events. C3orf14 emerged as a novel methylation regulated suppressor gene, for which knockdown was found to promote invasive growth in human papilloma virus (HPV)-transformed keratinocytes. In conclusion, hypermethylation at 3p11-p14 is common in cervical cancer and may exert a selection pressure during carcinogenesis alone or combined with loss. Information on both events could lead to improved prognostic markers.