Surrogate endpoint biomarkers and their modulation in cervical chemoprevention trials

Quantitation of spatial and temporal variability of biomarkers for Barrett's Esophagus

Chemoprevention and risk-stratification studies in Barrett's esophagus (BE) rely on biomarkers but the variability in their temporal and spatial expression is unknown. If such variability exists, it will impact sampling techniques and sample size calculations. Specimens from three levels of biopsies over two serial endoscopies in nondysplastic BE patients were analyzed for aneuploidy, proliferation markers (Ki67, Mcm2), and cell cycle markers (cyclin A and cyclin D1). A modification of the image cytometry technique, where cytokeratin staining automatically distinguished epithelial and stromal cells, measured aneuploidy on whole tissue sections. Other biomarkers were studied by immunohistochemistry. Coefficient of variability (SD/mean) was calculated; a value <10% indicated low variability. A total of 120 specimens (20 subjects each with three biopsy levels at two time points) from nondysplastic BE patients (71 ± 8.8 years, all Caucasian, 90% males, C5.1M7.5 ± 3.4 cm) were analyzed. The mean interval between endoscopies was 32.8 ± 8.4 months. Aneuploidy had a spatial variability of 6.8% at visit 1 (mean diploid index: 1.1 ± 0.09) and 7.9% at visit 2 (mean diploid index: 1.1 ± 0.06) and a temporal variability of 7.0-8.1% for the three levels. For other biomarkers, the spatial variability ranged from ∼5 to 30% at visit 1 and 11-92% at visit 2 and the temporal variability ranged from 0 to 77%. To conclude, of all the biomarkers, only aneuploidy had both spatial and temporal variability of <10%. Spatial and temporal variability were biomarker dependent and could be as high as 90% even without progression. These data will be useful to design chemoprevention and risk-stratification studies in BE.

Detection of HPV E7 oncoviral protein in cervical lesions by a new antibody

The availability of a new E7 mAb-based immunohistochemistry (IHC) detection assay, Cervimax, allowed for the first time reliable testing of the E7 protein marker in formalin-fixed and paraffin-embedded tissues from cervical lesions. E7-specific IHC staining patterns were compared with those patterns of cervical cancer biomarkers, including the viral capsid protein L1 and the surrogate biomarkers p16INK4A, p53, hTERT, ubiquitin, and Ki67. The use of a tissue microarray of 138 cervical tissue cores from different pathologic stages allowed for a first profiling of the various markers in comparison with E7. Cervimax staining patterns closely overlap with those from p16INK4A and human telomerase reverse transcriptase (hTERT) in IHC staining for high-grade cervical intraepithelial neoplasia and squamous cell carcinoma. In squamous cell carcinoma, E7 immunostaining matched better to hTERT and ubiquitin profiles. On the contrary, the pattern of E7 and L1 were different in all the squamous lesions. The nuclear staining of E7 significantly discriminates between low-grade cervical intraepithelial neoplasia and high-grade cervical intraepithelial neoplasia in the basal, parabasal, and superficial layers. The results obtained in the presented pilot study suggest E7 as a valid candidate biomarker for all the stages of the malignant progression of cervical cancer; however, more extensive studies are needed to confirm the causal effect of the oncoprotein E7 in the diagnosis of human papillomavirus-induced diseases. These results also suggest that the diagnostic interpretation of cervical lesions could be increased by the combination of E7 and L1 staining in the evaluation of risk of progression, because related to different phases of viral integration.

Effects of HPV-16 E5, E6 and E7 proteins on survival, adhesion, migration and invasion of trophoblastic cells

Among high-risk human papillomaviruses (HPV), HPV-16 infection is the most prevalent causative factor for cervical cancer. Beside other mucosal targets, HPV-16 was reported to infect the placenta and to replicate in trophoblastic cells. Since these cells share invasive properties of tumoral cells, they represent an ideal model to investigate several oncogenic processes. In the present work, we analyzed the impacts of HPV-16 E5, E6 and E7 oncoproteins on the trophoblastic model. Our results showed that E5 impaired the viability of trophoblastic and cervical cell lines but E6 and E7, favoring cell growth, neutralized the E5 cytotoxic effect. In addition, E5 decreased the adhesiveness of trophoblastic cells to the tissue culture plastic and to endometrial cells similarly as described previously for E6 and E7. E5 and E6 plus E7 increased also their migration and their invasive properties. Cells expressing HPV-16 early proteins under the control of the long control region endogenous promoter displayed growth advantage and were also more motile and invasive compared with control cells. Interestingly, the E-cadherin was downregulated in trophoblastic cells expressing E5, E6 and E7. Nuclear factor-kappaB and activator protein-1 activities were also enhanced. In conclusion, HPV-16 early proteins enhanced trophoblastic growth and intensify the malignant phenotype by impairing cell adhesion leading to increased cellular motile and invasive properties. HPV-16 E5 participated, with E6 and E7, in these changes by impairing E-cadherin expression, a hallmark of malignant progression.

p16 and MIB1 improve the sensitivity and specificity of the diagnosis of high grade squamous intraepithelial lesions: methodological issues in a report of 447 biopsies with consensus diagnosis and HPV HCII testing

OBJECTIVE

Many investigators are studying the additional value of biomarkers to improve histopathologic agreement, but few are using the same methodologies. Our objectives in this analysis to differentiate High-grade Squamous Intraepithelial lesions (HGSIL) from Low Grade Squamous Intraepithelial Lesions (LGSIL), atypia, and normal were: (1) to examine the rate of Human Papilloma Virus High-Risk positivity (HPV HR+), (2) to compare and grade the basal, parabasal, intermediate, and superficial layer staining of each marker, (3) to determine the optimal qualitative threshold for markers, (4) to compare p16 and MIB1 agreement, and (5) to examine the sensitivities and specificities using each markers alone and together.

METHODS

A sample of biopsies from 208 patients were chosen from a total of 1850 patients and 3735 biopsies obtained during the course of ongoing optical trials. At least two independent blinded reviews were performed for each biopsy. A third review was performed if there was a disagreement between the two reviews. Both endocervical and ectocervical samples were stained for p16 and MIB1. A grading system that is delineated in the text ranged from 0 to 3 for both markers and each biopsy was scored by each cell layer. Frequencies, sensitivities, and specificities were calculated using Statistica. An ANOVA was used to compare p16 and MIB1 staining in the epithelial layers. Finally the sensitivity and specificity of each marker alone and together were examined.

RESULTS

453 specimens from 208 patients whose final diagnoses were normal (n=244), low-grade (LG) (n=59), and high-grade (HG) (n=144) were selected for analysis. 447 of 453 specimens were available for staining. Most LG and HG lesions were HPV HR positive. Endocervical samples stained positive less often than ectocervix and often results were discordant from ectocervical results. The analysis by layers showed pronounced increases in staining of both p16 and MIB1 as lesions progressed from normal to LG to HG. The cutoff or threshold for p16 was 0 versus 1-3 while for MIB1 it was 0-1 versus 2-3. Using the intermediate epithelial layer measurement of both p16 and MIB1 in HPV High-Risk Positive separated the normal tissue from LGSIL, normal from HGSIL, and LGSIL from HGSIL by a statistically significant margin (p<0.05). Each marker had sensitivities and specificities for the diagnosis of HGSIL versus LGSIL and normal of approximately 85-90% and this improved by 5% for both sensitivity and specificity when used together (p16 sensitivity 90%, specificity 85%; MIB1 sensitivity 89%, specificity 87%; together sensitivity 94%, specificity 90%).

CONCLUSION

Several important methodological issues have been studied. Overall, p16 and MIB1 are promising markers to help pathologists differentiate HG lesions from all else. The staining of the endocervix and the ectocervix do not always agree, and the ectocervix more often stains positive with the presence of HGSIL. Each marker is helpful and both are helpful together. In conclusion, both markers are useful for the confirmation of HG lesions.

Vasoactive intestinal peptide enhances wound healing and proliferation of human bronchial epithelial cells

In the present study, we investigated the effects of vasoactive intestinal peptide (VIP) on wound healing of bronchial epithelium. Wound healing of the mechanical damaged human bronchial epithelial cells (HBEC) was observed in the absence or presence of VIP. Effects of VIP on chemotactic migration, cell proliferation of HBEC were also tested. HBEC chemotaxis was assessed by the blind well chamber technique, the cell cycle was determined by flow cytometry, and cell proliferation was determined by measuring the expression of proliferating cell nuclear antigen Ki67. Effects of VIP on epithelial E-cadherins protein and mRNA were also measured by immunohistochemistry and RT-PCR. The results showed that VIP accelerated the recovery of wound area of HBEC. VIP increased the migration and proliferation of HBEC, and these effects were blocked by a VPAC1 receptor antagonist. VIP also increased the expression of E-cadherin mRNA and protein in HBEC, suggesting that protective effects of VIP on wound healing may be related to its ability to increase the expression of E-cadherin. In conclusion, VIP has protective effects against human bronchial epithelial cell damage, and the beneficial effects of VIP might be mediated, at least in part, by VPAC1, and associated with increased expression of E-cadherin.

Up-regulation of proliferating cell nuclear antigen (PCNA) is closely associated with high-risk human papillomavirus (HPV) and progression of cervical intraepithelial neoplasia (CIN), but does not predict disease outcome in cervical cancer

OBJECTIVE

Proliferating cell nuclear antigen (PCNA) is essential for DNA replication of mammalian cells and their small DNA tumour viruses. The E7 oncoprotein of high-risk human papillomavirus (HPV) is known to activate PCNA, shown to be up-regulated in CIN and cervical cancer (CC), but still incompletely studied as an intermediate endpoint marker in this disease.

MATERIAL AND METHODS

As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for PCNA, and tested for HPV using PCR with three primer sets (MY09/11, GP5+/GP6+, SPF). Follow-up data were available from all SCC patients, and 67 of the CIN lesions had been monitored with serial PCR for HPV after cone treatment.

RESULTS

Expression of PCNA increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 21.77; 95%CI 6.59-71.94) (p = 0.0001). Intense PCNA expression was 100% specific indicator of CIN, with 100% PPV, but suffers from low sensitivity (34.8%) and NPV (10.8%). PCNA expression was also significantly associated to HR-HPV with OR 3.02 (95%CI 1.71-5.34) (p = 0.0001), and this association was not confounded by the histological grade (Mantel-Haenszel common OR = 2.03; 95%CI 1.06-3.89) (p = 0.033). Expression of PCNA did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in CC in univariate or in multivariate analysis.

CONCLUSIONS

Up-regulation of PCNA was closely associated with HR-HPV and progressive CIN, most feasibly explained by the abrogation of normal cell cycle control by the E7 ongogene, reverting the p21(Cip1)-mediated inhibition of PCNA. However, the fact that PCNA is also expressed in normal squamous epithelium precludes the use of this marker as a potential screening tool for CC.

DNA ploidy compared with human papilloma virus testing (Hybrid Capture II) and conventional cervical cytology as a primary screening test for cervical high-grade lesions and cancer in 1555 patients with biopsy confirmation

BACKGROUND

Because 80% of cervical cancers arise in low-resource settings, many inexpensive strategies are being tested. In that spirit, the authors are testing large-scale genomic or DNA ploidy measurements as an inexpensive and semiautomated strategy.

METHODS

Patients entered either a screening or diagnostic study of several optical technologies: quantitative cytology, quantitative histopathology, and fluorescence and reflectance spectroscopy using a point probe, a multispectral digital colposcope, or a combination of the two. We calculated sensitivities, specificities, positive and negative predictive values, and their confidence interval testing conventional cytology, Hybrid Capture (HC) II testing, and DNA ploidy measured on the Feulgen-stained quantitative Pap smear.

RESULTS

The current investigation reports on 1555 patients for whom colposcopically directed biopsies were read 3 times by study pathologists. The final histopathologic diagnosis was high grade (cervical intraepithelial neoplasia [CIN] 2, CIN 3, carcinoma in situ [CIS], and cancer) in 16% of patients. Using high-grade squamous intraepithelial lesions (SILs) histopathology as the threshold and gold standard, the sensitivity and specificity, respectively, were: 0.47 and 0.96 for conventional cytology, 0.91 and 0.80 for HC II, and 0.59 and 0.93 for DNA ploidy. The positive and negative predictive values (PPV, NPV) for conventional cytology were 0.70 and 0.90, 0.46 and 0.98 for HC II, and 0.63 and 0.92 for DNA ploidy.

CONCLUSIONS

DNA ploidy shows comparable sensitivity, specificity, PPV, and NPV values to conventional cytology and HC II. Unlike conventional cytology, DNA ploidy is semiautomated and can be performed in less than 8 hours. Cost effectiveness studies are under way, but in the authors' laboratory DNA ploidy is inexpensive.

Fluorescent nanocrystals for use in early cervical cancer detection

BACKGROUND

Quantum dots (qdots) are a promising alternative to organic fluorophores for biological imaging. Advantages of quantum dots over organic fluorophores include broad excitation coupled with narrow, tunable emission, high resistance to chemical and metabolic degradation, a higher photobleaching threshold and finally the ability to be modified with a targeting ligand. These many properties allow quantum dots to be used in conjunction with optical detection methods for imaging.

METHODS

We are investigating the use of quantum dots to detect precancerous biomarkers. We have directly targeted epidermal growth factor receptors with quantum dots conjugated to anti-EGFR antibodies.

RESULTS

Compared to appropriate controls, we do see specific labeling of EGF receptors.

CONCLUSIONS

Quantum dots provide a promising alternative to conventional organic dyes for biological imaging. Combined with optical imaging technologies, quantum dots can help visualize changes in cervical cancer at the molecular level. This ability may alert health care providers to the need for intervention before a cancer can metastasize.

Proteomic analysis of progressive factors in uterine cervical cancer

Human papillomavirus (HPV) infections play a crucial role in the progress of cervical cancer. The high-risk HPV types are frequently associated with the development of malignant lesions. Some of the latest studies have demonstrated that the high-risk HPV 16 and 18 are predominantly detected in the more aggressive cancers. In the present study, we aimed to establish the proteomic profiles and characterization of the tumor related proteins by using two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). For proteomic analysis, patients infected by HPV 16 or 18 were included in this study. We compared nuclear protein and cytoplasmic protein, separately by using the subcellular fraction. Differential protein spots between cervical cancer with high-risk HPV, HPV 16 or HPV 18, and HaCaT cell lines were characterized by 2-DE. Those proteins analyzed by peptide mass fingerprinting based on MALDI-TOF MS and database searching were the products of oncogenes or proto-oncogenes, and the others were involved in the regulation of cell cycle, for general genomic stability, telomerase activation, and cell immortalization. However, there was no difference in protein characterization for cervical cancer between HPV 16 and HPV 18 infection. Nonetheless, these data are valuable for the mass identification of differentially expressed proteins involved in human uterine cervical cancer. Moreover, the data has enormous value for establishing the human uterine cervical cancer proteome database that can be used in screening a molecular marker for the further study of human uterine cervical cancer, and also for studying any correlation among the cancers induced by HPV.

Is suicide ideation a surrogate endpoint for geriatric suicide?

The present study explored the validity of treating suicide ideation as a surrogate endpoint that can serve as a proxy for suicide in clinical intervention research with suicidal seniors. Two criteria; that suicide ideation is modulated by the proposed intervention and that modulation of suicide ideation leads to a quantitative reduction in suicide rates, were the focus of this review. A series of literature searches of the PsychINFO and Medline databases were conducted on the terms geriatric, elderly, seniors, suicide, self-destruction, clinical, randomized, trial, treatment, intervention , and ideation . Articles were analyzed if they provided sufficient information to examine whether an intervention effectively led to a reduction in suicide ideation among seniors. Two hundred and eight articles were considered for potential inclusion in this study, with 19 articles meeting final inclusion criteria. The articles reviewed were divided into three broad categories: articles supporting suicide ideation as a surrogate endpoint for geriatric suicide ( n = 6); those not supporting this hypothesis ( n = 1); and those providing insufficient information to test the hypothesis ( n = 12). The present analysis provided modest evidence for suicide ideation as a surrogate endpoint for geriatric suicide, due, in part, to a paucity of randomized controlled trials of treatment interventions for suicidal seniors, thus demonstrating a clear need for research in this area. Implications of utilizing surrogate endpoints in suicide research are discussed.

Positron Emission Tomography Imaging of Cell Proliferation in Oncology

Tumour-cell proliferation is a hallmark of the malignant phenotype. Positron emission tomography (PET) offers a unique method of imaging biological and biochemical changes in vivo. Radiolabelled thymidine and thymidine analogues are currently in development as PET tracers. By studying the uptake and kinetics of such compounds using PET, a measure of DNA synthesis and hence cell proliferation can be obtained. Molecular imaging of cellular proliferation with PET is now possible, and has the potential to play an important role in the evaluation of efficacy of new anti-cancer agents.

Cervical cancer chemoprevention, vaccines, and surrogate endpoint biomarkers

At the Second International Conference on Cervical Cancer, held April 11-14, 2002, experts in cervical cancer prevention, detection, and treatment reviewed the need for more research in chemoprevention, including prophylactic and therapeutic vaccines, immunomodulators, peptides, and surrogate endpoint biomarkers. Investigators and clinicians noted the need for more rigorous Phase I randomized clinical trials, more attention to the risk factors that can affect study results in this patient population, and validation of optical technologies that will provide valuable quantitative information in real time regarding disease regression and progression. They discussed the role of the human papillomavirus (HPV) in cervical cancer development and the importance of developing strategies to suppress HPV persistence and progression. Results in Phase I randomized clinical trials have been disappointing because few have demonstrated statistically significant regression attributable to the agent tested. Researchers recommended using a transgenic mouse model to test and validate new compounds, initiating vaccine and immunomodulator trials, and developing immunologic surrogate endpoint biomarkers.

In situ hybridization analysis of human papillomavirus DNA segregation patterns in lesions of the female genital tract

Various histologic features may be used to divide human papillomavirus (HPV)-related lesions of the genital tract into two groups: condylomata and "low-grade" or grade 1 cervical intraepithelial neoplasias (CIN 1) versus "high-grade" or grade 2 and 3 intraepithelial neoplasias. Using in situ hybridization analysis we correlated HPV DNA type with histologic features in 350 biopsies of lesions from the cervix, vulva, and perianal region. HPV DNA was most commonly found in vulvar and perianal condylomata (39/46, 85%), whereas the rate in CIN 1 lesions was 72% (86/120). The rates were 53% (40/76) and 57% (12/21) in CIN 2/3 and vulvar intraepithelial neoplasm (VIN) grades 2 and 3, respectively. The HPV type in all but 2 of the 39 perianal and vulvar condylomata which contained HPV was 6/11. Despite their similar histologic features, the HPV type in only 23 of 86 (27%) CIN 1 cases with detectable HPV was 6/11 compared to 31 of 86 (36%) which contained HPV 16-related DNA and 32 of 86 (37%) which contained HPV 31,-33, or -35-related DNA. The viral DNA in the majority of CIN 2/3 lesions and all of the VIN 2/3 lesions was HPV-16 related; no CIN 2/3 or VIN 2/3 lesion had HPV 6/11-related DNA. It is concluded that although cutaneous genital tract condylomata are highly associated with HPVs of low oncogenic potential (types 6 and 11), these HPV types are not as frequent as the oncogenic HPVs (16, 31, 33, and 35) in CIN 1 lesions. Further, HPV 6/11 appears to be very rarely associated with CIN 2/3 or VIN 2/3 lesions.