Differential expression of cdk inhibitors p16, p21cip1, p27kip1, and cyclin E in cervical cytological smears prepared by the ThinPrep method

Detection of cervical cancer biomarker patterns in blood plasma and urine by differential scanning calorimetry and mass spectrometry

Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN) and extent of spread of invasive carcinomas of the cervix (IC) are needed. Differential scanning calorimetry (DSC) has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms) were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS) analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate cervical cancer health.

An evaluation of the diagnostic and prognostic significance of p16(INK4a) /p21(WAF1/Cip1) immunostaining in squamous intraepithelial lesions of the uterine cervix using liquid-based cytology specimens

Human papillomavirus (HPV) infection frequently causes squamous intraepithelial lesions (SIL) of the uterine cervix and consequently gives rise to squamous cell carcinoma. It is therefore important to identify cases that potentially develop higher grades of SIL at an early stage of the disease. In this study, we thus investigated whether immunocytochemistry for p21(WAF1/Cip1) and p16(INK4a) could be applicable in the diagnosis and the prognostic prediction of SIL in combination with genomic analyses of HPV. The genomic analysis of high-risk HPV (hrHPV), which was done by reversed dot blotting and by in situ hybridization, and immunocytochemistry were performed on liquid-based cytological specimens. A cross-sectional study comprising 145 cases of NILM, ASC-US, LSIL, and HSIL indicated that the incidence of the positive cases for p16(INK4a) and p21(WAF1/Cip1) and hrHPV increased with the grade of SIL. A double positive status for p16(INK4a) and p21(WAF1/Cip1) was a significant discriminator between HSIL and LSIL/NILM, even when applied in conjunction with the genomic test for hrHPV (P = 0.006 by logistic regression analysis). However, a prospective study employing 61 NILM/ASC-US cases, revealed that the p16(INK4a) /p21(WAF1/Cip1) immunostaining was not a significant predictor for the progression of SIL, whereas the cytological diagnosis (NILM vs. ASC-US) and the infection status of hrHPV conferred significant effects on the prognosis. Immunostaining of p16(INK4a) and p21(WAF1/Cip1) provides additional information on the cytological diagnosis of SIL. A further analysis using a larger population is warranted to obtain a conclusive result regarding the prognostic significance of p16(INK4a) /p21(WAF1/Cip1) immunocytochemistry in the diagnosis of SIL.

5,8-Dimethoxy-2-Nonylamino-Naphthalene-1,4-Dione Inhibits Vascular Smooth Muscle Cell Proliferation by Blocking Autophosphorylation of PDGF-Receptor β

As the abnormal proliferation of vascular smooth muscle cells (VSMCs) plays a critical role in the development of atherosclerosis and vascular restenosis, a candidate drug with antiproliferative properties is needed. We investigated the antiproliferative action and underlying mechanism of a newly synthesized naphthoquinone derivative, 5,8-dimethoxy-2-nonylamino-naphthalene-1,4-dione (2-nonylamino-DMNQ), using VSMCs treated with platelet-derived growth factor (PDGF). 2-Nonylamino-DMNQ inhibited proliferation and cell number of VSMCs induced by PDGF, but not epidermal growth factor (EGF), in a concentration-dependent manner without any cytotoxicity. This derivative suppressed PDGF-induced [(3)H]-thymidine incorporation, cell cycle progression from G0/G1 to S phase, and the phosphorylation of phosphor-retinoblastoma protein (pRb) as well as the expression of cyclin E/D, cyclin-dependent kinase (CDK) 2/4, and proliferating cell nuclear antigen (PCNA). Importantly, 2-nonylamino-DMNQ inhibited the phosphorylation of PDGF receptorβ(PDGF-Rβ) enhanced by PDGF at Tyr(579), Tyr(716), Tyr(751), and Tyr(1021) residues. Subsequently, 2-nonylamino-DMNQ inhibited PDGF-induced phosphorylation of STAT3, ERK1/2, Akt, and PLCγ1. Therefore, our results indicate that 2-nonylamino-DMNQ inhibits PDGF-induced VSMC proliferation by blocking PDGF-Rβ autophosphorylation, and subsequently PDGF-Rβ-mediated downstream signaling pathways.

p16(INK4a) immunostaining in cytological and histological specimens from the uterine cervix: a systematic review and meta-analysis

BACKGROUND

P16(INK4a) is a biomarker for transforming HPV infections that could act as an adjunct to current cytological and histological assessment of cervical smears and biopsies, allowing the identification of those women with ambiguous results that require referral to colposcopy and potentially treatment.

MATERIAL AND METHODS

We conducted a systematic review of all studies that evaluated the use of p16(INK4a) in cytological or histological specimens from the uterine cervix. We also estimated the mean proportion of samples that were positive for p16(INK4a) in cytology and histology, stratified by the grade of the lesion.

RESULTS

Sixty-one studies were included. The proportion of cervical smears overexpressing p16(INK4a) increased with the severity of cytological abnormality. Among normal smears, only 12% (95% CI: 7-17%) were positive for the biomarker compared to 45% of ASCUS and LSIL (95% CI: 35-54% and 37-57%, respectively) and 89% of HSIL smears (95% CI: 84-95%). Similarly, in histology only 2% of normal biopsies (95% CI: 0.4-30%) and 38% of CIN1 (95% CI: 23-53%) showed diffuse staining for p16(INK4a) compared to 68% of CIN2 (95% CI: 44-92%) and 82% of CIN3 (95% CI: 72-92%).

CONCLUSION

Although there is good evidence that p16(INK4a) immunostaining correlates with the severity of cytological/histological abnormalities, the reproducibility is limited due to insufficiently standardized interpretation of the immunostaining. Therefore, a consensus needs to be reached regarding the evaluation of p16(INK4a) staining and the biomarker needs to be assessed in various clinical settings addressing specific clinical questions.

Biomarker (ProEx C, p16(INK4A), and MiB-1) distinction of high-grade squamous intraepithelial lesion from its mimics

Topoisomerase IIalpha and minichromosome maintenance protein 2 are proteins associated with aberrant S-phase induction. The current study evaluated the performance of these biomarkers (ProEx C; TriPath Oncology, Burlington, NC) compared with p16(INK4A) and MiB-1 in distinguishing high-grade squamous intraepithelial lesions (HSILs) from HSIL mimics. We collected archival cervical biopsy, cone, and curettage specimens from 96 cases in which the differential diagnosis of HSIL vs reactive epithelial changes was considered. Hematoxylin- and eosin-stained slides were reviewed independently by three pathologists and scored for the presence or absence of SIL. Immunostains for ProEx C, p16, and MiB-1 were available for 95, 96, and 59 samples, respectively, and classified blinded to histological interpretation. Strong nuclear and cytoplasmic staining for p16 and staining for MiB-1 and ProEx C that extended beyond the lower one-third of the epithelium were scored as positive. Chi(2)-tests and receiver operating characteristic analysis were conducted to statistically compare biomarker immunostaining performance against majority histological interpretation of SIL. Agreement between pathologists was also assessed by the kappa-statistic. Inter-observer agreement ranged from fair to moderate (kappa=0.37-0.57). All three biomarkers correlated strongly with the majority diagnosis of SIL (P<0.001). Positive staining for ProEx C, p16, and MiB-1 was observed in 87% (N=52/60), 84% (N=51/61), and 94% (34/36), respectively, of SIL and negative in 71% (N=25/35), 63% (N=22/35), and 52% (N=12/23), respectively, of majority diagnoses of NoSIL. The combination of p16/ProEx C predicted more SIL (92%, N=33/36) and NoSIL (61%, N=14/23) than p16 plus MiB-1 (94%, N=34/36 and 43%, N=10/23), although this difference was not statistically significant. ProEx C appears to provide an equivalent level of sensitivity and a higher level of specificity for HSIL alone or in conjunction with p16. Its principal value may be in providing a lower false positive rate for NoSIL relative to MiB-1.

p16(INK4a) Expression does not predict the outcome of cervical intraepithelial neoplasia grade 2

Spontaneous regression of cervical intraepithelial neoplasia grade 2 (CIN2) lesions has been recognized since 1955, but predictors of this are poorly understood. Among the predictive markers studied, p16(INK4a) has been suggested to be of some value in monitoring the diagnosis of CIN2. In this clinical trial, 90 Brazilian women, diagnosed to CIN2 and high-risk human papillomavirus infection, were randomized into two groups of equal size: 45 women whose lesions were excised and 45 women subjected to prospective follow-up at 3-month intervals at least for 1 year (mean 6.8 months). p16(INK4a) expression was analyzed in paraffin-embedded sections using immunohistochemical staining. Among the 45 women in the follow-up group, 42% experienced spontaneous regression, 11% showed persistence, 22% progressed to CIN3, and 20% had partial regression to CIN1 or ASCUS (atypical squamous cell undetermined signifiance). p16(INK4a) expression was detected in 68.9% of the patients. In univariate survival (Cox) analysis, no significant difference in regression was obtained between p16(INK4a)-negative and -positive CIN2 lesions (adjusted HR = 1.1; 95% CI 0.6-2.0). In conclusion, p16(INK4a) expression could be useful in the diagnosis of CIN2. However, it failed to predict the outcome of CIN2. Because of its high spontaneous regression rate, follow-up could be considered as a management option of CIN2 in young and compliant women.

Human papillomavirus testing and molecular markers of cervical dysplasia and carcinoma

Cervical cancer is the second most common cancer in women worldwide. Human papillomavirus (HPV) is the etiologic agent for the vast majority of premalignant and malignant lesions, and high-risk HPV types can be detected in almost all cases of cervical dysplasia and carcinoma. HPV testing has been widely adopted for the triage of patients after a cervical cytology screening test (Papanicolaou smear or liquid-based cervical cytology such as ThinPrep or SurePath) interpretation of atypical squamous cells of undetermined significance (ASCUS), and HPV testing is increasingly used for screening in conjunction with cervical cytology. Although cervical cytology is a highly effective screening test for cancer, it has limited specificity for clinically significant lesions in cases with low-grade cytologic abnormalities. Up to a quarter of all patients may have a false-negative result on the basis of cervical cytology testing alone. This review focuses on HPV testing methods and molecular markers and their clinical relevance. HPV testing and surrogate molecular markers of HPV infection (p16INK4a) may help identify cases that are associated with underlying high-grade premalignant or malignant lesions and may also reduce aggressive treatment of patients with low-grade lesions.

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.