p16(INK4a) immunocytochemistry in liquid-based cervical cytology: is it feasible for clinical use?

A consecutive series of 118 samples from patients referred to colposcopy assessment and follow-up with cytology and biopsies were analysed with immunocytochemical staining to determinate the expression of p16(INK4a). Accumulation of p16(INK4a) antigen has been proposed as a biomarker helpful for the identification of dysplastic cervical cells. In our study all benign cases were negative for p16(INK4a), while more than half of the high grade lesions showed moderate or strong reactivity. There was a correlation between CIN grade and p16(INK4a) expression levels with more advanced lesions showing stronger reactivity. The correlation between p16(INK4a) immunoreactivity and the severity of cytological abnormality was stronger, when the diagnosis was based on simultaneous routine cytology (p<0.001, chi(2) exact test for trend). There was no or weak reactivity in benign cases, as well as almost all low-grade lesions, while two thirds of high-grade lesions showed moderate or strong staining for p16(INK4a) antigen. Thus p16(INK4a) expression analysis yielded information which is consistent with results from the histopathology and is a simple way of emphasizing the presence of premalignant cell reactive atypias. This staining can be applied to cytological samples, and might be a complement prognostic procedure in order to find women at risk for cervical cancer.

A comparison of liquid-based cytology and Pap smear as a screening method for cervical cancer.

The implementation of population-based screening for cervical cancer with Pap smear in the early sixties was set to detect and treat precancerous lesions, hopefully preventing a subsequent invasive cervical cancer. Epidemiological data indicate that organized screening has a major impact on morbidity and mortality from cervical cancer. The limited sensitivity of a single smear necessitates repeated smears in organized program. It is suggested that liquid-based cytology improves the sensitivity. The aim of this split-sample study was to compare ThinPrep liquid-based cytology with conventional Pap smear, relying on a laboratory with long-term experience of the latter. In total, 137 women with atypical Pap smear in population-based cervical screening were enrolled for the split-sample study. The performance of both techniques (ThinPrep liquid-based cytology and conventional Pap smear) were compared and validated by a histological follow-up. Women without representative histological biopsy were excluded from the study. Pap smear had sensitivity for detection of CIN2-3 of 47% compared to 66% for liquid-based material. The concordance of the two sampling techniques with the histological diagnosis was 37% and 53%, respectively, this difference being statistically significant. The proportion of reports on atypical squamous cells of undetermined significance (ASCUS) was significantly less in the liquid-based material, 4.3% compared to 8% of the conventional smears. This improved sensitivity in combination with the possibility to perform reflex testing such as HPV DNA or p16 immunocytochemistry without renewed sampling gives ThinPrep a substantial advantage and makes the liquid-based technique interesting.

Expression of E6/E7 mRNA from 'high risk' human papillomavirus in relation to CIN grade, viral load and p16INK4a.

Detection of E6/E7 mRNA expression with real-time nucleic acid sequence-based amplification assay (NASBA) method (PreTect HPV-Proofer) from high-risk types of human papillomaviruses (HR-HPV) were compared with the presence of viral load, determined with quantitative real-time PCR in 80 cervical samples. Results regarding positivity and typing were in agreement using the two methods. However, there was no correlation between viral loads for HPV 16 or 18/45 and oncogene expression. Among 15 women with low grade atypia detected at a population-based cytology screening, and scored as 'within normal limits' according to histopathology, 14% were positive for oncogene expression, whereas 71% were HR-HPV positive. A correlation was observed between HR-HPV oncogene expression and high scores of p16(INK4a) positivity. Since HPV-Proofer detects full-length E6/E7 mRNA, a positive result should correlate with presence of integrated HPV, loss of HPV replication and stabilized E6/E7 full-length mRNA expression. Such expression from integrated HR-HPV generates a high and stable expression of full-length E6 proteins, which explains why a positive HPV-Proofer result was independent of viral load and correlate with high expression of p16(INK4a). Thus, E6/E7 oncogene expression analysis yielded information, which is consistent with and will complement the results from a real-time PCR method in a clinical prognostic procedure.

Miniconization procedure with C-LETZ conization electrode for treatment of cervical intraepithelial neoplasia: a Swedish study.

BACKGROUND: Since 1989 large loop excision of the transformation zone (LLETZ) has become the treatment of choice for cervical intraepithelial neoplasia in many colposcopy clinics. This method has limitations however, in that the resection margins of the cone produced by LLETZ cannot give conclusive histological reassurance, because of thermal injury in 5 30% of the specimens. Furthermore, LLETZ are often taken in several sections, which makes the histopathological examination unnecessarily difficult. As a new and single treatment without these limitations, conization with the contoured loop excision of the transformation zone (C-LETZ) electrode was investigated in the present study. Material and methods. One hundred and seventy-four patients with CIN were treated with the C-LETZ electrode during 12 months at the Gynaecological Department, Karolinska University Hospital, Huddinge. The inclusion criteria were a histological diagnosis of CIN II-III, or persistent CIN I. RESULTS: Eighty-six per cent of the patients had a complete excision according to histological findings, and 12% had an incomplete excision. The frequency of incomplete excisions increased with the severity of the CIN but were found in all groups of patients: 1 (3%) in CIN I, 5 (12%) in CIN II, and 12 (17%) in CIN III. The resection margins and histological diagnoses were certain in 98% of the cases. A cure rate of 90% was observed. Conclusions. Miniconization with the C-LETZ electrode makes it possible to individualize the size of the minicones and produce the minicones as one-piece specimens for histopathological assessment. Our findings confirm that this method is a reproducible, safe, and economical way to treat CIN with a low rate of morbidity in a hospital outpatient setting.