Triage of women with ASCUS and LSIL cytology

BACKGROUND.

The identification of a small percentage of high‐grade cervical intraepithelial neoplasias (HGCIN) among patients with minor cytological abnormalities (atypical squamous cells of undetermined significance [ASCUS] and/or low‐grade squamous intraepithelial lesions [LSIL] group) is a major problem in cytology‐based cervical cancer screening. The authors investigated the efficacy of p16^INK4a as a biomarker to identify samples of patients with HGCIN among those with an ASCUS or LSIL result in Papanicolaou cytology.

METHODS.

Consecutive liquid‐based cytology specimens of 137 ASCUS and 88 LSIL results were selected from gynecologists who adopted a triage regimen with biopsy under colposcopy 2 months later, independent of the p16^INK4a result. p16^INK4a stained slides were prepared and independently read by 2 observers, who used a recently described score to categorize p16^INK4a stained squamous cells. The endpoint of the study was detection of a biopsy‐confirmed HGCIN.

RESULTS.

The overall sensitivity and specificity of p16^INK4a positive cells with a nuclear score >2 for diagnosis of HGCIN in ASCUS and LSIL cases combined was 96% and 83%, respectively. The sensitivity and specificity in the ASCUS group was 95% and 84%, and 100% and 81% in the LSIL group, respectively. Two observers had a high concordance in assessing p16^INK4a stained cells (κ value of 0.841).

CONCLUSIONS.

These data suggested that the use of p16^INK4a as a biomarker combined with nuclear scoring of p16^INK4a positive cells in cervical cytology to triage ASCUS and/or LSIL cases allows identification of HGCIN with good sensitivity and specificity. Cancer (Cancer Cytopathol) 2007. © 2006 American Cancer Society.     

Evaluation of cervical cone biopsies for coexpression of p16INK4a and Ki-67 in epithelial cells

Diffuse overexpression of p16(INK4a) in basal and parabasal cells of cervical epithelium is a hallmark of human papillomavirus-mediated transformation. Focal p16(INK4a) expression is occasionally observed in nondysplastic epithelium. In normal cells, expression of p16(INK4a) triggers cell cycle arrest. However, cells undergoing transformation in intraepithelial lesions actively proliferate. To prove that the different expression patterns of p16(INK4a) , i.e., focal versus diffuse, reflect biologically different entities, we hypothesized that p16(INK4a) -positive cells in epithelia displaying focal p16(INK4a) expression pattern do not coexpress proliferation-associated Ki-67 protein, while p16(INK4a) -positive cells in lesions with diffuse p16(INK4a) expression may do. A total of 138 cervical cone biopsies were stained for the expression of p16(INK4a) and Ki-67 using a primary antibody cocktail. All metaplastic lesions (n = 21) displayed focal staining for p16(INK4a) , and in all of these lesions p16(INK4a) -positive cells were found to be negative for Ki-67 expression. Diffuse expression of p16(INK4a) was observed in 12/21 (57.1%) cervical intraepithelial neoplasia (CIN) 1 lesions, all of them simultaneously showed Ki-67 immunoreactivity in a large proportion of p16(INK4a) -positive cells. Seventeen of 23 (73.9%) CIN2 lesions and all 27 (100%) CIN3/carcinoma in situ (CIS) as well as all 46 (100%) carcinoma cases displayed diffuse and combined expression of p16(INK4a) and Ki-67. Coexpression of Ki-67 and p16(INK4a) in the same cell is entirely restricted to cervical lesions displaying diffuse p16(INK4a) expression, whereas in lesions with focal p16(INK4a) expression, p16(INK4a) -expressing cells are negative for Ki-67. Thus, diffuse expression of p16(INK4a) reflects lesions with proliferation-competent cells, while p16(INK4a) -expressing cells associated with focal expression patterns are cell cycle arrested.     

Good performance of p16/ki‐67 dual‐stained cytology for surveillance of women treated for high‐grade CIN

Women treated for high‐grade cervical intraepithelial neoplasia (CIN) are at risk of recurrent CIN Grade 2 or worse (rCIN2+). Currently, posttreatment monitoring is performed using cytology or cytology/high‐risk (hr)HPV cotesting. This study aimed to evaluate the performance of p16/Ki‐67 dual‐stained cytology (p16/Ki‐67) for posttreatment monitoring. Three hundred and twenty‐three women treated for high‐grade CIN in the SIMONATH study underwent close surveillance by cytology, hrHPV and DNA methylation marker testing up to 12 months posttreatment. Histological endpoints were ascertained by colposcopy with biopsy at 6 and/or 12 months. p16/Ki‐67 dual‐staining was performed on residual liquid‐based cytology samples obtained at, or shortly before biopsy collection. Clinical performance estimates of cytology, hrHPV, p16/Ki‐67 testing and combinations thereof for the detection of rCIN2+ were determined and compared to each other. Sensitivity of p16/Ki‐67 for rCIN2+ (69.2%) was nonsignificantly lower than that of cytology (82.1%; ratio 0.84, 95% CI: 0.71–1.01), but significantly lower than that of hrHPV testing (84.6%; ratio 0.82, 95% CI: 0.68–0.99). Specificity of p16/Ki‐67 for rCIN2+ (90.4%) was significantly higher compared to both cytology (70.8%; ratio 1.28, 95% CI: 1.19–1.37) and hrHPV testing (76.2%; ratio 1.19, 95% CI: 1.12–1.26). Overall, hrHPV testing showed very high sensitivity, along with a good specificity. When considering cotesting, combined p16/Ki‐67/hrHPV testing showed rCIN2+ sensitivity comparable to cytology/hrHPV cotesting (87.2% vs. 89.7%; ratio 0.97, 95% CI: 0.92–1.03), but with significantly increased specificity (74.2% vs. 58.1%; ratio 1.28, 95% CI: 1.19–1.38). Thus, when considered in combination with hrHPV, p16/Ki‐67 might be an attractive approach for surveillance of women treated for high‐grade CIN.     

Triaging HPV‐positive women with normal cytology by p16/Ki‐67 dual‐stained cytology testing: Baseline and longitudinal data

Primary human papillomavirus (HPV)‐based screening results in a 2–5% lower specificity for cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) compared to Pap cytology. To identify HPV‐positive women with CIN2+, we retrospectively evaluated the cross‐sectional and longitudinal performance of p16/Ki‐67 dual‐stained cytology in HPV‐positive women with normal cytology participating in population‐based cervical screening. Conventional Pap cytology specimens of 847 of these women derived from the VUSA‐Screen study were dual‐stained for p16/Ki‐67. Cross‐sectional clinical performance in detecting CIN3 or worse (CIN3+), and CIN2+ was compared to that of baseline HPV genotyping. Moreover, 5‐year cumulative incidence risks (CIR) for CIN3+ (CIN2+) were determined. The sensitivity of p16/Ki‐67 dual‐stained cytology for CIN3+ (CIN2+) was 73.3% (68.8%) with a specificity of 70.0% (72.8%). HPV16/18 genotyping showed a sensitivity for CIN3+ (CIN2+) of 46.7% (43.8%), with a specificity of 78.3% (79.4%). The 5‐year CIR for CIN3+ in HPV‐positive women with normal cytology was 6.9%. Testing these women with p16/Ki‐67 dual‐stained cytology resulted in a significantly lower CIN3+ 5‐year CIR of 3.3% (p = 0.017) in case of a negative test result. A negative HPV16/18 genotyping test result also led to a lower 5‐year CIN3+ CIR of 3.6%. p16/Ki‐67 dual‐stained cytology detects more than 70% of underlying CIN3+ lesions in HPV‐positive women with normal cytology at baseline and is therefore suitable for triaging these women to colposcopy. Furthermore, the CIN3+ 5‐year CIR of 3.3% after a negative dual‐stain result is significantly lower compared to the 5‐year CIR of 6.9% in women without p16/Ki‐67 dual‐stained cytology triage.     

Triaging borderline/mild dyskaryotic Pap cytology with p16/Ki-67 dual-stained cytology testing: cross-sectional and longitudinal outcome study

Background:

Women with borderline/mildly dyskaryotic (BMD) cytology smears are currently followed up with repeat testing at 6 and 18 months. The objective of this study is to analyse the cross-sectional and longitudinal performance of p16/Ki-67 dual-stained cytology for the detection of cervical intraepithelial neoplasia (CIN) grade 3 or worse (CIN3+) and CIN2+ in women with BMD, and to compare the results with baseline human papillomavirus (HPV) testing.

Methods:

Conventional Pap cytology specimens of 256 women with BMD were dual stained for p16/Ki-67 retrospectively, and compared with baseline HPV results and long-term follow-up results.

Results:

p16/Ki-67 dual-stained cytology showed a sensitivity of 100%, a specificity of 64.4% and a negative predictive value (NPV) of 100.% for CIN3+. Human papillomavirus testing demonstrated similar sensitivity (96.3%), and NPV (99.1%), but a significantly lower specificity (57.6% P=0.024) for CIN3+. Sensitivity, specificity and NPV for CIN2+ of dual-stained cytology were 89.7%, 73.1% and 95.1%, respectively, which was similar when compared with HPV testing. Dual-stained cytology showed a significant lower referral rate than HPV testing (43.6% vs 49.1% P=0.043). During long-term follow-up, no CIN3+ lesions developed in HPV-positive, dual-stained negative women.

Conclusions:

Comparable sensitivity and NPV of dual-stained cytology for CIN3+, combined with a significantly higher specificity, makes p16/Ki-67 dual-stained cytology a viable alternative to HPV testing for triaging BMD.     

Diagnostic value of p16INK4A,Ki‐67, and human papillomavirus L1 capsid protein immunochemical staining on cell blocks from residual liquid‐based gynecologic cytology specimens

BACKGROUND:

This study was conducted to evaluate the reliability and role of cell block preparations in the diagnosis of neoplastic and preneoplastic lesions of the cervix and to improve the value of cell block preparations in diagnosing and predicting the prognosis of cervical lesions through immunostaining of p16INK4A (p16), Ki‐67, and human papillomavirus (HPV) L1 capsid protein (HPV L1).

METHODS:

In total, 138 specimens were diagnosed on liquid‐based cytology (LBC) and cell block preparations, and 63 specimens were subjected subsequently to tissue follow‐up and immunostaining for p16, Ki‐67, and HPV L1 on cell block sections.

RESULTS:

In 42 specimens that were diagnosed as low‐grade squamous intraepithelial lesion, high‐grade squamous intraepithelial lesion (HSIL), and squamous cell carcinoma (SCC) on cell blocks, 38 specimens (90.5%) were confirmed by histopathologic reports, and there was slightly better than 81.6% agreement between LBC and tissue follow‐up. Immunointensity and cells that were positive for p16 were enhanced according to increased pathologic grade and differed statistically between cervical intraepithelial neoplasia 1 (CIN‐1) and CIN‐2/CIN‐3 as well as SCC. The positive rates of HPV L1 decreased gradually according to the severity of cervical neoplasia, and HPV L1/p16 expression patterns were related to the severity of cervical lesions.

CONCLUSIONS:

The cell block preparation technique was complementary to LBC, and the authors concluded that the application of LBC combined with cell block preparations may improve the diagnostic accuracy of cytology. Immunostaining for p16 and Ki‐67 on cell block preparations can help to improve the diagnostic accuracy of HSIL and SCC. A combined expression pattern of p16 and HPV L1 may serve as a valuable index for predicting prognosis and follow‐up of cervical dysplastic lesions. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.     

Combined p16INK4a and human papillomavirus testing improves the prediction of cervical intraepithelial neoplasia (CIN II-III) in Thai patients with low-grade cytological abnormalities

Thailand is in the process of developing a national cervical screening program. This study examined p16INK4a staining and HPV prevalence in abnormal cervical samples with atypical squamous cells of undetermined significance (ASCUS) and low-grade squamous intraepithelial lesion (LSIL), to evaluate the efficacy of combined HPV and p16INK4a detection to predict CIN II-III. Totals of 125 ASCUS and 87 LSIL cases were re-evaluated by Pap test and cervical cells of ASCUS and LSIL cases were prepared on slides for p16INK4a detection by immunocytochemistry. HPV genotyping of DNA extracts was performed by GP5+/6+ PCR and reverse line blot hybridization. Histopathologic tests were performed to identify cervical lesion. Total of 212 cases were diagnosed to normal (20), ASCUS (112), LSIL (78) and HSIL (2). HPV was detected in ASCUS (49/112, 43.8%), LSIL (60/78, 76.9%) and HSIL (2/2, 100%) cases. The majority of HPV positive samples typed for high-risk HPV. 55.7% (107/192) of abnormal cases (ASCUS, LSIL and HSIL) were positive p16INK4a. For the 111 HPV DNA positive cases, 34 of 49 (69.4%) ASCUS cases and 49 of 60 (81.7%) LSIL cases were p16INK4a positive. 140 biopsies were taken and histological classified: CIN negative (65 cases), CIN I (56 cases) and CIN II-III (19 cases). HPV DNA detection predicted CIN II-III with sensitivity and specificity of 84% and 49%, whereas p16INK4a staining showed higher sensitivity (89.5%) and specificity (56.2%). The prediction of CIN II-III was significantly better by combination of positive HPV DNA and p16INK4a with 93.8% sensitivity and 59.2% specificity. Detection of HPV DNA combined with p16INK4a in cervical cells can predict CIN II-III and may improve the screening diagnosis of Thai women at risk for CIN II-III or cancer.     

高危型HPV负荷量和p16INK4A蛋白监测评估宫颈锥切术治疗CIN

[目的]评价高危型人乳头状瘤病毒HPV负荷量的检测和p16INK4A蛋白的表达在预测宫颈上皮内瘤变(CIN)宫颈锥切术后残存病变或复发中的意义.[方法]回顾性分析142例2008年10月至2010年12月因CIN行宫颈锥形切除术治疗患者的临床资料.所有患者均于宫颈锥形切除术前6个月以内和术后6～12个月进行HPV负荷量检测,并采用免疫组化方法检测HPV DNA阳性患者宫颈细胞中p16INK4A蛋白表达.[结果]宫颈锥切术前,随着CIN级别的上升,HPV负荷量以及p16INK4A蛋白表达均明显增强(P＜0.05).但在宫颈锥切术后,HPV负荷量和p16INK4A蛋白表达明显降低,宫颈锥切术前和术后两者之间差异有统计学意义(P＜0.05).[结论] HPV负荷量持续增高和p16INK4A蛋白持续呈强阳性是宫颈锥切术后发生残存病变或复发的高危因素,在监测HPV负荷量的同时检测p16INK4A蛋白的表达,对判断宫颈锥切术后发生残存病变或复发有重要意义.