Expression of p16(INK4a) in relation to histopathology and viral load of 'high-risk' HPV types in cervical neoplastic lesions

A total of 91 cervical archival biopsy series were analysed for the presence and viral load of 'high-risk' types of human papillomavirus (HR-HPV), and p16(INK4a) expression. The women had various degrees of CIN (cervical intraepithelial neoplasia). HPV 16 was the most prevalent type found, at 47% frequency. The frequency of HPV 16 increased with increasing immunoreactivity to p16(INK4a), from 39% to 44% at cases scored low to medium, to 65% at high reactivity. Thirty (33%) of the samples had negative p16(INK4a) analysis results, but were positive for HR-HPV. There was no significant correlation between viral load and the level of p16(INK4a) expression, while the grade of CIN correlated to such expressions. Thus, p16(INK4a) expression analysis yielded information which is consistent with results from the histopathology and might complement the HPV analysis in a clinical prognostic procedure in order to find women at risk for cervical cancer.     

Comparison of p16INK4a Immunocytochemistry with the HPV Polymerase Chain Reaction in Predicting High Grade Cervical Squamous Intraepithelial Lesions

Aim: To compare p16INK4a immunocytochemistry with the HPV polymerase chain reaction in predictinghigh grade cervical squamous intraepithelial lesions. Materials and Methods: This diagnostic case-control studywas conducted from January 2010 until December 2010. We obtained 30 samples, classified according to thedegree of cervical intraepithelial neoplasia (CIN): 11 samples for CIN 1, 9 samples for CIN 2, and 10 samples forCIN 3. HPV PCR, p16INK4a immunocytochemistry, and histopathological examination were performed on allsamples. Statistical analysis was conducted using SPSS 20.0. Results: In predicting CIN 2-3, we found p16INK4ato have similar specificity and positive predictive value as HPV PCR (95%, 97.2% vs 96.7%), but better sensitivity(87.5% vs 72.5%) and negative predictive value (82.1% vs 67.6%). The most prevalent types of high-risk HPVin our study were HPV 33, 35, 58, 52, and 16. Conclusions: p16INK4a has better diagnostic values than HPVPCR and may be incorporated in the triage of ASCUS and LSIL to replace HPV PCR. Genotype distribution ofHPV differs in each region, providing a challenge to develop HPV vaccines based on the epidemiology of HPVin that particular region.     

Immunohistochemical evaluation of heat shock proteins in normal and preinvasive lesions of the cervix

Heat Shock Proteins (HSPs) are molecular chaperons with multiple functions relating to cellular homeostasis. Primary, HSPs are expressed in response to cellular stresses that may also include carcinogenesis. Patterns of expression have not been extensively evaluated in the multi-step carcinogenesis of cervical cancer (Normal --> HPV infection --> Cervical Precancer --> Cancer). We evaluated the expression of HSP40, HSP60, HSP70, and HSP90 in normal tissues (N=30), in cervical intraepithelial neoplasia grade 1 (CIN1)(synonymous with productive HPV infections) (N=32), and in CIN3 (cervical precancer)(N=25) by immunohistochemistry staining (graded 0-3) and compared the results to p16INK4a, a biomarker of oncogenic HPV infections and CIN3. We found strong patterns of increased HSP40, HSP60, and HSP70 immunostaining with increasing severity of the lesion in a manner similar to p16INK4a (P(Trend)<0.0005). No difference in staining intensity by grade of lesion was observed for HSP90 (P(Trend)=0.8). Tissue patterns in CIN3 of diffuse immunostaining for HSP40 and HSP70 were analogous to those observed for p16INK4a; HSP60 immunostaining appeared more punctate within cells than for other antigens although similar tissue patterns were observed. We conclude that HSP40, HSP60, and HSP70 expressions are up-regulated in response to the development of CIN3 akin to p16INK4a expression.     

Evaluation of p16INK4a expression in ThinPrep cervical specimens with the CINtec p16INK4a assay: correlation with biopsy follow-up results

BACKGROUND: The aim of this study was to examine p16(INK4a) protein expression in ThinPrep (Cytyc Corporation, Marlborough, Mass) cervical specimens by using the CINtec p16(INK4a) Cytology Kit (Dako, Glostrup, Denmark). The ability of this assay to accurately identify underlying high-grade lesions was assessed by using follow-up biopsies and comparing these results with Hybrid Capture 2 (Digene, Gaithersburg, Md) high-risk HPV (hc(2)) results. METHODS: Three hundred ninety-eight residual ThinPrep samples were collected, and histological follow-up data were retrieved for abnormal cytology specimens. After preparation of a Papanicolaou-stained slide, a second slide was processed in preparation for p16(INK4a) immunostaining. High-risk human papillomavirus testing (hc(2)) was also performed. RESULTS: Of the 163 cytologically abnormal samples, 6-month biopsy follow-up data were available for 45% of the specimens. At initial blinded evaluation, 21 of the 26 cases with cervical intraepithelial neoplasia (CIN) II/III follow-up were positive for p16(INK4a), yielding an overall diagnostic sensitivity of 81%; 29 of the 47 cases diagnosed as CIN I or less were p16(INK4a) negative, yielding a diagnostic specificity of 62%. In comparison, the hc(2) test results indicated a diagnostic sensitivity of 100% with a diagnostic specificity of 15%. After review of selected cases with CIN II/III follow-up, 25 of 26 slides were deemed to be positive for p16(INK4a), increasing the diagnostic sensitivity to 96%. CONCLUSIONS: The CINtec p16(INK4a) Cytology Kit, in combination with ThinPrep cervical samples, allowed clear evaluation of p16(INK4a) protein overexpression. Diagnostic specificity of the CINtec p16(INK4a) assay was significantly improved relative to hc(2). To increase p16(INK4a) immunostaining in abnormal cells, a modified kit version with improved staining performance has been developed and is currently being evaluated.     

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 immunohistochemical staining and predictive value for progression of cervical intraepithelial neoplasia grade 1: A prospective study in China

p16^INK4A is strongly expressed in tissues diagnosed as cervical intraepithelial neoplasia (CIN) and cancer in women infected with human papillomavirus (HPV), but few prospective studies have evaluated p16^INK4A as a marker for the risk of low‐grade CIN (CIN1) progression. We investigated the prevalence of p16^INK4A immunostaining by CIN grade and whether overexpression of p16^INK4A in CIN1 predicts future risk for high‐grade CIN in Chinese women. 6,557 Chinese women aged 30–49 years were screened from 2003 to 2005 using cytology and carcinogenic HPV test. Colposcopy was performed on women with any abnormal result. p16^INK4A Immunostaining was performed on biopsies from all women with CIN1, as well as randomly selected women with normal or CIN grade 2 and worse (CIN2+) biopsies. Women with CIN1 were followed up without treatment. Colposcopy was performed on all untreated women at a 2‐year interval. The prevalence of p16^INK4A staining was 2.7%, 42.7%, 75.5%, 79.6% and 100% among women with normal, CIN1, 2, 3 and cancer biopsies, respectively (p < 0.001). HPV positivity was strongly associated with p16^INK4A staining [odds ratios (OR) = 12.8; 95% confidence intervals (CI): 5.2–31.6]. p16^INK4A staining of CIN1 biopsies at baseline was associated with an increased risk of finding high‐grade CIN over 2 years of follow‐up (OR = 1.43; 95% CI: 0.52–3.91). The two‐year cumulative incidence of CIN2+ for p16^INK4A positive women was higher at 10.71% than for p16^INK4A negative women at 1.30% (crude RR = 8.25, 95% CI: 1.02–66.62). p16^INK4A overexpression is strongly associated with grade of CIN and risk of progression to high‐grade CIN in women with low‐grade lesions.     

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.     

The study of the combination detection of HPV-DNA and p16INK4a in cervical lesions

The objective of this study is to detect the infection of human papillomavirus (HPV) and the expression of p16(INK4a) in cervical lesions and to investigate the interaction between hrHPV and p16(INK4a) for cervical lesions and its diagnostic efficiency. hrHPV-DNA was detected by the hybrid capture II (HC-II) system. Immunochemical method was used to detect the expression of p16(INK4a), and histopathologic test was performed to identify cervical lesions. χ(2) test and Spearman's rank correlation were used for statistical analysis. Additive effects model was used to analyze the interaction. The diagnostic sensitivity, specificity, positive predictive values, negative predictive values, accuracy, and the area under the receiver operating characteristic curve were calculated with SPSS 13.0. hrHPV and p16(INK4a) positive rate increased (P < 0.05) with histopathologic diagnosis increasing. The positive rates of hrHPV and p16(INK4a) in negative or chronic inflammation were statistically lower than that in cervical intraepithelial neoplasia (CIN)1, CIN2, CIN3, and squamous-cell carcinoma (SCC) (P < 0.05), respectively. There was a positive interaction between hrHPV and p16(INK4a), relative excess risk of interaction (RERI) was 52.49, attributable proportions of interaction (API) were 72.34%, and the synergy index (S) was 3.75. The specificity and AUC of combining hrHPV with p16(INK4a) were statistically higher than hrHPV or p16(INK4a) alone (P < 0.05). hrHPV and p16(INK4a) are useful markers for the early diagnosis of cervical lesions. A positive interaction between hrHPV and p16(INK4a) is seen. The combination of hrHPV and p16(INK4a) has a higher diagnostic accuracy than hrHPV or p16(INK4a) alone in diagnosis of cervical lesions.     

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.     

Evaluation of p16INK4a expression in ThinPrep cervical specimens with the CINtec p16INK4a assay

BACKGROUND.

The aim of this study was to examine p16^INK4a protein expression in ThinPrep (Cytyc Corporation, Marlborough, Mass) cervical specimens by using the CINtec p16^INK4a Cytology Kit (Dako, Glostrup, Denmark). The ability of this assay to accurately identify underlying high‐grade lesions was assessed by using follow‐up biopsies and comparing these results with Hybrid Capture 2 (Digene, Gaithersburg, Md) high‐risk HPV (hc₂) results.

METHODS.

Three hundred ninety‐eight residual ThinPrep samples were collected, and histological follow‐up data were retrieved for abnormal cytology specimens. After preparation of a Papanicolaou‐stained slide, a second slide was processed in preparation for p16^INK4a immunostaining. High‐risk human papillomavirus testing (hc₂) was also performed.

RESULTS.

Of the 163 cytologically abnormal samples, 6‐month biopsy follow‐up data were available for 45% of the specimens. At initial blinded evaluation, 21 of the 26 cases with cervical intraepithelial neoplasia (CIN) II/III follow‐up were positive for p16^INK4a, yielding an overall diagnostic sensitivity of 81%; 29 of the 47 cases diagnosed as CIN I or less were p16^INK4a negative, yielding a diagnostic specificity of 62%. In comparison, the hc₂ test results indicated a diagnostic sensitivity of 100% with a diagnostic specificity of 15%. After review of selected cases with CIN II/III follow‐up, 25 of 26 slides were deemed to be positive for p16^INK4a, increasing the diagnostic sensitivity to 96%.

CONCLUSIONS.

The CINtec p16^INK4a Cytology Kit, in combination with ThinPrep cervical samples, allowed clear evaluation of p16^INK4a protein overexpression. Diagnostic specificity of the CINtec p16^INK4a assay was significantly improved relative to hc₂. To increase p16^INK4a immunostaining in abnormal cells, a modified kit version with improved staining performance has been developed and is currently being evaluated. Cancer (Cancer Cytopathol) 2007. © 2007 American Cancer Society.     

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.     

Triage options to manage high-risk human papillomavirus-positive women: A population-based cross-sectional study from rural China

Improvement in managing HPV-positive women is urgently needed. Based on a population-based study which included 2112 women aged 49 to 69 from Shanxi, China, we aimed to evaluate the clinical performance of multiple triage strategies based on liquid-based cytology (LBC), p16^INK4a, viral load and partial genotyping, as a single or combined strategy for detecting cervical intraepithelial neoplasia grade 2/3 or higher (CIN2+/CIN3+) in women who tested positive by Hybrid Capture 2 (HC2). Among 452 HC2-positive women, the test positivity of LBC (ASC-US+), p16^INK4a, HPV16/18 and HPV16/18/31/33/45 were 39.6%, 38.5%, 18.0% and 40.0%, respectively. Compared to LBC (ASC-US+) triage, a single triage strategies using p16^INK4a or extended genotyping (SureX HPV16/18/31/33/45) achieved comparable sensitivity (relative sensitivity: 1.08, 95% confidence interval [CI]: 0.93-1.26 and 0.96, 95% CI: 0.76-1.22) and specificity (relative specificity: 1.05, 95% CI: 0.96-1.14 and 1.02, 95% CI: 0.92-1.14) for CIN3+. Viral load triage using a ≥50 RLU/CO cut-point also yielded similar results with LBC (ASC-US+). Among combined triage strategies, HPV16/18 genotyping with reflex p16^INK4a showed higher sensitivity and slightly lower specificity than LBC (ASC-US+) for CIN3+ detection, however, the differences were not statistically significant. Of note, after a negative result by p16^INK4a or LBC among HPV16/18 negative women, the posttest probability of CIN3+ was lower than 1%. Our study suggested that p16^INK4a, extended genotyping and increased viral load cut-point could be promising alternatives to cytology triage. Combined triage algorithms of HPV16/18 with reflex p16^INK4a or cytology, if negative, are associated with the substantial low posttest risk sufficient to release women to next screening round.     

The Association of Molecular Biomarkers in the Diagnosis of Cervical Pre-Cancer and Cancer and Risk Factors in Senegalese

Background: Cervical intraepithelial neoplasia (CIN) grading is subjective and affected by substantial rates of discordance among pathologists. Although recent studies have suggested that p16INK4a may be a useful surrogate biomarker of cervical neoplasia, Ki-67 and human papillomavirus testing have also been shown to be useful in detecting neoplasia. The purpose of this study was to determine the expression of p16INK4a and Ki-67 in cervical neoplasia and its correlations with cofactors. Methods: The study involved 69 patients with and without cervical neoplasia who underwent colposcopic directed biopsy. On each patient, two samples were taken; the first was used for immunohistochemistry and the second for molecular testing, using HPV16and18 genotyping Real-Time PCR Kit. Results: The study revealed the expression level of p16INK4a and Ki-67 in a descending order, from invasive squamous cell carcinoma (SCC), CIN2/3, CIN1 and non-dysplastic lesions. Correlations showed an association between the staining of p16NK4a and Ki-67 with the increase of age (OR: 1.79 (95%IC: 0.49 – 6.55), p = 0.037) and marital status (OR: 0.17 (95%IC: 0.04 – 0.68), p = 0.003). We found that the expressions of p16INK4a and Ki-67 were significantly different between invasive SCC vs non-dysplasia (OR: 44.57 (95%IC: 4.91 – 403.91), p <0.0001). The study showed significant correlation between HPV 16and18 infection with p16 INK4a and Ki-67 expression (OR: 0.13 (95%IC: 0.03 – 0.52), p <0.0001). Strong expression of p16INK4a and Ki-67 were observed in invasive squamous cell carcinoma, moderate staining was found in CIN2/3, weak staining in CIN1 and normal histology. Conclusion: Our findings indicate that p16INK4a and Ki-67 expressions associated strongly with cervical pathology. Therefore, p16/Ki-67 could be considered as a suitable biomarker for cervical cancer screening, particularly in HPV-based screening programs.     

Combined use of cytology,p16 immunostaining and genotyping for triage of women positive for high-risk human papillomavirus at primary screening

Human papillomavirus (HPV) testing is very sensitive for primary cervical screening but has low specificity. Triage tests that improve specificity but maintain high sensitivity are needed. Women enrolled in the experimental arm of Phase 2 of the New Technologies for Cervical Cancer randomized controlled cervical screening trial were tested for high-risk HPV (hrHPV) and referred to colposcopy if positive. hrHPV-positive women also had HPV genotyping (by polymerase chain reaction with GP5+/GP6+ primers and reverse line blotting), immunostaining for p16 overexpression and cytology. We computed sensitivity, specificity and positive predictive value (PPV) for different combinations of tests and determined potential hierarchical ordering of triage tests. A number of 1,091 HPV-positive women had valid tests for cytology, p16 and genotyping. Ninety-two of them had cervical intraepithelial neoplasia grade 2+ (CIN2+) histology and 40 of them had CIN grade 3+ (CIN3+) histology. The PPV for CIN2+ was >10% in hrHPV-positive women with positive high-grade squamous intraepithelial lesion (61.3%), positive low-grade squamous intraepithelial lesion (LSIL+) (18.3%) and positive atypical squamous cells of undetermined significance (14.8%) cytology, p16 positive (16.7%) and, hierarchically, for infections by HPV33, 16, 35, 59, 31 and 52 (in decreasing order). Referral of women positive for either p16 or LSIL+ cytology had 97.8% sensitivity for CIN2+ and women negative for both of these had a 3-year CIN3+ risk of 0.2%. Similar results were seen for women being either p16 or HPV16/33 positive. hrHPV-positive women who were negative for p16 and cytology (LSIL threshold) had a very low CIN3+ rate in the following 3 years. Recalling them after that interval and referring those positive for either test to immediate colposcopy seem to be an efficient triage strategy. The same applies to p16 and HPV16.     

p16INK4a immunohistochemistry is a promising biomarker to predict the outcome of low grade cervical intraepithelial neoplasia: comparison study with HPV genotyping

Objective

In cervical intraepithelial neoplasia (CIN), p16^INK4a immunohistochemistry has been reported to be a useful diagnostic biomarker. However, limited information is available about the association between the p16^INK4a immunohistochemistry and the outcomes of CIN. Here, we report p16^INK4a immunohistochemistry as an effective biomarker to predict the outcomes of CIN.

Methods

p16^INK4a immunohistochemistry was performed in patients with CIN from January 2000 to August 2009. Among these patients, we have performed a retrospective analysis of the medical records to evaluate the outcome of CIN 1-2 and performed statistical analysis to determine the correlation between p16^INK4a expression and the outcomes. We also performed HPV genotyping and analyzed the relation between the infecting human papillomavirus (HPV) genotype and the outcomes.

Results

A total of 244 patients, including 82 with CIN 1, 60 with CIN 2, and 102 with CIN 3, were examined. The rate of p16^INK4a overexpression increased with increasing CIN grade, 20.7% for CIN 1, 80.0% for CIN 2, and 89.2% for CIN 3, with significant differences between CIN 1 and CIN 2-3 group. In the 131 CIN 1-2 patients, the progression rate was significantly higher for the patients showing p16^INK4a overexpression than for those not showing p16^INK4a overexpression (p=0.005); the regression rate was also found to be significantly lower for the patients showing p16^INK4a overexpression (p=0.003). High-risk HPV genotypes were detected in 73 patients (73.7%). Both progression and regression rates were not significantly different between the high-risk HPV-positive and HPV-negative groups (p=0.401 and p=0.381, respectively).

Conclusion

p16^INK4a overexpression was correlated with the outcome of CIN 1-2, and p16^INK4a is considered to be a superior biomarker for predicting the outcome of CIN 1-2 compared with HPV genotyping.     

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。     

p16INK4a Immunoprofiles of Squamous Lesions of the Uterine Cervix–Implications for the Reclassification of Atypical Immature Squamous Metaplasia

p16^INK4a immunoprofiles of non-precancerous and dysplastic squamous cervical lesions were defined and applied to the reclassification of atypical immature squamous metaplasia (AIM). The immunoexpression of cytokeratin 17 (CK 17) in AIM was also evaluated. Totally, 295 cervical cone biopsies representing squamous metaplasia, reactive changes, koilocytosis, flat condyloma, CIN I, CIN II, CIN III and AIM were subjected to p16^INK4a immunohistochemistry. AIM cases were analyzed using CK 17 antibody. Typical p16^INK4a immunoprofiles for the metaplastic, LSIL/HPV and HSIL phenotypes were recorded and used for the categorization of AIM into particular phenotype groups. Results were correlated with CK 17 immunoexpression. All CIN II and CIN III lesions, all but one case of CIN I and all flat condylomas overexpressed p16^INK4a. Other non-precancerous lesions, including koilocytosis, were predominantly negative. Contrary to the sporadic and focal immunostaining, diffuse positivity was associated with the dysplastic features of the lesion. CIN II and CIN III were characterized by a diffuse, strong/weak, full-thickness staining, whereas CIN I showed a heterogeneous diffuse/focal, weak/strong, lower half positivity. One third of AIM lesions may be reclassified as HSIL, one third as LSIL/HPV and one third shows metaplastic phenotype. All AIM cases with metaplastic and LSIL/HPV phenotypes expressed CK 17 diffusely, whereas focal positivity slightly prevailed in AIM with HSIL phenotype. We conclude that p16^INK4a immunohistochemistry is a supporting method for the differential diagnosis of cervical lesions, which may be especially useful for the reclassification of AIM. The efficacy of CK 17 immunohistochemistry seems to be controversial for these purposes.     

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.     

Prognostic value of p16‐INK4A protein in women with negative or CIN1 histology result: A follow‐up study

P16‐INK4A overexpression has been proposed as a prognostic marker to manage the follow up of women with positive cytology and/or HPV test but without high‐grade cervical intraepithelial neoplasia (CIN2+). This study measures the relative risk (RR) of CIN2+ of p16 positive versus negative in these women. All the women referred to colposcopy from October 2008 to September 2010 with negative or CIN1 colposcopy‐guided biopsy were included in the study; women surgically treated or having a CIN2–3 were excluded. All baseline biopsies were dyed with hematoxylin and eosin and p16. Women were followed up according to screening protocols, with cytology or colposcopy at 6 or 12 months. CIN2/3 RRs and 95% confidence intervals (95%CI) were computed. Of 442 eligible women, 369 (83.5%) had at least one follow‐up episode. At baseline, 113 (30.6%) were CIN1, 248 (67.2%) negative, and 8 (2.2%) inadequate histology; 293 (79.4%) were p16‐negative, 64 (17.3%) p16 positive and 12 (3.2%) not valid. During follow up, we found ten CIN2 and three CIN3; of these, six were p16 positive (sensitivity 46%, 95% CI 19–75). The absolute risk among p16 positives was 9.4/100 compared to 1.7/100 of the p16 negatives (RR 5.5; 95% CI 1.7–17.4). The risk was also higher for CIN1 than for histologically negative women (RR 4.4; 95% CI 1.3–14.3). The RR for p16 in CIN1 did not change (RR 5.2; 95% CI 0.6–47.5). P16 overexpression is a good candidate for modulating follow‐up intensity after a negative colposcopy but is limited by its low prospective sensitivity.