Correlation between immunocytochemistry of human papilloma virus L1 capsid protein and behavior of low-grade cervical cytology in Korean women

Utility of human papillomavirus L1 capsid protein and HPV test as prognostic markers for cervical intraepithelial neoplasia 2+ in women with persistent ASCUS /LSIL cervical cytology

Objective: Efficient and highly predictive biomarkers reflecting the prognosis of persistent atypical squamous cells of unknown significance(ASCUS) and low grade squamous intraepithelial lesion(LSIL)s are unavailable and need to be developed urgently. We aimed to develop a predictive model for diagnosis of cervical intraepithelial neoplasia(CIN)2+ by analyzing the immunocytochemical expression of the HPV L1 capsid protein in patients with persistent ASCUS and LSIL with a high risk of HPV infection. Methods: Cervical cytology samples comprising (70 ASCUS and 215 LSIL Pap smears) were analyzed. Immunocytochemical identification of the HPV L1 capsid protein in cervical cytology samples was performed. Expression levels of HPV L1 capsid protein in cervical cytology samples were measured, and the correlation between HPV L1 expression and cervical pathologic diagnosis was evaluated. The risk for CIN2+ was calculated using the results of immunocytochemistry and the HPV DNA test. Results: Negative results for HPV L1 immunochemistry test were more frequently observed in CIN2+, and expression of the HPV L1 capsid protein was higher in CIN1 or cervicitis (Fisher's exact test, p<0.05). Diagnosis rates for CIN2+ were highest for the combination of HPV L1 capsid protein immunocytochemistry, cytology and HPV test when compared with other combinations (Akaike information criterion (AIC): 191.7, Schwarz criterion(SC): 206.3, p<0.001). Conclusion: Absence of HPV L1 capsid expression and presence of HPV type 16 or 18 infection are reliable predictors of progression to CIN2+ in patients showing persistent ASCUS and LSIL.

E2/E6 ratio and L1 immunoreactivity as biomarkers to determine HPV16-positive high-grade squamous intraepithelial lesions (CIN2 and 3) and cervical squamous cell carcinoma

Objective

Human papillomavirus (HPV) 16 is the most carcinogenic HPV genotype. We investigated if HPV16 L1 capsid protein and E2/E6 ratio, evaluated by cervical cytology, may be used as biomarkers of ≥cervical intraepithelial neoplasia (CIN) 2 lesions.

Methods

Cervical specimens were obtained from 226 patients with HPV16 single infection. Using cytology specimen, L1 capsid protein and E2/E6 ratio were detected and the results were compared with those of the conventional histologic analysis of cervical tissues (CIN1–3 and squamous cell carcinoma [SCC]) to evaluate the association.

Results

The L1 positivity of CIN2/3 was significantly lower than that of normal cervical tissue (p<0.001) and SCC demonstrated significantly lower L1 positivity than CIN1 (p<0.001). The mean E2/E6 ratios of specimens graded as SCC (0.356) and CIN2/3 (0.483) were significantly lower than those of specimens graded as CIN1 (0.786) and normal (0.793) (p<0.05). We observed that area under the receiver operating characteristic curve (AUC) for E2/E6 ratio (0.844; 95% confidence interval [CI]=0.793–0.895) was higher than that for L1 immunochemistry (0.636; 95% CI=0.562–0.711). A combination of E2/E6 ratio and L1 immunocytochemistry analyses showed the highest AUC (0.871; 95% CI=0.826–0.917) for the prediction of ≥CIN2 lesions.

Conclusion

To our knowledge, this is the first study to validate HPV L1 capsid protein expression and decreased HPV E2/E6 ratio as valuable predictive markers of ≥CIN2 cervical lesions. Cervical cytology may be analyzed longitudinally on an outpatient basis with noninvasive procedures as against invasive conventional histologic analysis.

Clinicopathological implications of human papilloma virus (HPV) L1 capsid protein immunoreactivity in HPV16-positive cervical cytology

BACKGROUND

The objective of this study was to investigate the expression of human papilloma virus (HPV) L1 capsid protein in abnormal cervical cytology with HPV16 infection and analyze its association with cervical histopathology in Korean women.

MATERIAL AND METHODS

We performed immunocytochemistry for HPV L1 in 475 abnormal cervical cytology samples from patients with HPV16 infections using the Cytoactiv(®) HPV L1 screening set. We investigated the expression of HPV L1 in cervical cytology samples and compared it with the results of histopathological examination of surgical specimens.

RESULTS

Of a total of 475 cases, 188 (39.6%) were immunocytochemically positive and 287 (60.4%) negative for HPV L1. The immunocytochemical expression rates of HPV L1 in atypical squamous cells of unknown significance (ASCUS), low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), and cancer were 21.8%, 59.7%, 19.1%, and 0.0%, respectively. LSIL exhibited the highest rate of HPV L1 positivity. Of a total of 475 cases, the multiple-type HPV infection rate, including HPV16, in HPV L1-negative cytology samples was 27.5%, which was significantly higher than that in HPV L1-positive cytology samples (p = 0.037). The absence of HPV L1 expression in ASCUS and LSIL was significantly associated with high-grade (≥ cervical intraepithelial neoplasia [CIN] 2) than low-grade (≤ CIN1) histopathology diagnoses (p < 0.05), but was not significantly different between HPV16 single and multiple-type HPV infections (p > 0.05). On the other hand, among 188 HPV L1-positive cases, 30.6% of multiple-type HPV infections showed high-grade histopathology diagnoses (≥ CIN3), significantly higher than the percentage of HPV16 single infections (8.6%) (p = 0.0004) CONCLUSIONS: Our study demonstrates that the expression of HPV L1 is low in advanced dysplasia. Furthermore, the absence of HPV L1 in HPV16-positive low-grade cytology (i.e., ASCUS and LSIL) is strongly associated with high-grade histopathology diagnoses. The multiplicity of HPV infections may have an important role in high-grade histopathology diagnoses (≥ CIN3) in HPV L1-positive cases.

HPV L1 detection discriminates cervical precancer from transient HPV infection: a prospective international multicenter study

The benefits of cytology-based cervical cancer screening programs in reducing morbidity and mortality are well recognized. Especially, overtreatment of human papillomavirus (HPV) high-risk positive early dysplastic lesions may have a negative impact on reproductive outcomes for fertile women. To optimize the clinical management an objective standard is needed to distinguish precancer that requires treatment, from spontaneously resolving HPV infections. In the current study, we examined the prognostic relevance of HPV-L1 capsid protein analysis with Cytoactiv in an international prospective multicenter study including 908 HPV high-risk positive early dysplastic lesions (LSIL/HSIL) during a follow-up period of 54 months. The clinical end points of the study were histologically confirmed CIN3+ as progression, CIN1/2 for stable disease and repeated negative Pap smears as spontaneous clinical remission. The difference of the clinical outcome of HPV-L1-negative and HPV-L1-positive cases was statistically highly significant (P-value<0.0001) independent of the classification as mild dysplasia (LSIL) and moderate dysplasia (HSIL). Of the HPV-L1-negative HPV high-risk positive mild/moderate dysplasias 84% progressed to CIN3, as compared with only 20% of the HPV-L1-positive cases. The data from our study show that HPV-L1 detection allows to identify transient HPV infections and precancerous lesions within the group of HPV high-risk positive early dysplastic lesions. The high progression rate of HPV-L1-negative mild and moderate dysplasia emphasizes the precancerous nature of these lesions. A close follow-up with colposcopy and histological evaluation is advisable and removal of these lesions should be considered. The low malignant potential of HPV-L1-positive cases, however, indicates transient HPV infection, justifying a watch and wait strategy with cytological follow-up, thus preventing overtreatment especially for women in their reproductive age.