DNA ploidy and survival of patients with clinically localized prostate cancer treated without intent to cure

Telomerase RNA Expression and DNA Ploidy as Prognostic Markers of Prostate Carcinomas

Aims and Background

The objective of this study was to determine whether there was a correlation between telomerase RNA expression and DNA ploidy status with clinicopathological parameters and biochemical recurrence after radical prostatectomy.

Study Design

Telomerase RNA expression and DNA ploidy were evaluated in imprint smear samples obtained from 112 prostates after radical prostatectomy. The results were correlated with pathological stage, Gleason score and serum PSA.

Results

Positive telomerse RNA expression was detected in 67.8% of prostate carcinomas. The multiple linear regression model showed a statistically significance increase in telomerase RNA expression with increased Gleason score ( P <0.0001) and preoperative serum PSA values ( P = 0.0125). DNA ploidy status also varied significantly with Gleason score ( P <0.0001) and preoperative serum PSA values ( P = 0.0110). Five patients with diploid tumors and negative telomerase RNA expression developed a recurrence. However, recurrence was associated with DNA aneuploidy ( P = 0.001) as well as with high telomerase RNA overexpression ( P = 0.001).

Conclusions

We conclude that telomerase RNA expression and DNA ploidy could be additional markers in the field of prognosis of prostate carcinomas.

Mature adipocytes observed to undergo reproliferation and polyploidy

Lipid‐filled mature adipocytes are important for the study of lipid metabolism and in the development of obesity, but whether they are capable of reproliferation is still controversial. Here, we monitored lipid droplet dynamics and adipocyte reproliferation in live, differentiated 3T3‐L1 cells using a phase‐contrast microscope in real time. Phase‐contrast microscopy achieves a similar visual effect in situ to that obtained using traditional dyes such as Oil Red O and BODIPY in vitro. Using this method, we captured the process that lipid droplets use for dynamic fusion in living cells. Unexpectedly, we acquired images of the moment that differentiated 3T3‐L1 cells containing lipid droplets entered mitosis. In addition, we observed some binucleated mature adipocytes. This information provides a better understanding of the adipocyte differentiation process.

In Treating Localized Prostate Cancer the Efficacy of Cryoablation is Independent of DNA Ploidy Type

While the prognostic value of DNA ploidy has been well established for radical prostatectomy, external beam radiation, brachytherapy and androgen deprivation therapy its role as a survival outcome predictor for prostate cancer patients treated with cryoablation has not yet been examined. Anecdotal evidence suggesting that cryoablation may be independent of DNA ploidy type led to the implementation of the current study. Retrospective analysis of data including flow digital cytometry was performed on 447 archival specimens taken from patients who had undergone cryosurgical ablation of primary prostate cancer. Five-year biochemical disease free survivals (bDFS) (defined as PSA thresholds of 0.5 and 1.0 ng/ml) were determined with Kaplan-Meier analysis. Patients were grouped according to DNA ploidy types then stratified by Gleason grade, risk group, pre-surgical PSA level, and disease stage.

Mean and median age of the cohort was 65 and 64.6 years. Mean follow-up was 65.7 months. The DNA ploidy status of the population was found to be 59% diploid, 13% tetraploid, and 28% aneuploid. Using PSA < 1.0 ng/ml criterion, the bDFS rates for diploid, tetraploid, and aneuploid were 78%, 75%, and 79% respectively. The bDFS rates using a PSA < 0.5 ng/ml criterion were 67%, 59%, and 69% for diploid, tetraploid, and aneuploid groups. No significant outcome differences were found in stratified analysis. This investigation demonstrates that the efficacy of cryoablation is independent of DNA ploidy type.

Expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin in localized prostate cancer

OBJECTIVE

To explore the correlation between the expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin in prostate cancer (PCa) and its clinicopathological data including tumor grade and clinical stage.

METHODS

The expression of α5-integrin, α7-integrin, Ε-cadherin, and N-cadherin was examined in 157 cases of PCa and adjacent normal prostatic tissue by immunohistochemical assay, and the correlation with clinicopathological features was analyzed.

RESULTS

Expressions of α5-integrin, α7-integrin, and Ε-cadherin in PCa were lower than those in normal prostatic tissues (P<0.05). N-cadherin expression was higher in cancer prostatic tissue than in normal prostatic tissues (P<0.05). The reduced expression of α5-integrin, α7-integrin, and Ε-cadherin was related to Gleason score, pathological stage, lymph node metastasis, and prostate-specific antigen level, but it was not associated with positive surgical margins and patient age. The increased expression of N-cadherin was related to Gleason score, pathological stage, lymph node metastasis, and prostate-specific antigen level, but not to age and positive surgical margins. The expression of E-cadherin was highly negatively correlated with that of N-cadherin and also positively correlated with that of α5-integrin and α7-integrin.

CONCLUSION

The reduced expression of α5-integrin, α7-integrin, and Ε-cadherin and abnormal expression of N-cadherin play an important role in the occurrence and development of PCa. The results indicate that these have potential values in the diagnosis and are predictable indices in the proliferation of PCa.

MicroRNA 100: a context dependent miRNA in prostate cancer

OBJECTIVE

MicroRNAs are noncoding RNA molecules involved in the development and progression of tumors. We have found that miRNA-100 is underexpressed in metastatic prostate cancer compared to localized disease. Conversely higher levels of miR-100 are related to biochemical recurrence after surgery. This suggests that miR-100 may be a context-dependent miRNA, acting as oncogene or tumor suppressor miRNA. Our aim is to demonstrate the role of miR-100 in the control of predicted target genes in prostate cancer cell lines.

METHODS

Cell lines DU145 and PC3 were transfected with miR-100, antimiR-100 and after 24 h and 48 h of exposure, qRT-PCR and western blot were performed for mTOR, FGFR3, THAP2, SMARCA5 and BAZ2A.

RESULTS

There was reduction in mTOR (p=0.025), THAP2 (p=0.038), SMARCA5 (p=0.001) and BAZ2A (p=0.006) mRNA expression in DU145 cells after exposure to miR-100. In PC3 cells, mTOR expression was decreased by miR-100 (p=0.01). There was a reduction in the expression levels of proteins encoded by studied genes, ranging from 34% to 69%.

CONCLUSIONS

We demonstrate that miR-100 is a context-dependent miRNA controlling BAZ2, mTOR, FGFR3, SMARCA5 and THAP2 that might be involved in PC progression. The elucidation of the roles of miRNAs in tumors is important because they can be used as therapeutic targets in the future.

TMPRSS2-ERG gene fusion is not associated with outcome in patients treated by prostatectomy

A significant number of prostate cancers have been shown to have recurrent chromosomal rearrangements resulting in the fusion of the androgen-regulated TMPRSS2 promoter to a member of the ETS transcription factor family, most commonly ERG. This results in ERG overexpression, which may have a direct causal role in prostate tumorigenesis or progression. However, the clinical significance of the rearrangement is unclear, and in particular, relationship to outcome has been inconsistent in recent reports. We analyzed TMPRSS2-ERG gene rearrangement status by fluorescence in situ hybridization in 521 cases of clinically localized surgically treated prostate cancer with 95 months of median follow-up and also in 40 unmatched metastases. Forty-two percent of primary tumors and 40% of metastases had rearrangements. Eleven percent had copy number increase (CNI) of the TMPRRS2-ERG region. Rearrangement alone was associated with lower grade, but not with stage, biochemical recurrence, metastases, or death. CNI with and without rearrangement was associated with high grade and advanced stage. Further, a subgroup of cancers with CNI and rearrangement by deletion, with two or more copies of the deleted locus, tended to be more clinically aggressive. DNA index assessment revealed that the majority of tumors with CNI of TMPRSS2-ERG had generalized aneuploidy/tetraploidy in contrast to tumors without TMPRSS2-ERG CNI, which were predominantly diploid. We therefore conclude that translocation of TMPRSS2-ERG is not associated with outcome, and the aggressive clinical features associated with CNI of chromosome 21 reflect generalized aneuploidy and are not due to CNI specifically of rearranged TMPRSS2-ERG.

Prognostic value of Her-2/neu and DNA index for progression, metastasis and prostate cancer-specific death in men with long-term follow-up after radical prostatectomy

Abnormal DNA content in tumor cells represents large scale chromosomal alterations and reflects later changes of genetic instability. Her-2/neu oncogene is amplified in 20-30% of breast and ovarian cancer patients and is associated with poor prognosis. Therefore, we evaluated prognostic value of Her-2/neu expression and DNA content measurements in 252 clinically localized PCa patients with long-term follow-up after radical prostatectomy for progression, metastasis and PCa-specific death. Her-2/neu expression was determined by immunohistochemistry and DNA content measurements employed Feulgen-stained cancer nuclei captured using static image cytometry system. Cox proportional hazard regression and Kaplan-Meir plots were used to identify significant prognostic factors for progression, metastasis and PCa-specific death. The proportions of Her-2/neu positive and high %DNA index tumors significantly increased from nonprogressor to progressors without metastasis to progressors with metastasis (p < 0.0001; <0.0001). Further, the proportions of Her-2/neu positive and high %DNA index tumors significantly increased from patients who died from another cause without progression to those who died from another cause with progression to those died with PCa-specific death (p = 0.027; <0.0001). Her-2/neu expression and %DNA index were significant prognosticators for progression (p <or= 0.001), metastasis (p <or= 0.01) PCa-specific death (p <or= 0.04) in univariate analyses. Multivariately, Her-2/neu expression and %DNA index were also significant for progression (p = 0.001), metastasis (p = 0.001) and PCa-specific death (p = 0.02). When all other clinicopathologic information is available, the increment in concordance index by addition of either Her-2/neu or DNA index was approximately 2% and of both biomarkers was approximately 3% for progression, metastasis and PCa-specific death free survival models. Therefore, patients with Her-2/neu positive and high %DNA index are at a higher risk for disease progression, metastasis and PCa-specific death. Further, Her-2/neu expression and %DNA index may be used with clinicopathologic parameters for prediction of long-term prognosis in PCa.

Homozygous deletions and recurrent amplifications implicate new genes involved in prostate cancer

Prostate cancer cell lines provide ideal in vitro systems for the identification and analysis of prostate tumor suppressors and oncogenes. A detailed characterization of the architecture of prostate cancer cell line genomes would facilitate the study of precise roles of various genes in prostate tumorigenesis in general. To contribute to such a characterization, we used the GeneChip 500K single nucleotide polymorphic (SNP) array for analysis of genotypes and relative DNA copy number changes across the genome of 11 cell lines derived from both normal and cancerous prostate tissues. For comparison purposes, we also examined the alterations observed in the cell lines in tumor/normal pairs of clinical samples from 72 patients. Along with genome-wide maps of DNA copy number changes and loss of heterozygosity for these cell lines, we report previously unreported homozygous deletions and recurrent amplifications in prostate cancers in this study. The homozygous deletions affected a number of biologically important genes, including PPP2R2A and BNIP3L identified in this study and CDKN2A/CDKN2B reported previously. Although most amplified genomic regions tended to be large, amplifications at 8q24.21 were of particular interest because the affected regions are relatively small, are found in multiple cell lines, are located near MYC, an oncogene strongly implicated in prostate tumorigenesis, and are known to harbor SNPs that are associated with inherited susceptibility for prostate cancer. The genomic alterations revealed in this study provide an important catalog of positional information relevant to efforts aimed at deciphering the molecular genetic basis of prostate cancer.

The 20-Yr Outcome in Patients with Well- or Moderately Differentiated Clinically Localized Prostate Cancer Diagnosed in the Pre-PSA Era: The Prognostic Value of Tumour Ploidy and Comorbidity

OBJECTIVE

This observational cohort study describes the long-term outcome of patients with clinically localized prostate cancer managed with watchful waiting, the prognostic value of tumour ploidy, and the impact of comorbidity.

METHODS

A total of 119 patients with clinically localized (T1-2) prostate cancer consecutively diagnosed from 1978 to 1982 were prospectively managed by watchful waiting, with treatment given if progression occurred.

RESULTS

Median age was 68 yr. Median observation time was 24 yr+/-6.25 (SD). Of the 112 patients who died, 42 died of prostate cancer. Disease-specific survival rates were 85% (95% CI: 77-93%), 58% (46-70%), and 32% (19-46%) at 10, 15, and 20 yr, respectively. Treatment-free survival rate was 43% (95% CI: 33-54%) at 10 yr. Patients aged 70 yr and over had a statistically significant increased risk of dying from any cause. There was a statistically significant increased risk of dying from prostate cancer for patients with nondiploid tumours.

CONCLUSION

In the present series from the pre-PSA era, watchful waiting yielded a relatively high long-term disease-specific survival rate in patients with well- or moderately differentiated clinically localized prostate cancer, and almost half were not treated 10 yr after diagnosis. Watchful waiting may be an option at least for such patients with a 10- to 15-yr life expectancy. Age of 70 yr or more predicted an increased overall mortality. High comorbidity increased the risk (although not statistically significant) for death from any cause and for death from prostate cancer. Patients with nondiploid tumours were at an increased risk to die from prostate cancer.

Prognostic Value of DNA Ploidy, bcl-2 and p53 in Localized Prostate Adenocarcinoma Incidentally Discovered at Transurethral Prostatectomy

PURPOSE

Discovery of prostatic adenocarcinoma limited to transurethral resection material generates a treatment dilemma. We investigated the usefulness of parameters shown to be associated with prognosis in prostate cancer (p53 and bcl-2 immuno-expression, DNA cell cycle analysis and Gleason score) to stratify these incidentally identified tumors to guide clinical decision making.

MATERIALS AND METHODS

Paraffin embedded tissues from transurethral prostate resection specimens containing T1a prostate adenocarcinoma from 44 patients who underwent resection between 1980 and 1990 were immunostained for p53 and bcl-2, and subjected to flow cytometry to determine DNA ploidy. Gleason score was determined by 2 pathologists independently. Statistical relationships among these 4 variables, tumor progression and cancer specific survival were analyzed.

RESULTS

Six of 44 patients in the study population had cancer progression. Time to clinical progression was 4.5 years (range 7 months to 11 years). Most tumors stained negative for p53 and bcl-2. Only 2 tumors studied were aneuploid and neither of these 2 patients had cancer progression. Only Gleason score was a significant predictor of cancer progression on univariate and multivariate Cox regression analysis (p = 0.045 and 0.046, respectively). No tumor characteristics correlated with time to disease progression, including p53 and bcl-2 immuno-expression, and Gleason score (p = 0.182, 0.563 and 0.346, respectively). Positive immunostaining for p53 and bcl-2 did not occur together in the same tumor in significant fashion (p = 0.334), nor did either significantly occur more with aneuploidy (p = 0.237 and 0.307 respectively).

CONCLUSIONS

For T1a prostate cancer incidentally detected on transurethral prostate resection p53 and bcl-2 immuno-expression, and DNA ploidy do not predict survival or disease progression.

Continuing controversy over monitoring men with localized prostate cancer: a systematic review of programs in the prostate specific antigen era

PURPOSE

There is continuing controversy over the most appropriate treatment for screen detected and clinically localized prostate cancer, and increasing interest in monitoring such men initially with radical treatment targeted at cancers showing signs of progressive potential but while they are still curable. Current evidence on monitoring protocols and biomarkers used to predict disease progression was systematically reviewed.

MATERIALS AND METHODS

The MEDLINE and Excerpta Medica (EMBASE) bibliographic databases were searched from 1988 to October 2004, supplemented by manual searches of reference lists, focusing on studies reporting monitoring of men with localized prostate cancer.

RESULTS

A total of 48 potentially eligible articles were found but only 5 studies, in which there was a total of 451 participants, restricted entry criteria to men with clinically localized (T1-T2) prostate cancer. Monitoring protocols varied with little consensus, although the majority used prostate specific antigen and digital rectal examination, while some added re-biopsy to assess progression. Actuarial probabilities of freedom from disease progression at 4 to 5 years of followup were 67% to 72%. However, up to 50% of men abandoned monitoring within 2 years, largely because of anxiety related to increasing prostate specific antigen rather than objective evidence of disease progression. There was no robust evidence to support prostate specific antigen doubling times or velocity to identify men in whom disease may progress. Studies were characterized by small sample size, short-term followup, observer bias and uncertain validity around variable definitions of progression.

CONCLUSIONS

Current evidence suggests that some form of monitoring would be a suitable treatment option in men with localized prostate cancer but there is little consensus over what markers should be used in such a program or how progression should be properly defined. The search for a method that safely identifies men with prostate cancer who could avoid radical intervention must continue.

Tetraploidy/aneuploidy and stem cells in cancer promotion: The role of chromosome passenger proteins

While polyploidy, a state of having fully duplicated sets of chromosomes per cell, has been described in normally developing bone marrow megakaryocytes or as an adaptive response in other cell types, aneuploidy is never detected in normal cells. Tetraploidy or aneuploidy can be induced by several signals and it is highly prevalent in different forms of cancers, suggesting a role for this cell cycle state in promoting cellular transformation. Investigations suggested that loss of heterozygosity of cancer-related genes in stem cells might contribute to genetic instability in progeny cells and to subsequent cancer development. Deregulated expression of chromosome passenger proteins, such as Aurora kinases or Survivin, is a hallmark of various cancers, and experimentally induced changes in these regulators can promote tetraploidy or aneuploidy and loss of heterozygosity. Our studies described an induction of tetraploidy/aneuploidy by a stable form of Aurora-B, leading to acquisition of transformation properties. It is intriguing to speculate that in some cancers, tetraploidy/aneuploidy induced by deregulated expression of a mitotic regulator represents a primary event that leads to unbalanced expression of a cluster of crucial genes and to cellular transformation.

The prognostic significance of the tumour infiltrating lymphocyte count in stage I testicular seminoma managed by surveillance

The degree of lymphocytic infiltration is a significant determinant of outcome for a variety of malignancies, but its role in seminoma is unknown. 150 men with stage I testicular seminoma presenting between 1981 and 1993 were managed by surveillance following orchidectomy. The presence of tumour infiltrating lymphocytes (TILs) in each case was classified as high, intermediate or low. At a median follow-up of 9.4 years, 30 of the 150 men developed recurrent seminoma. On univariate analysis, the risk of relapse was associated with age < or =33 years (P=0.002), tumour diameter >6 cm (P=0.03), lymphatic or vascular invasion (P=0.04), tumour invasion of rete testis (P=0.05), and lower TIL count (P=0.02). On multivariate analysis, statistically significant predictors of risk of relapse were age < or =33 years (hazard ratio (HR) 4.6 (95% confidence intervals (CI): 1.7-12.2)) and tumour diameter >6 cm (HR 2.8 (CI: 1.2-6.5)). Lower TIL count was of borderline statistical significance (HR 1.8 (CI: 0.96-3.44)). The functional role of the lymphocytic infiltrate in testicular seminoma warrants further study.

Prognostic value of DNA ploidy and nuclear morphometry in prostate cancer treated with androgen deprivation

OBJECTIVES

To assess the prognostic value of flow cytometry and nuclear morphometry in prostate cancer after androgen deprivation treatment.

METHODS

A total of 127 patients with a prostate cancer diagnosis who had undergone androgen suppression were retrospectively studied. The DNA content by flow cytometry and nuclear morphometry was studied from biopsy specimens. In the patients with Stage M0, two multivariate analyses by the Cox proportional regression model were performed to determine whether the experimental variables (DNA content and nuclear area) added independent information to the classic prognostic factors (Gleason score and stage). Using the statistical analysis results, risk groups were created.

RESULTS

T and M categories, Gleason score, DNA ploidy, and mean nuclear area proved to have prognostic value in the univariate analysis. For the group of patients free of metastasis (M0), it was possible to create low, intermediate, and high-risk groups using stage and Gleason score with statistically significant differences in survival. Multivariate analysis, combining the classic and experimental variables, selected Gleason score and DNA content as prognostic independent factors. Also, risk groups with statistically significant differences in survival were created. However, the net result of combining both kinds of factors was at least as valuable as the combination of stage and Gleason score in predicting survival.

CONCLUSIONS

The determination of DNA ploidy and mean nuclear area do not add enough independent information to improve the predictive value to justify their use in this group of patients treated with hormonal therapy.

Prognostic factors for survival of patients with pathological Gleason score 7 prostate cancer: differences in outcome between primary Gleason grades 3 and 4

PURPOSE

We evaluated differences in clinical and pathological outcomes between Gleason 3 + 4 and 4 + 3 prostate cancer.

MATERIALS AND METHODS

The radical prostatectomy whole mounted specimens from 263 men with pathological Gleason 7 tumors were identified. Gleason 3 + 4 and 4 + 3 tumors were compared in regard to pathological variables and outcome. Significance of clinical and pathological data on progression-free survival was analyzed.

RESULTS

Of the tumors 34% had a primary Gleason grade of 4, and were more likely than those with primary grade 3 to have seminal vesicle involvement (34% versus 18%, p = 0.006), a higher pathological stage (pT3 55% versus 42%, N+ 13% versus 3%, 0.001), extraprostatic extension (58% versus 38%, 0.001) and higher median preoperative prostate specific antigen (PSA) (13.5 versus 9.0 ng./ml., respectively <0.001). Mean followup plus or minus standard deviation was 6.8 +/- 1.9 years. The overall 10-year crude, cancer specific and progression-free survival rates were 83%, 99% and 58%, respectively. Primary Gleason grade was significantly associated with progression-free (risk ratio 1.6, 95% confidence interval 1.08 to 2.5, p = 0.02) but not crude and cancer-specific survival. Univariately, primary Gleason grade 4 was associated with progression-free survival, as were percent Gleason 4, seminal vesicle invasion, lymph node involvement, pT stage, margin status, DNA ploidy, preoperative PSA, cancer volume and extent of extraprostatic extension. Multivariately, only preoperative PSA (p <0.001), seminal vesicle invasion (<0.001) and DNA ploidy (0.002) were associated with progression-free survival. Primary Gleason grade and percent Gleason 4 were not identified as independently associated with progression-free survival.

CONCLUSIONS

In patients with Gleason 7 score prostate cancer primary Gleason grade 3 and 4 cancers are different in pathological parameters and prognosis. However, primary Gleason grade does not provide any additional information than other known prognostic factors, such as preoperative PSA, seminal vesicle invasion and DNA ploidy.

[Prognostic value of DNA ploidy in prostatic cancer]

OBJECTIVE

To asses the prognostic value of deoxyribonucleic acid (DNA) ploidy in a group of patients with prostate cancer treated with adrogenic blockade.

MATERIALS AND METHODS

A retrospective study on 136 patients with prostatic cancer having undergone androgenic blockade was carried out. The prognostic influence of age, T and M categories, Gleason score and flow cytometry-determined DNA ploidy from survival analyses. Univariate survival analysis was carried out following Kaplan-Meier's method, while for multivariate survival analysis Cox's proportional hazard model was used.

RESULTS

The univariante analysis showed that T and M categories, Gleason score and DNA ploidy have prognostic value. The Cox's regression analysis identified DNA ploidy, metastasis and Gleason score as independent variables having prognostic potential.

CONCLUSIONS

DNA ploidy has independent prognostic value in prostate cancer treated with androgenic blockade and improves the predictive potential of classical prognostic factors.

Can ploidy of prostate carcinoma diagnosed on needle biopsy predict radical prostatectomy stage and grade?

PURPOSE

Deoxyribonucleic acid ploidy correlates with the biological behavior of prostate carcinoma. However, the usefulness of ploidy on needle biopsies that show prostate cancer has not been established to our knowledge.

MATERIALS AND METHODS

We retrospectively determined ploidy on needle biopsies of 159 men with prostate carcinoma treated surgically at Johns Hopkins Hospital. Ploidy was determined by image analysis of Feulgen stained slides. Needle ploidy and Gleason score were compared as prognostic tools in the prediction of grade and stage of subsequent prostatectomy.

RESULTS

Of the 159 cases 98 (62%) were diploid, 16 (10%) tetraploid and 45 (28%) aneuploid. Of the diploid, tetraploid and aneuploid tumors 69, 50 and 44%, respectively, proved to be organ confined. Tetraploid and aneuploid tumors were grouped for the remaining analysis. Needle ploidy correlated significantly with pathological stage (p = 0.003). However, needle Gleason score correlated even more strongly (p <0.001), and on multivariate analysis ploidy was not further predictive of pathological stage once Gleason score was considered. Needle ploidy and Gleason score were predictive of prostatectomy Gleason score (6 or less versus 7 or greater), and on multivariate analysis ploidy was an independently significant predictor of this parameter (p = 0.04). In 13 cases (8%) there was an important grading discrepancy, in which needle ploidy would have accurately predicted prostatectomy grade. However, in 33 cases (21%) needle and prostatectomy Gleason scores were congruent, and needle ploidy did not accurately predict prostatectomy Gleason score.

CONCLUSIONS

With accurate needle Gleason grading, ploidy is not helpful in predicting prostatectomy findings. However, ploidy correlates with prostatectomy stage and grade, and may be useful if accurate Gleason grading is a concern.

E-cadherin expression as a marker of tumor aggressiveness in routinely processed radical prostatectomy specimens

OBJECTIVES

Approximately 30% of clinically localized prostate adenocarcinomas treated by radical prostatectomy (RP) will recur within 10 years. To prevent recurrence, new adjuvant therapies are in development that seek to treat high-risk patients after surgery. To identify patients as candidates for these treatments, improved biomarkers for predicting prognosis are needed. Reduced expression of E-cadherin has been proposed as a new marker for predicting prognosis in prostate adenocarcinoma. Since few studies have examined the relation between risk factors for disease progression and E-cadherin expression using routinely processed RP specimens, we used RP specimens to correlate downregulation of E-cadherin and pathologic stage at RP.

METHODS

Primary adenocarcinomas (n = 76) from formalin-fixed and paraffin-embedded RP specimens were evaluated by immunohistochemistry against E-cadherin (HECD-1) using heat-induced epitope retrieval and automated staining (BioTek Solutions). Normal appearing prostate epithelium was used as an internal control for each specimen. Staining was scored as an estimate of the percentage of tumor cells in each specimen that showed strong plasma membrane staining.

RESULTS

Specimens were divided into three categories with respect to Gleason score: intermediate (score 5 to 6, n = 31), intermediate to high (score 7, n = 25), and high (score 8 to 9, n = 20). For pathologic stage, specimens were divided into three categories: low stage/organ confined (pT2, n = 30), intermediate stage/limited extraprostatic extension (pT3a, n = 25), and high stage/seminal vesicle-pelvic lymph node metastases (pT3b-any pTN1, n = 21). In univariate analysis, reduced levels of E-cadherin correlated with advanced Gleason score (P = 0.003) and advanced pathologic stage (P = 0.008). In multivariate analysis, E-cadherin, preoperative prostate-specific antigen, and Gleason score all contributed independently to the prediction of high-stage disease (P<0.0001). Ten pelvic lymph node metastases from this same patient cohort were stained for E-cadherin. All were positive and 9 of 10 were moderately to strongly positive.

CONCLUSIONS

Since essentially all patients in the high-stage category have a very high likelihood of disease recurrence, we conclude that the study of E-cadherin in a prospective manner as a potential biomarker of disease progression in patients with clinically organ-confined prostate cancer who undergo RP is warranted. Additionally, our finding that most metastatic tumor cells in pelvic lymph nodes express E-cadherin supports the notion that the establishment of the distant colonization and growth of metastatic tumor cells may be facilitated by expression or re-expression of previously downregulated E-cadherin. This would strongly suggest that irreversible genetic inactivation through mutation or allelic loss at 16q2.3 is probably not the mechanism of E-cadherin downregulation in most abnormally expressing primary prostate carcinomas.