The Accuracy of p16/Ki-67 and HPV Test in the Detection of CIN2/3 in Women Diagnosed with ASC-US or LSIL

Abstract

The objective of this study was to compare the accuracies of double staining for p16/Ki-67 and the molecular test for high-risk HPV (hr-HPV) to identify high-grade cervical intraepithelial neoplasia (CIN2/CIN3) in women with cervical cytology of atypical squamous cells of undetermined significance (ASC-US) and low-grade squamous intraepithelial lesion (LSIL). Data were collected from 201 women who underwent cervical cytology screening in the Barretos Cancer Hospital and their results were categorized as ASC-US (n=96) or LSIL (n=105). All patients underwent colposcopy with or without cervical biopsy for diagnosis of CIN2/CIN3. The hr-HPV test (Cobas 4800 test) and immunocytochemistry were performed to detect biomarkers p16/Ki-67 (CINtec PLUS test). Two samples (1 ASC-US/1 LSIL) were excluded from the analysis due to inconclusive results of the histologic examination. There were 8 cases of CIN2/CIN3 among 95 women with ASC-US (8.4%), and 23 cases of CIN2/CIN3 among 104 women with LSIL (22.1%). In the group of women with ASC-US, the sensitivity and specificity in diagnosing CIN2/CIN3 were 87.5% and 79.5% for the HPV test and 62.5% and 93.1% for p16/Ki-67. Among women with LSIL, the sensitivity and specificity in the diagnosis of CIN2/CIN3 were 87% and 34.7% for the HPV test and 69.6% and 75.3% for immunocytochemistry. Superior performance was observed for p16/Ki-67 double staining, especially among women under 30 for whom the test had an area under the ROC curve of 0.762 (p<0.001). Both p16/Ki-67 double staining and the hr-HPV DNA test had similar performance in predicting high-grade cervical intraepithelial neoplasia among women with ASC-US. The best performance was observed in women aged >30 years. In younger women (≤30 years) with LSIL, p16/Ki-67 had greater accuracy in identifying precursor lesions. Among women >30 years diagnosed with LSIL, the two methods showed similar performance.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Flowchart of the colposcopic examination and research p16/Ki-67 and hr-HPV.

ASC-US: atypical squamous cells of undetermined significance; LSIL: low-grade squamous intraepithelial lesion; EC: endocervical curettage.

Fig 2. Examples of positive tests for Ki-67 (red) and p16 (brown).

(A) and (D), 200x magnification; (B) and (C), 400x magnification.

Fig 3. Correlation between cervical cytology and colposcopy and histological findings.

CIN1, 2, 3: cervical intraepithelial neoplasia grade 1, 2 and 3; ASC-US: atypical squamous cells of undetermined significance; LSIL: low-grade squamous intraepithelial lesion. (*) Two cases with inconclusive biopsies (1 ASC-US and 1 LSIL) were excluded.

Fig 4. hr-HPV test according to the colpo-histological diagnosis.

HPV-16: positive cytological samples for subtype HPV-16. HPV-18: positive cytological samples for subtype HPV-18. Twelve Other HPV subtypes: positive cytology samples for one or more subtypes of HPV belonging to group 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68. CIN 1, 2, 3: cervical intraepithelial neoplasia grade 1, 2 and 3.