Moderate variation of the oncogenic potential among high-risk human papillomavirus types in gynecologic patients with cervical abnormalities

Increased human papillomavirus viral load is correlated to higher severity of cervical disease and poorer clinical outcome: A systematic review

Cervical cancer is the fourth most common cancer in women worldwide and is caused by persistent infection with high-risk types of human papillomavirus (HPV). HPV viral load, the amount of HPV DNA in a sample, has been suggested to correlate with cervical disease severity, and with clinical outcome of cervical cancer. In this systematic review, we searched three databases (EMBASE, PubMed, Web of Science) to examine the current evidence on the association between HPV viral load in cervical samples and disease severity, as well as clinical outcome. After exclusion of articles not on HPV, cervical cancer, or containing clinical outcomes, 85 original studies involving 173 746 women were included. The vast majority (73/85 = 85.9%) reported that a higher viral load was correlated with higher disease severity or worse clinical outcome. Several studies reported either no correlation (3/85 = 3.5%), or the opposite correlation (9/85 = 10.6%); possible reasons being different categorization of HPV viral load levels, or the use of specific sampling methods. Despite variations in study design and populations, the above findings suggest that HPV viral load is correlated to clinical outcome, and may become an important biomarker for treatment selection and response monitoring for cervical cancer.

Bladder cancer-associated protein is suppressed in human cervical tumors

Bladder cancer-associated protein (BLCAP) is downregulated in bladder cancer and has been identified as a prognostic biomarker for human bladder cancer. We previously reported that BLCAP mRNA is decreased in cervical cancer tissues, and overexpression of BLCAP was found to inhibit cell growth and induce apoptosis in the human cervical cancer HeLa cell line To investigate the BLCAP protein expression in cervical cancer and its potential clinical indications, we developed a polyclonal antibody against human BLCAP to assess the BLCAP protein expression in 30 cervical cancer tissues and 30 non-tumor cervical tissues from patients. Western blotting data showed that a single band of recombinant protein was probed by antiserum of BLCAP and no band was probed by pre-immune serum. BLCAP expression was significantly downregulated in cervical carcinoma tissues compared with its expression in the non-tumor cervical tissues. Moreover, cervical carcinoma tissues from patients with stage III-IV had significantly lower BLCAP expression percentage compared with stage I-II. Similarly, a significantly lower BLCAP expression percentage was observed in moderately/poorly differentiated tumor tissues and in the tumor tissues from patients with lymphatic metastasis (LM) compared with well-differentiated tumor tissues and non-LM patients, respectively. Our results suggest that decreased BLCAP protein expression is associated with poor prognosis and it could be a potential bio-index to predict cervical tumor patient outcome.

Genotyping of human papillomavirus in triaging of low-grade cervical cytology

OBJECTIVE

The objective of the study was to evaluate whether typing of human papillomavirus (HPV) among women with low-grade cervical cytology can improve the ability to identify women with cervical cancer or cervical intraepithelial neoplasia grade III (CIN III or worse).

STUDY DESIGN

A total of 1595 women with low-grade cervical cytology participating in a randomized implementation trial of HPV triaging using Hybrid Capture II were also HPV genotyped and CIN III or worse predictive values evaluated.

RESULTS

HPV 16 was detected in 57% of cases with CIN III or worse but only among 24% of all tested women. Testing for the 3 HPV types with highest risk (HPV16/31/33) detected 77% of CIN III or worse, with 36% of women testing positive. Positivity for the other high-risk HPV types had a decreased risk for CIN III or worse.

CONCLUSION

Different high-risk HPV types confer different risks for the presence of CIN III or worse, implying that HPV genotyping could be useful for the optimization of triaging strategies.

HPV genotype distribution according to severity of cervical neoplasia

OBJECTIVE

To analyse the HPV genotype profile and the presence of multiple HPV infections according to severity of cervical intraepithelial neoplasia.

METHODS

From a population of 424,143 women in Norway, we included all women (n=643) with histologically confirmed cervical intraepithelial neoplasia grade 2 or higher (CIN2+) and evaluable HPV test during 2005 and 2006. Histology revealed CIN2 in 135 women, CIN3/ACIS in 495, and invasive carcinoma in 13 women. HPV genotyping was performed on cell suspensions from cervix by linear array which differentiates 37 HPV genotypes.

RESULTS

HPV was detected in 98.4% (633/643) of the women, of whom 52.5% (338/643) were infected with more than one HPV genotype. HPV16 was most common, being detected in 51.2% (329/643) of all cases, followed by HPV31, 33, 52, 18, and 51. Overall, HPV 16 or 18 were detected in 58.0% (373/643), with 34.7% (223/643) without concurrence of other high-risk genotypes. HPV16 and HPV33 as single infections were more common in women with CIN3+ as compared to CIN2 (age-adjusted odds ratio=5.93, 95% CI=2.73-12.87, and age-adjusted odds ratio=4.53, 95% CI=1.42-14.46, respectively). Concurrent infection with other HPV genotypes did not significantly alter the associations to CIN3+ for HPV16 or HPV33. A single HPV infection, other than HPV16, 18, 31, or 33, was used as the reference. HPV18 or multiple HPV infections not including HPV16 or HPV33 were not associated with the severity of cervical neoplasia.

CONCLUSION

HPV16 and HPV33 appear to have a higher oncogenic potential than other HPV genotypes.

HPV type-specific risks of high-grade CIN during 4 years of follow-up: a population-based prospective study

We followed a population-based cohort of 5696 women, 32–38 years of age, by registry linkage with cytology and pathology registries during a mean follow-up time of 4.1 years to assess the importance for CIN2+ development of type-specific HPV DNA positivity at baseline. HPV 16, 31 and 33 conveyed the highest risks and were responsible for 33.1, 18.3 and 7.7% of CIN2+ cases, respectively. Women infected with HPV 18, 35, 39, 45, 51, 52, 56, 58, 59 and 66 had significantly lower risks of CIN2+ than women infected with HPV 16. After adjustment for infection with other HPV types, HPV types 35, 45, 59 and 66 had no detectable association with CIN2+. In summary, the different HPV types found in cervical cancer show distinctly different CIN2+ risks, with high risks being restricted to HPV 16 and its close relatives HPV 31 and HPV 33.

Functional analysis of bladder cancer-related protein gene: a putative cervical cancer tumor suppressor gene in cervical carcinoma

Our previous study has suggested thatthe bladder cancer-associated protein gene (BLCAP) was among the differentially expressed genes in cervical cancer. We confirm here that BLCAP is expressed in all noncancerous cervical tissues (10/10), but it is greatly lost in primary cervical cancer tissue (31/39). In order to further investigate the functional roles of BLCAP, we stably transfected BLCAP cDNA into HeLa cells. The HeLa cells expressing BLCAP show reduced cell growth and clone genicity compared to the vector-transfected cognate cells. BLCAP expression in HeLa cells leads to growth arrest and significantly enhanced apoptosis in vitro and reduced tumor formation in vivo. Thus, BLCAP might be a potential tumor suppressor gene in cervical carcinoma.

Duration of HPV-associated risk for high-grade cervical intraepithelial neoplasia

OBJECTIVE

To evaluate the duration of high-risk HPV-associated cancer risk.

STUDY DESIGN

Patients who had had a routine diagnostic Hybrid Capture Tube Test (HCT) due to squamous cell abnormalities of the uterine cervix were followed-up until the endpoint of histologically diagnosed cervical intraepithelial neoplasia (CIN).

RESULTS

Six hundred and thirty-eight women were followed during a cumulative follow-up of 16,423 patient months. The adjusted relative risk associated with the positive HR-HCT test for high-grade CIN/52.0 (20.9-19.2)/ proved to be higher than that of the cytological atypia/5.44 (2.52-11.77)/. At the end of the 30 months of follow-up the crude and adjusted risks for CIN2+ were 214.3 (28.4-1615.7) and 196.7 (25.4-1525.2), respectively in the HPV 16/18 group, and after 30 months, the crude and adjusted RR decreased to 57.6 (10.4-318.9) and 29.2 (5.02-170.0). In the groups of other high-risk types and possibly high-risk types the general tendency was the same. However, new CIN2+ cases were not detected after the 30th month of follow-up in these later groups.

CONCLUSIONS

HPV16/18 associated relative risk is nearly 200 times higher than that of the HPV negative population and an outstanding risk persists with duration of about 30 months. The risk is manifested in progression to high-grade CIN lesions mainly within a 2 years interval after the first detection of HPV 16/18 infection.

Human Papillomavirus Type 16 Infections and 2-Year Absolute Risk of Cervical Precancer in Women With Equivocal or Mild Cytologic Abnormalities

BACKGROUND

The 2-year absolute risk for cervical precancer attributable to infection by human papillomavirus type 16 (HPV16), the most common and oncogenic HPV type, in the millions of women diagnosed annually with equivocal or mildly abnormal cytology has not been definitively evaluated.

METHODS

Baseline cervical specimens of 5060 women with equivocal (atypical squamous cells of undetermined significance [ASCUS]) or mildly abnormal (low-grade squamous intraepithelial lesion [LSIL]) cytology were tested for HPV DNA using Hybrid Capture 2 (HC2) and type-specific L1 consensus primer polymerase chain reaction. We calculated absolute risks with 95% confidence intervals (CIs) for cumulative diagnosis, during the 2-year study period, of cervical intraepithelial neoplasia grade 3 (CIN3) (n = 535) or cancer (n = 7) (collectively referred to as > or = CIN3) and compared risk by HPV16 status and by other oncogenic HPV types using logistic regression. All statistical tests were two-sided.

RESULTS

The baseline prevalences of HPV16 in women with ASCUS or LSIL cytology were 14.9% and 21.1%, respectively. Women with ASCUS or LSIL cytology who were HPV16 DNA positive at baseline had 2-year cumulative absolute risks for > or = CIN3 of 32.5% (95% CI = 28.4% to 36.8%) and 39.1% (95% CI = 33.8% to 44.7%), respectively. By comparison, women with ASCUS who were positive by HC2 for other oncogenic HPV types combined had an 8.4% (95% CI = 6.9% to 10.4%) risk for > or = CIN3, which was similar to the risk posed by having ASCUS (risk = 8.8%, 95% CI = 7.9% to 9.8%) without knowledge of the oncogenic HPV DNA status. Women with LSILs who were positive by HC2 for other oncogenic HPV types combined had a 9.9% (95% CI = 8.0% to 12.0%) 2-year risk for > or = CIN3, which was less than the risk posed by having LSILs (risk = 15.0%, 95% CI = 13.3% to 16.9%) without knowledge of the oncogenic HPV DNA status. Together, women with ASCUS or LSILs who were HPV16-positive had the highest 2-year risk for > or = CIN3 compared with women who were HPV-negative (odds ratio [OR] = 38, 95% CI = 22 to 68; P < .001 ), fivefold greater than the increased risk in women who were positive for other oncogenic HPV types (OR = 7.2, 95%CI = 4.2 to 13, P < .001).

CONCLUSIONS

Distinguishing the high absolute risk for cervical precancer in HPV16-positive women from the lower risk posed by other oncogenic HPV types might have clinical implications.

Role of human papillomavirus (HPV) testing in the follow-up of patients after treatment for cervical precancerous lesions

OBJECTIVE

To evaluate the role of human papillomavirus (HPV) testing in post-treatment follow-up of patients after therapeutic excision of the cervix due to positive screening tests.

STUDY DESIGN

A hospital-based retrospective analysis was performed with prospective collection of patient data of women screened for cervical cancer at a Gynecologic Outpatient Clinic. Patients after therapeutic excision due to positive screening results were identified and followed up with HPV testing and serial cytology.

RESULTS

After 61 treatment for cervicalis intraepithelialis neoplasia (CIN), high-risk HPV infection was detected during the post-treatment follow-up at 18 cases (29.5%), 10 of them had persisting cytological atypia (positive predictive value (PPV): 56%), 5 developed CIN (PPV: 28%). When the HPV test was negative (43 patients) in the post-treatment period, neither CIN nor persisting cytological atypia developed (negative predictive value (NPV): 100%) during 1201 patient months (median 26 months).

CONCLUSIONS

A negative HPV test eliminates the risk of recurrent disease after treatment for CIN.