ATL

The Role of p16/Ki-67 Immunostaining, hTERC Amplification and Fibronectin in Predicting Cervical Cancer Progression: A Systematic Review

Human papillomaviruses (HPVs) are common sexually transmitted infectious agents responsible for several anogenital and head and neck cancers. Cervical cancer (CC) is the fourth leading cause of death in women with cancer. The progression of a persistent HPV infection to cancer takes 15–20 years and can be preventable through screening. Cervical cytology (Pap smear) is the standard screening test for CC and precancerous lesions. For ASC-US and ASC-H lesions, a combination of Pap smear and HR-HPV analysis is recommended as a triage step before colposcopy. However, these tests cannot predict progression to CC. For this purpose, we summarized current scientific data on the role of p16/Ki-67 immunohistostaining, telomerase and fibronectin in predicting progression to CC. p16 and p16/Ki-67 dual staining (DS) were more specific than HR-HPV DNA testing for the detection of CIN2+/CIN3+ in women with ASC-US and LSIL. Similarly, hTERC FISH analysis significantly improved the specificity and positive predictive value of HPV DNA testing in differentiating CIN2+ from CIN2 cytological samples. In conclusion, p16 IHC, p16/Ki-67 DS and hTERC FISH amplification are all valid adjunctive biomarkers which significantly increase the sensitivity and specificity of cervical dysplasia diagnosis, especially when combined with HPV DNA testing. However, considering the global socioeconomic background, we can postulate that p16 and p16/ Ki-67 IHC can be used as a next step after positive cytology for ASC-US or LSIL specimens in low-income countries, instead of HPV DNA testing. Alternatively, if HPV DNA testing is covered by insurance, p16 or p16/Ki-67 DS and HPV DNA co-testing can be performed. In middle- and high-income countries, hTERC amplification can be performed as an adjunctive test to HPV DNA testing in women with ASC-US and LSIL.

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.

Human papillomavirus and human telomerase RNA component gene in cervical cancer progression

This study aimed to examine hTERC gene in different grades of cervical intraepithelial neoplasia (CIN) and cervical cancer, and the association between hTERC and high risk-human papillomavirus (HR-HPV) infection. Patients who underwent cervical cancer screening at the Second Affiliated Hospital of Kunming Medical University between October 2010 and December 2011 were enrolled. All patients underwent liquid-based cytology test and hybrid capture 2 (HC2) for HPV detection. hTERC was examined using fluorescence in situ hybridization (FISH). Cervical colposcopy biopsy was performed if any of the three results was positive. HC2, FISH, and pathology were compared. A total of 1200 women underwent screening, 150 patients underwent cervical biopsy: 32 in the normal group, 38 in the CIN1 group, 66 in the CIN2/3 group, and 14 in the invasive cervical cancer group. More patients had HR-HPV infection in the CIN2/3 group and ICC group compared with the CIN1 group. hTERC increased with increasing histological dysplasia. There was significant difference in hTERC positive rate between each of the three groups. More patients with hTERC gene amplification were observed in the positive HR-HPV group than in the HR-HPV negative group. In conclusion, hTERC is a potential marker for precancerous cervical cancer lesions. hTERC might be correlated with HR-HPV infection in cervical diseases.

Genomic amplification of HPV, h-TERC and c-MYC in liquid-based cytological specimens for screening of cervical intraepithelial neoplasia and cancer

Cervical cancer is one of the most prevalent female cancer types in developing countries. ThinPrep cytological test (TCT) and human papillomavirus (HPV) detection are canonical screening methods for cervical cancer currently. However, there are limitations to these techniques. The aim of the present study was to identify efficient and practical methods for the screening of cervical intraepithelial neoplasia (CIN) and carcinoma. Residual PreservCyt specimens were obtained from 1,000 women who were admitted between August 2013 and December 2015. TCT, human telomerase RNA component (h-TERC) fluorescent in situ hybridization (FISH), MYC-specific FISH and surface plasmon resonance (SPR)-HPV genotyping were performed, followed by histopathology for those patients with positive results in any of the four tests. As a result, 106, 64, 56 and 112 patients were positive in the TCT, h-TERC, c-MYC and SPR-HPV tests, respectively, resulting in 213 being scheduled for histopathology; inflammation was identified in 159 patients, CIN I in 31, CIN II in 14, CIN III in seven and invasive cervical cancer in two patients. Using histopathology as the gold standard, TCT exhibited the highest sensitivity (87.04%), while h-TERC analysis had the highest specificity (81.76%). Parallel tests demonstrated that the Youden's index of TCT + h-TERC was the highest (0.49), while the serial analysis reported that TCT + HPV had the highest Youden's index (0.53) compared with any of the biomarkers alone (TCT, 0.50; HPV, 0.29; h-TERC, 0.47). In conclusion, dual positive TCT and HPV may be an efficient approach for basic screening of cervical lesions. h-TERC amplification may serve as an auxiliary test to improve the specificity.

Telomeres and Telomerase During Human Papillomavirus-Induced Carcinogenesis

Human papillomaviruses (HPVs) belong to a small spherical virus family and are transmitted through direct contact, most often through sexual behavior. More than 200 types of HPV are known, a dozen or so of which are classified as high-risk viruses (HR HPV) and may contribute to the development of cervical cancer. HPV is a small virus with a capsid composed of L1 and L2 proteins, which are crucial for entry to the cell. The infection begins at the basal cell layer and progresses to involve cells from higher layers of the cervical epithelium. E6 and E7 viral proteins are involved in the process of carcinogenesis. They interact with suppressors of oncogenesis, including p53 and Rb proteins. This leads to DNA replication and intensive cell divisions. The persistent HR HPV infection leads to the development of dysplasia and these changes may progress to invasive cancer. During the initial stage of carcinogenesis, telomeres shorten until telomerase activates. The activation of telomerase, the enzyme necessary to extend chromosome ends (telomeres) is the key step in cell immortalization. Analyzing the expression level of hTERT and hTERC genes encoding telomerase and telomere length measurement may constitute new markers of the early carcinogenesis.

Epidemiological study of high-risk human papillomavirus infection in subjects with abnormal cytological findings in cervical cancer screening

The present study aimed to determine the genotype and age distribution of high-risk human papillomavirus (HR-HPV) and evaluate HPV-DNA in subjects with abnormal cervical cytology results by using crowd-based cervical cancer screening cytology data. The Thinprep liquid-based cytologic test (TCT) was performed from January 2013 to January 2014 in the permanent residents of Liaocheng (China) aged 21-65 years who were married or had sexual intercourse. The number of screened women totaled 20,017, among whom 937 had abnormal results, 785 of which were recalled. For subjects in the age range of 21-65 years, an HR-HPV typing test using the fluorescence hybridization method. Among the 785 cases with abnormal TCT findings, repeated testing identified atypical squamous cells of unknown significance/atypical glandular cells in 478, low-grade squamous intraepithelial lesions in 175, high squamous intraepithelial lesions in 127 and squamous cell carcinoma/adenocarcinoma in 5 cases. Among these types, infection rates of HR-HPV were 50.2, 77.1, 89.0 and 100%, respectively. Of the 785 cases with abnormal TCT results, 493 (62.8%) were HR-HPV-positive. A total of 16 types of HR-HPV were detected: HPV-16, -18, -31, -33, -35, -39, -45, -51-53, -56, -58, -59, -66, 68 and 73. Subjects infected with ≥2 types were defined as having a multi-type infection. The infection rate was high in the age groups of 26-30 and 51-55 years, accounting for 87.7% (71/81) and 79.7% (51/64), respectively, while it was lower in the >55 years group at 28.6% (14/54). The top five types of HR-HPV (stated in a decreasing order regarding positivity rate) were HPV16 (21.5%, 169/785), HPV52 (12.2%, 96/785), HPV58 (9.8%, 77/785), HPV33 (9.7%, 76/785) and HPV18 (7.5%, 59/785). Single-type infection was encountered in 45.0% (353/785) and multi-type infection in 17.8% (140/785), among which 98 cases had a two-type infection, 37 had a three-type infection, 2 had a four-type infection, 2 had a five-type infection and 1 case had a six-type infection. In the present study, differences in multi-type HR-HPV infection between groups with different TCT results were statistically significant. In conclusion, compared with CTC screening on its own, complementary HR-HPV testing is an effective method for screening for cervical cancer. The infection rate of HPV16, -52, -58, -33 and -18 was high among patients with cervical cytological abnormalities. Multi-type infection adds to the risk of malignancies. In Liaocheng, high-risk groups were aged 26-30 and 51-55. Attention should be paid during the screening and follow-up visits of these groups.