P16INK4a as an adjunct marker in liquid-based cervical cytology

Cytological screening for cervical cancer is hampered by high false negative rates. Inter-observer reproducibility needs optimizing. The potential of p16(INK4a) as a biomarker for cervical lesions was examined in a study of liquid-based cytology (LBC), HPV DNA testing by MY09/MY11 consensus PCR and type-specific PCRs and p16(INK4a) immunocytochemistry on a series of 291 patients selected from routine screening. Comparison of the number of p16(INK4a) immunoreactive cells/1,000 cells exhibited a significantly higher mean count in HSIL (8.80 +/- 1.13) than other cytological groups. The mean count of LSIL (1.09 +/- 0.18) was significantly higher than that of the negative group (0.82 +/- 0.40). ASC-H and HSIL combined showed a significantly higher mean count (6.46 +/- 1.17) than negative, ASC, ASC-US and LSIL. The mean count of immunoreactive cells/1,000 cells was significantly higher in HPV16 positive samples (3.22 +/- 0.72) than in samples containing infections with types of unknown malignant potential (0.83 +/- 0.26) or HPV negative samples (1.17 +/- 0.41). The mean count in infections with other high-risk HPV types (2.55 +/- 0.52) was significantly higher than that in HPV negative samples. Receiver-operating characteristic curves yielded a test accuracy (area under curve) of 0.76, 0.79, 0.88 and 0.95 for ASCUS, LSIL, ASC-H/HSIL and HSIL, respectively. Thresholds for 95% sensitivity were at 0.005, 0.007, 0.098 and 0.445 immunopositive cells/1,000 cells for ASCUS, LSIL, ASC-H/HSIL and HSIL, respectively. The 95% specificity threshold for the detection of HSIL was at 1.87 immunopositive cells/1,000 cells. P16(INK4a) immunocytochemistry can be used as an adjunct to LBC in cervical screening, because it has a good diagnostic accuracy to discriminate HSIL and ASC-H from other lesions. It could be used as a surrogate marker of high-risk HPV infections.     

p16INK4a在宫颈液基细胞学辅助筛查中的标记意义

目的 评价p16INK4a在宫颈液基细胞学检查中的标记意义.方法 收集74例宫颈外口和颈管的脱落细胞标本,分别进行液基细胞学检测和p16INK4a免疫细胞化学染色,并应用杂交捕获二代法检测高危人乳头瘤病毒(HR-HPV)感染.结果 74例标本中,细胞学诊断未见癌细胞或癌前病变细胞(阴性)10例,意义不明的不典型鳞状细胞(ASC-US)15例,鳞状上皮内低度病变(LSIL)28例,不除外上皮内高度病变的不典型鳞状细胞(ASC-H)5例,鳞状上皮内高度病变(HSIL)11例,鳞状细胞癌(SCC)5例.各级别病变中,HR-HPV阳性者分别为1、4、3、9、7和5例,p16INK4a免疫细胞化学染色阳性者分别为2、5、3、8、9和5例.随着宫颈病变级别的上升,HR-HPV和p16INK4a免疫细胞化学染色阳性率均增高.结论 p16INK4a免疫细胞化学染色增强了对不典型细胞的区分能力,可以提高宫颈癌筛查的准确性.     

p16INK4a免疫细胞化学检测在筛查宫颈癌中的作用

目的 探讨p16^INK4a免疫细胞化学检测在筛查宫颈癌及其癌前病变中的作用。方法 选择220例宫颈液基细胞学剩余标本,制作液基薄片进行p16^INK4a 免疫细胞化学检测,随访组织活检结果,并与高危人乳头瘤病毒（HR—HPV）DNA检测结果进行对照。结果 p16^INK4a在宫颈细胞学诊断的鳞状细胞癌（SCC）、鳞状上皮内高度病变（HSIL）、鳞状上皮内低度病变（LSIL）、非典型鳞状细胞-小除外上皮内高度病变（ASC—H）和非典型鳞状细胞-不能明确意义（ASC—US）病例的阳性表达率分别为100．0％（7／7）、92．2％（107／116）、24．3％（17／70）、100．0％（14／14）和36．4％（4／11）。150例p16^INK4a阳性者中,111例有组织活检诊断,其中宫颈上皮内瘤变（CIN）2级及以上病变者97例（87．4％）;70例p16^INK4a阴性者中,18例有组织活检诊断,无一例CIN2及以上病变。p16^INK4a在CIN2及以上病变与在CIN1之间的阳性表达率差异有统计学意义（P〈0.01）,而HR-HPV DNA的阳性率在两者之间差异无统计学意义。结论 p16^INK4a在宫颈HSIL及以上病变中高表达,有利于高危病例的筛选。     

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.     

A comparison of the clinical utility of p16(INK4a) immunolocalization with the presence of human papillomavirus by hybrid capture 2 for the detection of cervical dysplasia/neoplasia

BACKGROUND: Evidence suggests that overexpression of p16(INK4a) protein indicates infection and genomic integration of high-risk human papillomavirus (HR HPV) and predicts progression to cervical high-grade squamous intraepithelial lesions (HSILs) and carcinoma. The authors compared the ability of p16(INK4a) and HR HPV detection by Hybrid Capture 2 (HC2) to detect the presence of significant cervical disease. METHODS.: Four hundred ThinPrep specimens (100 each in 4 categories: 100 specimens that were negative for intraepithelial lesions, 100 specimens of atypical squamous cells of undetermined significance [ASC-US], 100 specimens of low-grade squamous intraepithelial lesions [LSILs], and 100 specimens of HSILs) were analyzed. p16(INK4a) protein was immunolocalized using a specific monoclonal antibody, and the detection of HR HPV in all 400 specimens was determined using HC2. RESULTS: p16(INK4a) was found to be positive in 78% of HSIL specimens, 42% of LSIL specimens, and 36% of ASC-US specimens; whereas HC2 was positive in 92% of HSIL specimens, 81% of LSIL specimens, and 45% of ASC-US specimens. In the HSIL category, the sensitivity, which was calculated using Grade 2 or greater cervical intraepithelial neoplasia as the endpoint, was 78% (50 of 66 specimens) for p16(INK4a) and 91% (60 of 66 specimens) for HC2. For LSIL, the sensitivity was 75% (3 of 4 specimens) for p16(INK4a) and 100% (4 of 4 specimens) for HC2. In the ASC-US category, the sensitivity was 89% (8 of 9 specimens) for p16(INK4a) and 100% (9 of 9 specimens) for HC2. Overall, the sensitivity for HSIL was 92% for HC2 and 78% for p16(INK4a). The specificity for HC2 was 8.3% for HSIL, 16.9% for LSIL, and 48.7% for ASC-US; whereas the specificity for p16(INK4a) was 25% in HSIL, 59.1% in LSIL, and 68.4% in ASC-US. The overall specificity was 25% for HC2 and 56% for p16(INK4a). CONCLUSIONS: Although both p16(INK4a) and HC2 may aid in the clinical management of patients with clinically significant lesions, HC2 was found to have greater sensitivity, and p16(INK4a) greater specificity. The labeling of normal cells and bacteria may preclude the use of p16(INK4a) in automated screening or nonmorphologic assays.     

Nuclear co-expression of p14ARF and p16INK4A in uterine cervical cancer-derived cell lines containing HPV

The Papanicolaou test (Pap) has been responsible for a significant reduction of cervical cancer-related morbimortality. In order to increase its sensitivity and specificity new markers have been studied and incorporated to cytological and histological methods for diagnosis for cervical cancer, such as p16INK4A that has been considered the immunocytochemical marker of choice for detection of HPV related cancers. We considered that p14ARF could be a complementary marker in order to improve the accuracy of cytological diagnosis because its genetic proximity to p16INK4A. We performed a systematic analysis of several putative cervical cancer markers in order to evaluate their performance in the detection of malignancy, in comparison with p16INK4A and p14ARF, using immunocytochemistry (ICC), immunofluorescence (IF) and Western blot analyses. Most markers were non-specific and could not discriminate HPV infected cancer cell lines from other non HPV malignant. In contrast, nuclear co-expression of p16INK4A and p14ARF was observed only in HPV-transformed cancer cell lines. Notably, in C-33A cervical cancer cells (HPV negative), p14ARF was present in the nucleoli, but p16INK4A was conspicuously absent from the nuclei of these cells. We conclude that both markers; p16INK4A and p14ARF are complementary and should be evaluated jointly in order to improve the accuracy of cytological diagnosis of cervical cancer.     

Expression of p16INK4a and MIB-1 in relation to histopathology and HPV types in cervical adenocarcinoma

A total of 101 primary cervical adenocarcinomas were analyzed for the presence of p16INK4a and MIB-1 expression in correlation with the presence of 'high-risk' types of human papillomavirus (HR-HPV) and clinical outcome.We found that adenocarcinoma grading showed a significant negative correlation to p16INK4a levels (p=0.001): i.e. we found less intense p16 staining in poorly differentiated tumors than in more highly differentiated tumors as well as a highly significant correlation between HPV infection and higher levels of p16INK4a staining (p=0.00), which was similar for different HPV-types. Tumor suppressor protein p16INK4a levels were higher in HPV positive than in HPV negative tumors. Higher levels of the proliferation marker MIB-1 were associated with poorer outcome. Higher MIB-1 levels were seen in tumors with a lower grade and higher stage at diagnosis. Moreover, MIB-1 levels seem to be higher in tumors due to infection with HPV 16 and 18 compared with HPV 45. MIB-1 may be a helpful marker in grading adenocarcinoma: a high level of expression of MIB-1 indicates a low grade of tumor, whereas high expression of p16INK4a indicates a highly differentiated of the tumor. Thus, immunostaining for p16INK4a appears to be a useful diagnostic tool for cervical adenocarcinoma.     

Evaluation of a nuclear score for p16INK4a-stained cervical squamous cells in liquid-based cytology samples

BACKGROUND: The p16INK4a gene product is overexpressed strongly in abnormal cervical epithelia and may serve as a valuable biomarker to identify abnormal cells in cervical smears or liquid-based cytology samples. METHODS: The authors performed p16INK4a immunocytochemistry to locate cells that expressed p16INK4a in liquid-based cytology samples and used a nuclear scoring system based on several morphologic criteria to interpret the degree of abnormality of these cells. RESULTS: Among 108 samples that were scored as normal in Papanicolaou-stained, parallel slides, any p16INK4a-positive cells were observed in 13 samples (12%), but only 1 of 108 samples (1%) was scored abnormal after applying nuclear scoring criteria. In the group of 52 low-grade squamous intraepithelial lesion (LSIL) samples, 19 samples (37%) were positive for any p16INK4a reactivity, but only 5 of those samples (10%) were scored abnormal after applying the nuclear score. Among the 50 high-grade squamous intraepithelial lesion (HSIL) samples, 49 samples (98%) were positive for p16INK4a and were scored as abnormal. Comparison of the scoring results of independent observers revealed good reproducibility of the nuclear score. CONCLUSIONS: The current results suggested that p16INK4a enables the location of potentially abnormal cells on liquid-based cytology samples. The nuclear score facilitated interpretation of the degree of abnormality of p16INK4a-stained cells. Thus, locating potentially abnormal cells by p16INK4a immunocytochemistry and their interpretation based on the nuclear score described here may help to identify patients with HSIL in cytologic screening programs and may represent a new approach for reducing the number of equivocal or misinterpreted cytologic specimens.     

Immunocytochemical colocalization of P16(INK4a) and Ki-67 predicts CIN2/3 and AIS/adenocarcinoma

BACKGROUND:

Although previous studies have shown that p16^INK4a and Ki‐67 are sensitive and specific markers for high‐grade lesions (≥CIN2) on cervical biopsies, limited information is available regarding the performance of a dual‐staining approach as a diagnostic adjunct in cervical cytology. We evaluated a dual p16^INK4a/Ki‐67 immunocytochemistry (ICC) assay to determine its sensitivity and specificity versus that of high‐risk HPV (HR‐HPV) in a US‐based pilot cytology study.

METHODS:

ThinPrep specimens from 122 cervical cytology specimens encompassing 23 negative (NILM), 20 ASC‐US, 22 LSIL, 17 ASCH, 22 HSIL, and 18 AGC cases were processed for multiplexed ICC staining using a CINtec Plus Kit. Dual‐positive assay results were defined based on the detection of 1 or more epithelial cells that were stained for both p16^INK4a and Ki‐67 without regard to cellular morphology. HR‐HPV testing was performed by multiplex PCR with capillary electrophoresis genotyping.

RESULTS:

Dual staining for p16^INK4a and Ki‐67 was frequently detected in HSIL and AGC but was rarely detected in NILM cases. The HR‐HPV assay showed a sensitivity of 76.2% and a specificity of 55.8% for the detection of clinically significant cervical squamous or endometrial lesions. In contrast, the colocalization of p16^INK4a plus Ki‐67 maintained a high sensitivity of 81.8% and improved specificity to 81.8% for biopsy‐confirmed CIN2/3, endocervical adenocarcinoma, or endometrial adenocarcinoma.

CONCLUSIONS:

Dual staining for p16^INK4a/Ki‐67 immunocytochemistry dramatically increased specificity and maintained high‐level sensitivity for the diagnosis of CIN2/3 or glandular lesions compared with PCR‐based testing for HR‐HPV. Cancer (Cancer Cytopathol) 2012. © 2011 American Cancer Society.     

Evaluation of a new p16(INK4A) ELISA test and a high-risk HPV DNA test for cervical cancer screening: results from proof-of-concept study

p16(INK4a), a cell cycle regulation protein, accumulates in abnormal epithelial cells infected with high-risk human papilloma virus (HPV). In immunostaining studies, p16(INK4a) has shown potential as a marker of high grade cervical intraepithelial neoplasia (CIN) and invasive cervical cancer. To evaluate its potential use in cervical cancer screening, we conducted a feasibility study to compare the performance of a new enzyme linked immunosorbant assay (ELISA) for p16(INK4a) (mtm laboratories, Heidelberg, Germany) to that of the Hybrid Capture 2 (hc2) test for high-risk HPV DNA for the detection of CIN3. Three hundred and nineteen women were referred from Western Washington Planned Parenthood clinics for colposcopy examination and cervical biopsy because of abnormal Pap test results. Cervical samples were obtained from study participants for p16(INK4a) ELISA, liquid-based cytology and hc2. The order (first and second) for obtaining samples for cervical cytology and p16(INK4a) ELISA changed with every other subject. Concentrations of p16(INK4a) protein were higher when the sample was taken before the cytology. The sensitivity of p16(INK4a) ELISA (concentration > or = 8 units/ml) taken as first sample was 90.0% for CIN3, and the sensitivity of HC2 taken as a second sample was 85%. In the same group, the specificity of p16(INK4a) ELISA (46.9%) was slightly better than hc2 (35.4%) Results from this proof-of-concept study suggest that p16(INK4a) ELISA has a similar sensitivity and slightly better specificity for CIN3 compared to hc2. These findings support proceeding with a larger study with samples from a population of women presenting for routine cytology screening.     

p16INK4a is superior to high‐risk human papillomavirus testing in cervical cytology for the prediction of underlying high‐grade dysplasia

BACKGROUND

The primary goal of this study was to compare the clinical performance of an optimized and rigorously controlled immunocytochemical (ICC) assay for p16^INK4a to high‐risk (HR) human papillomavirus (HPV) detection by polymerase chain reaction (PCR) as diagnostic adjuncts for cytology specimens from colposcopy patients.

METHODS:

The study included 403 cervical cytology specimens collected within 3 months of colposcopy. The colposcopic impression and cervical biopsy diagnosis served as the standards for correlation with cytological, p16^INK4a, and HPV data. p16^INK4a was evaluated using an immunoperoxidase‐based assay that was linear over 4 logs for the detection of HeLa‐spiked positive control cytology specimens, using a threshold for positive test results that was based on receiver operating characteristic curve analysis. HR‐HPV was detected by multiplex PCR using genotype‐specific primers.

RESULTS:

In all combined diagnostic categories (negative for intraepithelial lesion and malignancy, atypical glandular cells, atypical squamous cells of undetermined significance, atypical squamous cells cannot exclude high‐grade squamous intraepithelial lesion, low‐grade squamous intraepithelial lesion, and high‐grade squamous intraepithelial lesion), the p16^INK4a ICC and HR‐HPV assays, respectively, had sensitivity of 81.7% and 83.3% (P = .81) and specificity of 78.1% and 50.9% (P < .001) for the detection of underlying ≥grade 2 cervical intraepithelial neoplasia (CIN) lesions on biopsy. Furthermore, the positive predictive value of p16^INK4a ICC was greater than that of HR‐HPV for patients with biopsies ≥CIN‐2 (41.2% and 24.2%, respectively, P = .001).

CONCLUSIONS:

This p16^INK4a immunocytochemical assay has superior specificity but similar sensitivity to HR‐HPV testing to predict underlying high‐grade dysplastic lesions in patients who are referred for colposcopy. The determination of the overall performance characteristics of p16^INK4a immunocytochemistry, as an independent test or in combination with HPV testing in low‐risk screening populations, however, will require subsequent large‐scale prospective clinical trials. Cancer (Cancer Cytopathol) 2010. © 2010 American Cancer Society.     

Human Papillomavirus Detection and Abnormal Anal Cytology in HIV-infected Patients Using p16/Ki-67 Dual-Staining

Objective: We investigated human papillomavirus (HPV) infection and detected anal squamous intraepithelial lesions by modified liquid-based cytology (LBC) and p16/Ki67 dual-staining. Methods: Anal swabs (n=393) were collected from patients with HIV infection. Anal cells were kept in 95% ethyl alcohol for modified LBC. DNA was extracted from cells for HPV detection and genotyping using real-time PCR and reverse line blot hybridization. Results: Nine samples (2.3%) were unsatisfactory specimens, 74.8% (294/393) were negative for intraepithelial malignancies (NILM) and 22.9% (90/393) exhibited squamous intraepithelial lesions (SIL). In the latter category, 13.7% of samples (54/393) contained atypical squamous cells of undetermined significance (ASCUS), 6.9% (27/393) were classified as low-grade SIL (LSIL) and 2.3% (9/393) as high-grade SIL (HSIL). A total of 331 from 393 swab samples were suitable for detection of HPV infection. Among these, 34.1% (113/331) were positive. HPV 58 (15.9%) was the most common genotype, followed by HPV 18 (14.2%) and HPV 16 (11.5%). The severity of abnormal cells was significantly associated with HPV infection. Dual staining with p16/Ki-67 was performed on 130 samples: in 30.8% (40/130) of samples positive staining was significantly associated with severity of abnormal cells. Agreement between cytology, p16/Ki67 dual-staining and high-risk HPV detection was 100% in HSIL samples. Interestingly, eight apparently NIML cases might have contained abnormal cells, since they were positive by both p16/Ki67 dual-staining and high-risk HPV detection. Conclusion: Anal specimens screened using modified LBC with 95% ethyl alcohol solution as the fixative are suitable for screening anal precancerous lesions by cytology, HPV testing and p16/Ki-67 dual staining.     

Performance of visual inspection with acetic acid and human papillomavirus testing for detection of high‐grade cervical lesions in HIV positive and HIV negative Tanzanian women

The aim of this cross sectional study was to assess type distribution of human papillomavirus (HPV) among HIV positive and HIV negative women who underwent cervical cancer screening, and to examine the ability of visual inspection with acetic acid (VIA), the standard detection method in Tanzania, and HPV‐testing to detect cytologically diagnosed high grade lesions or cancer (HSIL+). Women from different areas in Tanzania were invited by public announcement to cervical cancer screening organized by Ocean Road Cancer Institute (Dar‐es‐Salaam). A total of 3,767 women were enrolled. Women underwent gynecological examination with collection of cervical cells for conventional cytological examination, and swab for HPV‐DNA detection (Hybrid‐Capture2) and genotyping (LiPAv2 test). Subsequently VIA was performed. The participants were also tested for HIV. HPV16, HPV52 and HPV18 were the three most common HR HPV types among women with HSIL+ cytology with prevalences of 42.9, 35.7 and 28.6%, respectively, in HIV positive women which was higher than among HIV negative women (30.2, 21.9 and 16.7%). A total of 4.5% of the women were VIA positive, and VIA showed a low sensitivity compared to HPV‐testing for detection of HSIL+. The sensitivity of VIA varied with staff VIA experience, HIV status and age. Vaccines including HPV16, HPV52 and HPV18 will likely reduce the number of HSIL+ cases independently of HIV status. The frequency of HSIL+ was high among HIV positive women, emphasizing the importance of establishing a screening program which also reaches HIV positive women. Our results highlight the importance of continuous training of staff performing VIA, and also point to the need for other screening methods such as HPV‐testing at low cost.     

Immunoreactivity of p16 in anal cytology specimens: histologic correlation

BACKGROUND: Cytology has been proposed as a potential screening tool in the evaluation of squamous anorectal disease in view of the morphologic similarities between anal and cervical squamous lesions. Previous studies have demonstrated that p16 overexpression correlates with the degree of dysplasia in the uterine cervix with promising results. Due to potential diagnostic pitfalls in anal cytology, p16 overexpression in these specimens was studied. METHODS: Patients with anorectal cytology who underwent follow-up biopsy within 1 year were selected. Forty-three anorectal cytologic specimens from 29 patients were selected. One slide of each case was destained. Avidin-biotin immunocytochemical studies with the monoclonal antibody CINtec p16(INK4a) were performed. The results of the p16 immunostaining were correlated with the histologic findings. RESULTS: Twenty-eight of the 43 cases demonstrated the presence of squamous cells immunoreactive for p16 in cytology specimens. The p16-positive cells were identified in cases of low-grade squamous intraepithelial lesion (LSIL) (n = 3 cases), high-grade squamous intraepithelial lesion (HSIL) (n = 22 cases), and invasive squamous carcinoma (n = 1 case), and in 2 cases with negative follow-up biopsies. No cell immunoreactive for p16 was found in 15 cases (5 benign cases and 10 cases with either LSIL or HSIL). The sensitivity and specificity of p16 immunoreactivity in the detection of anal intraepithelial neoplasia or carcinoma were 72% and 71%, respectively. The positive and negative predictive values were 93% and 33%, respectively. CONCLUSIONS: The presence of p16 immunoreactivity is a good predictor of dysplasia in anal specimens. However, the sensitivity and specificity of this marker are not high.     

P16/Ki-67 Dual Staining in Positive Human Papillomavirus DNA Testing for Predictive Diagnosis of Abnormal Cervical Lesions in Northeastern Thai Women

Objective: Cervical cancer screening can effectively reduce new cervical cancer cases, including in Thailand. The abnormal results are subsequently referred for colposcopy. To avoid unnecessary colposcopy, an efficient triage is still needed for validation. This study aimed to investigate the overall positivity of cytology-based screening, HPV detection, and p16/Ki-67 dual staining and evaluate different triage strategies for predictive diagnosis of abnormal cervical lesions in northeastern Thailand. Methods: Cervical cells were collected from 191 women who came for cervical screening in the gynecological outpatient department during March 2019-February 2020. Pap smear samples were classified into 6 groups including 17 atypical glandular cells (AGC), 21 atypical squamous cells of undetermined significance (ASC-US), 7 atypical squamous cells - cannot exclude HSIL (ASC-H), 26 low-grade squamous intraepithelial lesions (LSILs), 19 high-grade SILs (HSILs) and 101 no squamous intraepithelial lesion (noSIL). Polymerase chain reaction (PCR) was performed for HPV DNA detection. HPV genotyping was determined by reverse line blot hybridization. P16/Ki-67 dual staining was performed by using CINtec PLUS Cytology kit. Biopsies from abnormal screening were collected for surgical pathology classification. Results: High-risk HPV (HR-HPV) infection was 2.97%, 29.41%, 38.10%, 57.14%, 46.15% and 84.21% in noSIL, AGC, ASC-US, ASC-H, LSIL and HSIL cytology respectively. P16/ Ki-67 in noSIL, AGC, ASC-US, ASC-H, LSIL and HSIL was 0.99%, 5.88%, 9.52%, 42.86%, 26.92% and 63.16%, respectively (P-value < 0.001). Among p16/Ki-67 positive cases, 96.15% (25/26) were infected with HPV and 84.62% (22/26) were HR-HPV. The overall positivity of each and co-testing between cytology or HPV DNA testing or p16/Ki-67 dual staining was evaluated. In each cervical lesion, primary HPV DNA testing showed the highest sensitivity, but low specificity. The combined all HPV/HR-HPV with p16/Ki-67 detection increased the specificity of abnormal cervical lesions. Conclusion: P16/Ki-67 dual stain cytology in HPV-positive women performs well for diagnosis of abnormal cervical lesions and should be considered for management of HPV-positive women to avoid unnecessary colposcopy referrals.     

Identification of high-grade cervical dysplasia by the detection of p16INK4a in cell lysates obtained from cervical samples

BACKGROUND: Current cervical cancer screening approaches are based on cytology supplemented by human papillomavirus (HPV) testing in some settings. Whereas cytology is laborious and depends on the cytologists' experience, HPV testing has limited specificity when it is used to detect high-grade lesions. A dichotomous test to identify high-grade lesions with greater specificity may be a useful tool for cervical cancer screening. p16(INK4a) is a cell-cycle regulator that has demonstrated strong overexpression in cervical precancer cells and cervical cancer induced by the deregulated expression of HPV oncogenes. METHODS: The authors used a sandwich enzyme-linked immunosorbent assay (ELISA) to quantify the amount of solubilized p16(INK4a) protein in lysates that were prepared from cervical samples to detect high-grade cervical lesions. In total, 187 specimens that were obtained after sampling for conventional cytology in women who attended a cervical colposcopy clinic were analyzed. Seventy-six women underwent a biopsy, and 45 of those women showed histologically confirmed, high-grade cervical intraepithelial neoplasia. RESULTS: For 76 women with biopsy-proven diagnoses, receiver operating characteristic (ROC) analysis of different cutoff values showed an area under the ROC curve of 0.89 for the detection of high-grade cervical dysplasia. At a cutoff value of 8 U/mL, the sensitivity of the p16(INK4a) ELISA for detecting high-grade dysplastic cervical lesions was 96%. CONCLUSIONS: The data obtained in this study suggested that ELISA-based quantification of solubilized p16(INK4a) protein may have high sensitivity for detecting cervical precancer. Further population-based studies will be necessary to analyze the specificity and predictive values of p16(INK4a) protein quantification in cervical samples.     

The clinical impact of using p16INK4a immunochemistry in cervical histopathology and cytology: An update of recent developments

Cervical cancer screening test performance has been hampered by either lack of sensitivity of Pap cytology or lack of specificity of Human Papillomavirus (HPV) testing. This uncertainty can lead to unnecessary referral and treatment, which is disturbing for patients and increases costs for health care providers. The identification of p16^INK4a as a marker for neoplastic transformation of cervical squamous epithelial cells by HPVs allows the identification of HPV‐transformed cells in histopathology or cytopathology specimens. Diagnostic studies have demonstrated that the use of p16^INK4a immunohistochemistry substantially improves the reproducibility and diagnostic accuracy of histopathologic diagnoses. p16^INK4a cytology has substantially higher sensitivity for detection of cervical precancer in comparison to conventional Pap tests. Compared to HPV DNA tests, immunochemical detection of p16^INK4a‐stained cells demonstrates a significantly improved specificity with remarkably good sensitivity. About 15 years after the initial observation that p16^INK4a is overexpressed in HPV‐transformed cells we review the accumulated clinical evidence suggesting that p16^INK4a can serve as a useful biomarker in the routine diagnostic work up of patients with HPV infections and associated lesions of the female anogenital tract.     

Performance of an HPV 16/18 E6 oncoprotein test for detection of cervical precancer and cancer

HPV testing is a better alternative for cervical cancer screening, but additional procedures are required for triage of HPV positive women. HPV encoded oncoproteins E6 and E7, as the main effectors of HPV carcinogenicity represent promising triage alternatives. To evaluate performance of the test, we included 155 women from a screening study and 59 from the same referral population attending colposcopy and with precancerous lesions. All were HPV-tested with HC2 and genotyped with LiPA, and cervical swabs were tested for HPV16/18 E6 oncoproteins. Histologic specimens were reviewed and adjudicated using p16 immunohistochemistry and 55 women had confirmed histologic HSIL, 31 (56.3%) associated with HPV 16/18, 23 with other HPV types and one HPV negative. Sensitivity and specificity were estimated with histologic HSIL/cancer as gold standard. E6 oncoprotein was detectable in all but one HSIL and in all cancers where HPV16/18 DNA was detected, but in none of the cases associated with other HPV types or HPV negatives. Among the few HPV16/18 DNA positive subjects initially without HSIL (n = 4) who were E6 oncoprotein positive, precancer was detected during follow-up in 2 out of 3 with available information. Estimated sensitivity for HPV16/18-related HSIL+ was 96.8% (95%CI = 83.8–99.8) and for all HSIL+ regardless of HPV type it was 56.4% (95%CI = 43.3–68.6). Specificity was 97.5% (95%CI = 93.7–99.0). E6 oncoprotein proved as a highly sensitive and specific marker for detection of HPV16/18-related HSIL lesions in this Honduran population with limited previous screening and may be useful as a triage method in screening programs, particularly in low income countries.     

Significance of the Cytological Signs of Human Papillomavirus Infection in Anal Pap Smears of Human Immunodeficiency Virus-Infected Japanese Men Who Have Sex with Men

Purpose: The incidence of invasive anal cancer (IAC) has been increasing among human immunodeficiency virus (HIV)-positive men who have sex with men (MSM). Although cytological diagnosis is the modality of choice for screening cases of IAC, it is associated with lower sensitivity and specificity. Therefore, the present study aimed to evaluate new cytological signs of human papillomavirus (HPV) infection that may contribute to improving anal cytology. Methods: Anal cytology and HPV testing were performed using SurePath liquid-based cytology on samples obtained from 37 HIV-positive Japanese MSM. Subsequently, a histological biopsy based on high-resolution anoscopy was performed in MSM with abnormal cytological findings indicative of atypical squamous cells of undetermined significance (ASC-US) +. Also, anal Papanicolaou (Pap) smears were performed to determine cellularity, presence of dysplastic squamous cells, and other cytological signs of HPV infection. Results: Of the 37 MSM who underwent anal cytology, six tested negative for intraepithelial lesion or malignancy, three cases exhibited ASC-US, 17 exhibited low-grade squamous intraepithelial lesion (LSIL), nine exhibited high-grade squamous intraepithelial lesion (HSIL), and two remained undiagnosed. The anal Pap smears of 28 (96.6%) of the 29 MSM with abnormal cytological findings of ASC-US+ exhibited anal intraepithelial neoplasia (AIN), as revealed by histological biopsy. The median value (minimum–maximum) of the cellularity of anal Pap smears was 12 (0–70.5) nsc/hpf. In 26 MSM with LSIL and HSIL, the median dysplastic squamous cells count was 14 (2–152) dsc/smear and the cytological sign of HPV infection was 11 (2–71) hpv/smear. Of all anal Pap smears that revealed ASC-US+, 96.6% exhibited cytological signs of HPV infection. Compression-positive binucleated cells were the most prevalent among all cytological signs of HPV infection. Conclusion: For anal cytology, instead of considering a small number of dysplastic squamous cells, screening based on cytological signs of HPV infection may be beneficial for improving the diagnosis of AIN.