PREDICTIVE VALUE OF p53 AND pRb IMMUNOSTAINING IN LOCALLY ADVANCED BLADDER CANCER TREATED WITH CYSTECTOMY

Purpose

We elucidate the association between altered immunostaining for retinoblastoma gene protein (pRb) and p53 nuclear proteins, and cancer specific death in patients treated with cystectomy for locally advanced bladder cancer.

Materials and Methods

The hospital records of 173 patients treated with cystectomy for advanced urothelial bladder cancer between 1967 and 1992 were retrospectively reviewed. Representative biopsies obtained before treatment were sectioned and stained using the standard immunohistochemical technique with antibody DO-7 (p53) and antibody PMG3-245 (pRb). A tumor was considered to have an altered p53 expression if 20% or more of tumor cells exhibited nuclear staining. Similarly, if no tumor cell had nuclear immunostaining the tumor was considered to have an altered pRb expression.

Results

An altered expression was observed for p53 in 98 tumors (57%) and for pRb in 60 (35%). In a proportional hazards analysis no association was found between an altered expression of pRb or p53 and cancer specific death. This finding was also true in another analysis when the results of immunostaining for pRb and p53 were combined.

Conclusions

An altered expression for pRb and/or p53 was not correlated to cancer specific death. Thus, these parameters could not be used as predictors of treatment outcome after cystectomy for locally advanced bladder cancer.     

METHOTREXATE RESISTANCE IN HUMAN UROEPITHELIAL CELLS WITH p53 ALTERATIONS

Purpose

Bladder cancers are frequently treated with combination chemotherapy that includes methotrexate (MTX). The development of drug resistance is a common problem in treatment of bladder cancers. We tested if the status of p53 and/or pRb affects the development of MTX resistance in bladder epithelial cell lines.

Materials and Methods

We used two isogeneic sets of cell lines in which we manipulated the status of p53 and/or pRb by transformation with Human Papillomavirus (HPV) E6 and/or E7 or with a transdominant TP53 mutant (TP53 sup 143). One series of isogeneic origin was derived from normal human uroepithelial cells (HUC), and the other was derived from a human transitional cell carcinoma (TCC). Cell lines with p53 and/or pRb alterations were cultured for six months while increasing the MTX concentration in each line, as resistance developed.

Results

Two cell lines with both pRb and p53 alterations, alpha E6/E7-HUC and alpha E7-HUC^p53mu, acquired the greatest resistance (750 nM) to MTX. One line with p53 loss, E6-TCC#10, acquired intermediate resistance (500 nM), while two lines, alpha E7-HUC and E7-TCC#10, with altered pRb but wildtype p53, showed low levels of MTX resistance (125 nM and 80 nM, respectively). Two clear mechanisms of MTX resistance were identified. All five MTX resistant cell lines showed altered uptake of MTX. In addition, two of five MTX resistant cell lines, both with altered p53, showed dihydrofolate reductase (DHFR) amplification.

Conclusions

p53 alteration increases the risk for development of drug resistance by both DHFR amplification and altered MTX transport in transformed human bladder epithelial cell lines.     

The expression of key cell cycle markers and presence of human papillomavirus in squamous cell carcinoma of the tonsil

BACKGROUND: Chemical carcinogens induce squamous cell carcinoma (SCC) of the head and neck by targeting the p53 and the retinoblastoma (pRb) pathways. Human papillomavirus (HPV) might have an etiologic role in these cancers at particular sites. Few studies have compared cell cycle protein expression in HPV-positive and HPV-negative tumors in this region. METHODS: Fifty tonsil SCCs were analyzed for HPV by PCR and for expression of cell cycle proteins (p53, pRb, p16(INK4A), p21(CIP1/WAF1), p27(KIP1), and cyclinD1) by immunohistochemistry. RESULTS: HPV was present in 42%; almost all were type 16. There were statistical associations between HPV positivity and reduced expression of pRb and cyclinD1, overexpression of p16, and younger patient age. Tumor with down-regulated p27 tended to have down-regulated pRb and p21. CONCLUSIONS: HPV-positive tonsil SCCs have distinct molecular pathways. Their association with younger patient age suggests that they are biologically distinct from HPV-negative tumors.     

Survival outcome of tonsillar squamous cell carcinoma (TSCC) in the context of human papillomavirus (HPV): A systematic review and meta-analysis

Objective

The objective of our study was to assess whether HPV-positive TSCC had better survival and prognosis rates, when compared to HPV-negative TSCC.

Hypermethylation of the thrombospondin-1 gene is associated with poor prognosis in penile squamous cell carcinoma

OBJECTIVE

To evaluate the presence of human papillomavirus (HPV) infection, the methylation status in the promoter region of thrombospondin‐1 (TSP‐1), RAS association domain family 1A (RASSF1‐A) and p16 genes, and the expression of TSP‐1, CD31, p16 and p53 proteins in patients diagnosed with penile cancer, and the possible associations between these variables and clinical and pathological features.

PATIENTS AND METHODS

HPV types, gene promoter hypermethylation and protein expression were analysed by reverse line blot, methylation‐specific polymerase chain reaction, and immunohistochemistry, respectively, in 24 penile squamous cell carcinomas.

RESULTS

HPV infection was detected in 11 of 24 cases (46%), and TSP‐1, RASSF1‐A and p16 genes were hypermethylated in 46%, 42% and 38% of the tumours, respectively. TSP‐1 hypermethylation was associated with unfavourable histological grade (grade 3; P = 0.033), vascular invasion (P = 0.023), weak expression of TSP‐1 protein (P = 0.041), and shorter overall survival (P = 0.04). TSP‐1 expression was not associated with microvessel density. However, RASSF1‐A hypermethylation was more frequent in T1 tumours (P = 0.01), and p16 hypermethylation was not associated with any of the tested variables except for absence of p16 expression (P = 0.022).

CONCLUSION

In summary, the epigenetic inactivation of TSP‐1 and RASSF1‐A genes is associated with pathological variables and seems to be of prognostic significance in penile cancer.     

Combined p53 and retinoblastoma protein detection identifies persistent and regressive cervical high-grade squamous intraepithelial lesions

Most cervical high-grade squamous intraepithelial lesions (HSILs) persist, but approximately one third regress (ie, no HSIL in follow-up biopsies). To identify factors related to histologic proven persistence or regression. Twenty-eight small histologic (marker) biopsies with adequate follow-up were analyzed for human papillomavirus (HPV) genotypes and different immunoquantitative proliferation, cell cycle regulation, and differentiation markers. All cases had a biopsy-interval between the marker and first follow-up biopsy of at least 100 days (median, 8.2 months; range, 3.4-22.5 months). Follow-up was classified as regression or persistence. All lesions were high-risk (hr) HPV and p16 positive, 63% for HPV-16 or HPV-16 mixed with other hr genotypes, while 37% had other hrHPV types. The marker biopsies of the persistent HSILs had lower p53 and retinoblastoma protein (pRb) detected in the deep half of the epithelium (P = 0.001 and 0.02, respectively) than nonpersistent HSILs. The degree of positivity of p16, Ki-67, cyclin D1, lesion extent, positivity of the resection margins, and patient age were all unrelated to persistence or regression. Lesions with HPV-16 or mixed-16 genotypes had a significantly lower percentage of pRb (P = 0.02), p53 (P = 0.02), and cyclin D (P = 0.04) positive nuclei in the deep epithelial layers. In agreement with this, type-16 positive HSILs had a lower regression percentage than those with other HPV types, but the difference was not significant. HSILs with combined negativity/low positivity for p53 and pRb protein in small histologic biopsies are highly likely to persist, contrasting those in which one of these cell cycle regulators is strongly positive (p53 > 15%; pRb > 40%).     

Discrimination of ‘Driver’ and ‘Passenger’ HPV in Tonsillar Carcinomas by the Polymerase Chain Reaction, Chromogenic In Situ Hybridization, and p16INK4a Immunohistochemistry

Human papillomavirus (HPV) positive tonsillar squamous cell carcinoma (TSCC) is associated with a favorable clinical outcome. However, the HPV detected in a given tumor may be causal (driver HPV) or an incidental bystander (passenger HPV). There is a need to discriminate these forms of HPV in TSCCs to understand their impact on HPV as a biomarker for use in TSCC patient management. This study has compared the polymerase chain reaction (PCR), chromogenic in situ hybridization (CISH), and p16^INK4a immunohistochemistry in the assessment of HPV status in TSCC. Archival specimens of TSCC from thirty patients were investigated. HPV was detected by PCR in 25/30 (83.3%) tumors; HPV16 (70.0%) and HPV52 (6.7%) were the most common types. HPV was corroborated by CISH in 22/25 (88.0%) specimens; integrated HPV was implicated by the presence of punctate signals in each of these cases. p16^INK4a staining was found in 20/22 (90.9%) HPV PCR positive samples; two PCR/CISH HPV positive cases were p16^INK4a negative and two HPV negative samples were p16^INK4a positive. These data suggest that a minority of HPV positive TSCCs are positive for passenger HPV and that two or more assays may be required for diagnosing driver HPV status. Further studies are required to exam whether oropharyngeal tumors positive for passenger HPV have a less favorable prognosis than tumors that are driver HPV positive. The clinical significance of TSCCs that test HPV negative/p16^INK4a positive, PCR and CISH HPV positive/p16 ^INK4a negative, or PCR HPV positive/p16 ^INK4a and CISH negative, also requires further investigation.     

Giant condylomata acuminata of Buschke and Lowenstein: A peristomal variant

INTRODUCTION

Giant condylomata acuminata (GCA) is a rare, locally invasive tumour that may undergo malignant transformation. It was first described a HPV-induced penile tumour which clinically resembled both a squamous cell carcinoma and condyloma acuminatum, often arising from a pre-existing warty lesion. We describe a case of peri-stomal GCA transformation into invasive squamous cell carcinoma (SCC), which is, to our knowledge, the first report of this in the literature.

PRESENTATION OF CASE

A 74 year old gentleman developed an acuminate, papillomatous peristomal eruption around a fifty year old ileostomy, with biopsies of the eruption showing reactive changes. Two years later, he developed ulcerating plaques affecting the previously papillomatous areas and an erythematous nodular lesion involving the superior part of the ileostomy and adjacent skin. Histological examination of the ileostomy lesion showed focal small islands of atypical squamous epithelium, and moderately differentiated invasive squamous cell carcinoma was shown in the excised tissue subsequently. Human papillomavirus (HPV type 16), p16 and p53 tumour suppressors were positive in the peri-stomal skin sample.

DISCUSSION AND CONCLUSIONS

Recurring, changing papillomatous lesions in the peristomal area should be reviewed with a high index of suspicion in relation to GCA tumours as they can progress to invasive squamous cell carcinomas.Abbreviations: GCA, giant condylomata acuminata; SCC, squamous cell carcinoma; HPV, human papillomavirus; UC, ulcerative colitis     

EXPRESSION OF BCL-2 AND BCL-X IN BLADDER CANCER

Purpose

TP53 and RB1 gene mutations in bladder transitional cell carcinoma (TCC) are correlated with grade, stage, recurrence, and survival and may correlate with tumor cell apoptotic potential. Overexpression of the bcl-2 and bcl-X anti-apoptotic genes has been correlated with poor prognosis and chemotherapy resistance in other systems. Similar studies have not been performed in TCC. We thus sought to determine expression of bcl-2 and bcl-X in TCC and correlate these with stage, survival and abnormal pRb or p53 expression.

Materials and Methods

Forty-two TCC samples (19 Ta and 23 locally advanced tumors) and normal urothelial controls were examined. Immunohistochemistry for p53, pRb, bcl-2 and bcl-X was performed on an automated system using indirect streptavidin biotin/horseradish peroxidase staining. Western immunoblot analysis was performed on bladder cancer cell lines to further characterize bcl-X expression. Recurrence-free and disease-specific survival were retrospectively determined. Kaplan-Meier survival curves were compared using the log rank test, and correlation of abnormal staining with stage and p53 or pRb status was determined using Fisher's exact test.

Results

Bcl-2 was expressed in less than 1% of normal urothelial cells, but moderate expression of bcl-x was found in all normal urothelial samples. Only 7.0% of TCC samples (1/19 Ta and 2/23 locally advanced tumors) demonstrated bcl-2 overexpression. Bcl-X overexpression was observed in 45.2% of TCC (8/19 Ta and 11/23 locally advanced tumors). Western blot analysis also revealed that both the long (29 kDa) anti-apoptotic form and short (19 kDa) pro-apoptotic form were overexpressed in bladder cancer cell lines and normal human urothelial cells. Bcl-X overexpression was weakly correlated with normal p53 expression (p = 0.06). There were no correlations of bcl-2 and bcl-X overexpression with abnormal p53, pRb, or tumor stage. There were no differences in recurrence-free or overall survival in patients with abnormal bcl-X staining.

Conclusions

Bcl-2 overexpression is rare in TCC. Bcl-X overexpression is common, likely reflecting its expression pattern in normal urothelium, but is not correlated with stage or abnormal p53 or pRb staining. Within the power limitations of this small study, bcl-X overexpression is not correlated with recurrence or survival.     

Combined p53 and MDM2 biomarker analysis shows a unique pattern of expression associated with poor prognosis in patients with renal cell carcinoma undergoing radical nephrectomy

What's known on the subject? and What does the study add? Unlike most other cancers mutations of the p53 gene (TP53), typically indicated by increased p53 expression, are rare in renal cell carcinomas (RCC) and there is no evidence that mutation of TP53 is associated with outcome or treatment response. However, whilst TP53 mutations are not linked with outcome, p53 expression is as we show here. Our study is the first to demonstrate simultaneously that patients with increased p53 expression (significantly associated with MDM2 expression), have reduced disease specific survival even though the expressed p53 is rarely mutated. We therefore identify increased expression of wild‐type p53 and MDM2 in RCC as targets for future therapeutic approaches.

OBJECTIVE

• ? To resolve much debated issues surrounding p53 function, expression and mutation in renal cell carcinoma (RCC), we performed the first study to simultaneously determine p53/MDM2 expression, TP53 mutational status (in p53‐positive patients) and outcome in RCC.

PATIENTS AND METHODS

• ? In total, 90 specimens obtained from patients with RCC, who were treated by radical nephrectomy, were analyzed by immunohistochemistry for p53 and MDM2 on a tissue microarray, and p53 was functionally and genetically analyzed in p53 positive samples.
• ? Outcome analysis was by the Kaplan–Meier method and univariate analysis was used to identify variables for subsequent multivariate analysis of correlations between clinical parameters and biomarker expression.

RESULTS

• ? Up‐regulation of p53 in RCC is strongly linked with MDM2 up‐regulation (P < 0.001).
• ? Increased coexpression of p53 and MDM2 identifies those patients with a significantly reduced disease‐specific survival by univariate (P= 0.036) and Cox multiple regression analysis (P= 0.027; relative risk, 3.20).
• ? Functional (i.e. functional analysis of separated alleles in yeast) and genetic analysis of tumours with increased p53 expression shows that most patients (86%) retain wild‐type p53.

CONCLUSIONS

• ? Coexpression of p53/MDM2 identifies a subset of patients with poor prognosis, despite all of them having organ‐confined disease.
• ? Up‐regulated p53 is typically wild‐type and thus provides a mechanistic explanation for the association between p53 and MDM2 expression: up‐regulated wild‐type p53 likely promotes the observed MDM2 coexpression.
• ? The results obtained in the present study suggest that the p53 pathway is altered in a tissue/disease‐specific manner and that therapeutic strategies targeting this pathway should be investigated to determine whether the tumour suppressive function of p53 can be rescued in RCC.

     

Prognostic value of apoptotic markers in squamous cell carcinoma of the urinary bladder

Study Type – Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Apoptotic pathways are important in carcinogenesis. Many studies, involving small numbers of patients, have found an association between one or two apoptotic markers and some of the pathological features of squamous cell carcinoma (SCC). This study included a large number of patients who had undergone radical cystectomy (RC) for SCC with long‐term follow‐up, allowing us to study biomarker alterations and their prognostic role. This is the first study on the prognostic role of a panel of apoptotic‐related markers in SCC of the urinary bladder, introducing the novel concept of a prognostic marker score based on the number of altered markers. We found that apoptotic markers can improve prediction of oncological outcomes after RC for SCC and might potentially help in patient selection for adjunct therapies.

OBJECTIVE

• ? To evaluate the association of cleaved caspase‐3 (CC‐3), Bax, COX‐2, and p53 expression with pathological features and clinical outcomes in patients with squamous cell carcinoma (SCC) of the urinary bladder.

METHODS

• ? Immunohistochemistry for CC‐3, Bax, COX‐2, and p53 was performed on tissue microarray sections of radical cystectomy specimens with pure SCC from 1997 to 2003. The relationship between the expression of these markers and pathological features was assessed.
• ? A prognostic marker score (PS) was defined as favourable if ≤2 biomarkers were altered and unfavourable if >2 biomarkers were altered and the association of the PS with oncological outcomes was examined.

RESULTS

• ? The study included 151 patients, of whom 98 were men and 53 were women, with a mean age of 52 years. SCC was associated with schistosomiasis (bilharziasis) in 122 (81%) patients.
• ? Pathological stage was T2 in 50%, T3 in 38%, T1 in 6% and T4 in 6% of patients. Tumours were low grade in 53%, lymph node metastasis was found in 30.5% and lymphovascular invasion was found in 16% of patients.
• ? Median follow‐up was 63.2 months.
• ? Advanced stage was associated with COX‐2, p53 and CC‐3 alterations and high grade was associated with COX‐2 alterations (P < 0.05). The total number of altered markers and unfavourable PS were associated with both disease recurrence and bladder cancer‐specific mortality in Kaplan–Meier analyses (P < 0.05). Unfavourable PS was an independent predictor of disease recurrence (hazard ratio [HR] 2.694, 95% confidence interval [CI] 1.386–5.235, P= 0. 003) and bladder cancer‐specific mortality (HR 2.868, 95% CI 1.209–6.802, P= 0. 017) in multivariable Cox regression analysis.

CONCLUSION

• ? Markers of apoptosis pathways may play an important role in the prognosis of SCC of the bladder. An increased number of altered markers and an unfavourable PS may identify patients who might benefit from multimodal therapies.

     

The predictive value of p53, p27(kip1), and alpha-catenin for progression in superficial bladder carcinoma

Objective

The aim of the study was to confirm the predictive value of cell cycle regulatory proteins, p53 and p27^kip1, and the cell adhesion complex protein α-catenin, for progression in patients with superficial bladder carcinoma.

Methods

Forty-one patients with progression after primary superficial bladder carcinoma were individually matched to patients with nonprogressive superficial bladder carcinoma. Matching was done for sex, age, tumor stage and grade, concomitant carcinoma in situ (CIS), and duration of follow-up. Immunohistochemical analysis of p53, p27^kip1, and α-catenin was performed on each primary bladder tumor. Analysis for the p53 mutation was done on 41 bladder tumor samples. Conditional logistic regression analysis was used to establish the prognostic value of immunohistochemical p53, p27^kip1, and α-catenin status.

Results

The independent odds ratios for progression were 0.3 (95% confidence interval [CI], 0.1–1.2) for high-risk p27^kip1, 3.4 (95%CI, 0.8–15.2) for high-risk p53, and 2.5 (95%CI, 0.6–10.3) for high-risk α-catenin. Combinations of different markers had no synergistic effects. Two p53 mutations were found in 21 DNA samples analyzed from nonprogressive tumors (9.5%); 8 of 20 samples (40%) from progressive tumors showed a p53 mutation. The probability of high-risk p53 immunostaining was 5-fold increased in case of mutations in p53. The estimated positive predictive value of high-risk p53 or high-risk α-catenin was about 23%.

Conclusions

We confirm that high-risk p53, p53 mutation, and α-catenin immunohistochemistry do have an additional prognostic value in primary bladder carcinoma. However, the clinical value of the investigated parameters remains limited.     

Tissue-specific deletion of the retinoblastoma protein in the pancreatic beta-cell has limited effects on beta-cell replication, mass, and function

Animal studies show that G(1/S) regulatory molecules (D-cyclins, cdk-4, p18, p21, p27) are critical for normal regulation of beta-cell proliferation, mass, and function. The retinoblastoma protein, pRb, is positioned at the very end of a cascade of these regulatory proteins and is considered the final checkpoint molecule that maintains beta-cell cycle arrest. Logically, removal of pRb from the beta-cell should result in unrestrained beta-cell replication, increased beta-cell mass, and insulin-mediated hypoglycemia. Because global loss of both pRb alleles is embryonic lethal, this hypothesis has not been tested in beta-cells. We developed two types of conditional knockout (CKO) mice in which both alleles of the pRb gene were inactivated specifically in beta-cells. Surprisingly, although the pRb gene was efficiently recombined in beta-cells of both CKO models, changes in beta-cell mass, beta-cell replication rates, insulin concentrations, and blood glucose levels were limited or absent. Other pRb family members, p107 and p130, were not substantially upregulated. In contrast to dogma, the pRb protein is not essential to maintain cell cycle arrest in the pancreatic beta-cell. This may reflect fundamental inaccuracies in models of beta-cell cycle control or complementation for pRb by undefined proteins.     

Prognostic implications of aberrations in p16/pRb pathway in urothelial bladder carcinomas: a multivariate analysis including p53 expression and proliferation markers

OBJECTIVE: To assess the prognostic value of the expression of two negative regulators of the cell cycle, namely CDKN2/INK4a gene product (p16) and retinoblastoma gene product (pRb), in urinary bladder cancer in relation to clinicopathological parameters, proliferative fraction and p53 protein accumulation. METHODS: Paraffin sections from 139 patients with urothelial carcinomas were stained immunohistochemically with antibodies to p16 (F12), pRb (PMG3-245), p53 (DO1), PCNA (PC10) and Ki-67 (MIB-1). RESULTS: Diminished p16 and pRb expression occurred in 29 and 74% of cases, respectively, being associated with advanced stage but not with histological grade, papillary status or proliferation rate. In most cases (53%) with some fault in the p16/pRb pathway, only one gene was affected. A double-negative p16/pRb phenotype was comparatively uncommon (25%) and was usually seen in T3-T4 tumours. In survival analysis (either univariate or multivariate) aberrant p16 expression was an adverse prognostic parameter only in T3-T4 tumours. In contrast, the abnormal p16/pRb and p53/p16 phenotypes were linked to a diminished overall and disease-free survival (univariate analysis); p53/p16 abnormal expression was also found to be an independent predictor of reduced survival in muscle-invasive tumours, while proliferation markers were the only parameters with independent significance in superficial (Ta-T1) tumours. CONCLUSION: Our results suggest that lack of p16 immunoexpression, when combined with p53 accumulation, plays an important role in determining the clinical outcome in muscle-invasive urothelial carcinomas.     

Biomarkers for predicting the response of esophageal squamous cell carcinoma to neoadjuvant chemoradiation therapy

This review summarizes and evaluates the literature regarding the biomarkers for predicting the response and/or prognosis of esophageal squamous cell carcinoma (ESCC) patients treated with neoadjuvant chemoradiation therapy (CRT). There are seven categories of molecules known to correlate with the response and/or prognosis: tumor suppressors (p53, p21), cell cycle regulators (Cyclin D1, CDC25B, 14-3-3sigma), DNA repair molecules (p53R2, ERCC1), drug resistance proteins [metallothionein (MT)], angiogenic factors (VEGF), molecules involved in cell proliferation/invasion/metastasis (Ki-67, COX-2) and hedgehog signaling molecules (Gli-1). Of the above molecules, the tumor suppressor p53 is expected to be a representative biomarker for predicting the response and prognosis. The cell cycle markers CDC25B and 14-3-3sigma have potential as response biomarkers independent of the p53 status. The DNA repair markers, p53R2 or ERCC1, angiogenic molecule (VEGF), and hedgehog signaling pathway factor Gli-1 also have potential to predict the response and prognosis of ESCC. However, there are still many unanswered questions with regard to predicting the clinical effects of neoadjuvant CRT.     

HPV Status of Oropharyngeal Cancer by Combination HPV DNA/p16 Testing: Biological Relevance of Discordant Results

Background and Purpose

Human papillomavirus (HPV) causes up to 70 % of oropharyngeal cancers (OSCC). HPV positive OSCC has a more favorable outcome, thus HPV status is being used to guide treatment and predict outcome. Combination HPV DNA/p16^ink4 (p16) testing is commonly used for HPV status, but there are no standardized methods, scoring or interpretative criteria. The significance of discordant (HPV DNA positive/p16 negative and HPV DNA negative/p16 positive) cancers is controversial. In this study, 647 OSCCs from 10 Australian centers were tested for HPV DNA/p16 expression. Our aims are to determine p16 distribution by HPV DNA status to inform decisions on p16 scoring and to assess clinical significance of discordant cancers.

Methods

HPV DNA was identified using a multiplex tandem HPV E6 polymerase chain reaction (PCR) assay and p16 expression by semiquantitative immunohistochemistry.

Results

p16 distribution was essentially bimodal (42 % of cancers had ≥70 % positive staining, 52 % <5 % positive, 6 % between 5 and 70 %). Cancers with 5 to <50 % staining had similar characteristics to the p16 negative group, and cancers with 50 to <70 % staining were consistent with the ≥70 % group. Using a p16 cut-point of 50 %, there were 25 % HPV DNA positive/p16 negative cancers and 1 % HPV DNA negative/p16 positive cancers. HPV DNA positive/p16 negative cancers had outcomes similar to HPV DNA negative/p16 negative cancers.

Conclusions

50 % is a reasonable cut-point for p16; HPV DNA positive/p16 negative OSCCs may be treated as HPV negative for clinical purposes; HPV DNA/p16 testing may add no prognostic information over p16 alone.

     

The combination of docetaxel and the somatostatin analogue lanreotide on androgen-independent docetaxel-resistant prostate cancer: experimental data

OBJECTIVE

To evaluate the effects of the association between docetaxel and the somatostatin analogue lanreotide on the androgen‐independent prostate cancer cell line PC3, either sensitive or made resistant to docetaxel (PC3R), as new drugs and new combinations have promising clinical activity in hormone‐refractory prostate cancer.

MATERIALS AND METHODS

We examined the effect of docetaxel and lanreotide on cell proliferation, with analysis of the mitogen‐activated protein kinase pathway and expression of cell‐cycle regulatory proteins.

RESULTS

Combined treatment with docetaxel and lanreotide inhibited PC3 cell growth in vitro through an enhanced induction of cell death, compared with treatment with either agent alone; this result was particularly evident on PC3R cells. The results suggested that lanreotide could act as a P glycoprotein inhibitor in PC3R cells.

CONCLUSION

The present results provide a promising therapeutic approach for using somatostatin analogues in hormone‐refractory prostate cancer, in which lanreotide could interact with docetaxel in PC3R cells, with possible explanatory mechanisms which involve P glycoprotein‐mediated docetaxel resistance.