The significant diagnostic value of human telomerase RNA component (hTERC) gene detection in high-grade cervical lesions and invasive cancer

Copy number profiling implicates thin high-grade squamous intraepithelial lesions as a true precursor of cervical human papillomavirus-induced squamous cell cancer

Full-thickness high-grade squamous intraepithelial lesions (HSIL) are precursors of invasive cervical squamous cell carcinoma (SCC). The World Health Organization (WHO) and Lower Anogenital Squamous Terminology (LAST) Standardization Project for human papilloma virus (HPV)-associated lesions divide full-thickness HSIL of the cervix into thin HSIL with one to nine cell layers thickness and the typical full-thickness HSIL of more than ten cell layers. Although HPV oncogene transcripts and p16ink4a overexpression, as markers of transforming HPV infection, are detectable in thin HSIL, the biological significance of thin HSIL in cervical carcinogenesis remains poorly understood. To further characterize thin HSIL, we performed a comparative study of chromosomal copy number variations (CNV), analysis of dysregulated genes present in the segments with CNV, and a generalized genetic complexity calculation for 31 thin HSIL, 31 thick HSIL, 24 microinvasive SCC (pT1a SCC), and 22 highly invasive SCC samples. Thin HSIL share various CNV and specific dysregulated gene pathways with thick HSIL and invasive SCC. Thin HSIL exhibited an average CNV of 11.6%, compared with 14.1% for thick HSIL, 15.5% for pT1a SCC, and 26.6% for highly invasive SCC. The CNV included gains at 1q and 3q (40 and 43%, respectively), partial loss of 3p, and loss of chromosomes 11 (18%), 16 (50%), 20 (35%), and 22 (40%). Pathways affected solely in thin HSIL were those enhancing immune evasion and primarily involved the interleukin (IL)6, IL21, and IL23 genes. ILs are transiently upregulated in response to infection and play a crucial role in mounting antitumor T-cell activity. Deregulation reflects an attempt by the HPV to evade the initial immune response of the host. The primary pathways shared by thick HSIL and invasive SCC were interactions between lymphoid and non-lymphoid cells, Notch2 signaling, tight junction (TJ) interactions (primarily of the claudin family), and FGR2 alternative splicing. Our results show that thin HSIL carry similar genetic changes as thick HSIL and SCC, indicating that thin HSIL are true precursor lesions that can progress to thick HSIL and SCC.

Evaluation of hTERT gene expression and chromosome 7 copy number variation in anal squamous intra-epithelial lesions: A pilot study

Background:

Akin to cervical squamous intra-epithelial neoplasia (CIN), anal squamous intra-epithelial lesion (a-SIL) is attributed to persistent infection with high-risk human papilloma virus infection. Amplification of human telomerase reverse transcriptase (hTERT) gene and aneuploidy are known to correlate with CIN evolution. It is plausible that the underlying genetic events in a-SIL are similar. We conducted this cross-sectional analytical study with the objective of determining expression of hTERT gene expression and chromosome 7, as marker of cell ploidy in a-SIL.

Methods:

Conventional anal cytology was performed in 86 adult consenting subjects with history of receptive anal intercourse (RAI) and 4 controls without history of RAI. Cases with a-SIL and controls were subjected to fluorescent in-situ hybridization (FISH) to evaluate hTERT gene and chromosome 7 expression, as marker of cell ploidy. Results were expressed as number of abnormal nuclei (≥3 respective signals), maximum degree of amplification, mean signals/nucleus and proportion of cases showing abnormal nuclei.

Results:

Twenty cases showed a-SIL; with 15 atypical squamous cells of undetermined significance (ASCUS), 3 low grade squamous intra-epithelial lesion (LSIL) and 2 cases of high-risk cytology. Expression of both hTERT gene and chromosome 7 increased from controls to ASCUS to LSIL with concomitant increase in proportion of cases having abnormal hTERT gene and chromosome 7 expression.

Conclusions:

Positive association of hTERT gene with a-SIL suggests its possible role in evolution of anal squamous abnormalities. Increase in chromosome 7 also correlated positively with a-SIL. These findings corroborate the similarities between squamous carcinogenesis in CIN and a-SIL.

Loop-Mediated Isothermal Amplification Assay for Detecting Tumor Markers and Human Papillomavirus: Accuracy and Supplemental Diagnostic Value to Endovaginal MRI in Cervical Cancer

OBJECTIVE

To establish the sensitivity and specificity of a human papillomavirus (HPV) and tumor marker DNA/mRNA assay for detecting cervical cancer that is transferrable to a Lab-on-a-chip platform and determine its diagnostic benefit in early stage disease when used in conjunction with high-resolution endovaginal magnetic resonance imaging (MRI).

METHODS

Forty-one patients (27 with Stage1 cervical cancer [Group1] and 14 non-cancer HPV negative controls [Group2]) had DNA and RNA extracted from cervical cytology swab samples. HPV16, HPV18, hTERT, TERC/GAPDH and MYC/GAPDH concentration was established using a loop mediated isothermal amplification (LAMP) assay. Thresholds for tumor marker detection for Group1 were set from Group2 analysis (any hTERT, TERC/GAPDH 3.12, MYC/GAPDH 0.155). Group 1 participants underwent endovaginal MRI. Sensitivity and specificity for cancer detection by LAMP and MRI individually and combined was documented by comparison to pathology.

RESULTS

Sensitivity and specificity for cancer detection was 68.8% and 77.8% if any tumor marker was positive regardless of HPV status (scenario1), and 93.8% and 55.8% if tumor marker or HPV were positive (scenario 2). Adding endovaginal MRI improved specificity to 88.9% in scenario 1 (sensitivity 68.8%) and to 77.8%% in scenario2 (sensitivity 93.8%).

CONCLUSION

Specificity for cervical cancer detection using a LAMP assay is superior with tumor markers; low sensitivity is improved by HPV detection. Accuracy for early stage cervical cancer detection is optimal using a spatially multiplexed tumor marker/HPV LAMP assay together with endovaginal MRI.

Emerging technologies for cervical cancer screening

Cervical cancer remains a concern worldwide, and cervical cancer screening plays an important role in reducing the burden of this disease. Although cytology is still the main strategy for cervical cancer screening, it has gradually changed to human papillomavirus testing. The specificity of human papillomavirus testing is lower than that of cytology, which leads to an increased rate of colposcopy after positive results. To decrease colposcopic examinations, an efficient triage method is needed for human papillomavirus screening. New biomarkers have been developed and evaluated for primary screening and triage of abnormal cytology or human papillomavirus-positive results. Their sensitivity and specificity were estimated and compared with those of cytology. In the present study, the following new techniques were examined: p16/Ki67 dual staining, DNA methylation, micro-ribonucleic acid, chromosomal abnormalities, Claudins and DNA ploidy. Evaluation studies of p16/Ki67 dual staining and DNA methylation were more advanced than those of other options. When p16/Ki67 dual staining was used for triage for human papillomavirus testing, the sensitivity of 2 or greater cervical intraepithelial neoplasia (CIN2+) detection was higher than that of cytology without decreased specificity. Although there are several types of DNA methylation, sensitivity and specificity were moderate for detecting CIN2+. S5 classifier is a commercialized product that consists of viral methylation, and high sensitivity with decreased specificity has been reported. Considering its combination with self-sampling, DNA methylation is a highly anticipated technique along with human papillomavirus testing for the next generation of cervical cancer screening. However, the backgrounds for cervical cancer screening differ among countries and further study is needed to identify the best available method.

Human telomerase RNA component (hTERC) gene expression and chromosome 7 ploidy correlate positively with histological grade of cervical intraepithelial neoplasia

OBJECTIVE

Cervical cancer screening by primary human papilloma virus detection and cytology is fraught with low specificity and variable sensitivity, respectively. Cytology-histology correlation remains modest. Biomarkers associated with early genetic events in cervical squamous carcinogenesis and detectable in cytology material are likely to be relevant. Human telomerase RNA component (hTERC) gene overexpression and aneuploidy are promising candidates in view of their reported early and consistent association with cervical squamous oncogenesis.

METHODS

We analysed hTERC gene expression and chromosome 7 ploidy by fluorescent in-situ hybridisation (FISH) in 50 women with cytological precursor squamous intraepithelial lesions and available histology outcomes. Results were expressed as percentages of cells showing ≥3 signals, mean signals/nucleus, and maximum amplitude across various cytology and histology categories. Proportions of positive cases were calculated from threshold values derived from 6 controls. Distribution of above indices with respect to ≥cervical intraepithelial neoplasia 2 (CIN2) was explored.

RESULTS

For both genetic aberrations, there was significant positive correlation (for all indices) between the proportion of positive cases and worsening cytological and histological outcomes (P < .05), with significant intergroup differences (P < .05). High-grade lesions (≥CIN2) had significantly higher results compared to <CIN2 lesions (P ≤ .001). In five discordant cases with ≥CIN2 under- or overdiagnosed on cytology, FISH supported the histological diagnosis.

CONCLUSIONS

HTERC gene amplification and chromosome 7 ploidy showed positive association with cervical squamous carcinogenesis and could be relevant in settings of discrepant cytology-histology correlation.

Identification of SEC62 as a potential marker for 3q amplification and cellular migration in dysplastic cervical lesions

Background

Chromosome 3 amplification affecting the 3q26 region is a common genomic alteration in cervical cancer, typically marking the transition of precancerous intraepithelial lesions to an invasive phenotype. Though potential 3q encoded target genes of this amplification have been identified, a functional correlation of potential oncogenic function is still missing. In this study, we investigated copy number changes and the expression level of SEC62 encoded at 3q26.2 as a new potential 3q oncogene in dysplastic cervical lesions and analyzed its role in cervical cancer cell biology.

Methods

Expression levels of Sec62 and vimentin were analyzed in liquid based cytology specimens from 107 women with varying grades of cervical dysplasia ranging from normal cases to cancer by immunofluorescence cytology. Additionally, a subset of 20 representative cases was used for FISH analyses targeting SEC62. To further explore the functional role of Sec62 in cervical cancer, HeLa cells were transfected with a SEC62 plasmid or SEC62 siRNA and analyzed for their proliferation and migration potential using real-time monitoring and trans-well systems as well as changes in the expression of EMT markers.

Results

FISH analyses of the swabbed cells showed a rising number of SEC62 gains and amplifications correlating to the grade of dysplasia with the highest incidence in high grade squamous intraepithelial lesions and squamous cell carcinomas. When analyzing the expression level of Sec62 and vimentin, we found a gradually increasing expression level of both proteins according to the severity of the dysplasia. In functional analyses, SEC62 silencing inhibited and SEC62 overexpression stimulated the migration of HeLa cells with only marginal effects on cell proliferation, the expression level of EMT markers and the cytoskeleton structure.

Conclusions

Our study suggests SEC62 as a target gene of 3q26 amplification and a stimulator of cellular migration in dysplastic cervical lesions. Hence, SEC62 could serve as a potential marker for 3q amplification, providing useful information about the dignity and biology of dysplastic cervical lesions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2739-6) contains supplementary material, which is available to authorized users.