Quantitative ultrasound spectroscopic imaging for characterization of disease extent in prostate cancer patients

Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~5MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r(2) value of 0.71 (P<.0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r(2)=0.764, P<.05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation.

Utility of 5-alpha-reductase inhibitors in active surveillance for favourable risk prostate cancer

INTRODUCTION

This retrospective review compares prostate-specific antigen (PSA) doubling time (DT) prior to the initiation of a 5-alpha-reductase inhibitor (pre-5-ARI) to after the PSA nadir (post-nadir) has been reached for patients on active surveillance for favourable-risk prostate cancer.

METHODS

Between 1996 and 2010, a total of 100 men with a history of 5-ARI use were captured from our active surveillance database. Twenty-nine patients had a sufficient number of PSA values to determine both pre-5-ARI and post-nadir DTs. PSADT was calculated using the general linear mixed-model method.

RESULTS

The median follow-up was 69.5 months. The median pre-5-ARI PSADT was 55.8 (range: 6-556.8) months, while the post-nadir value was 25.2 (range: 6-231) months (p = 0.0081). Six patients were reclassified after an average of 67.7 (range: 59-95) months, due to progression in PSADT (n = 2) or Gleason score (n = 4). The median pre-5-ARI and post-nadir DTs for this group were 42.3 (range: 32.4-91.1) and 21.1 (range: 6-44.3) months, respectively.

CONCLUSION

5-ARIs significantly decreased PSADT compared to prior to their initiation. This effect may be due to preferential suppression of benign tissue following PSA nadir. The resulting PSADT would then represent a more accurate depiction of the true cancer-related DT. If validated with a larger cohort, 5-ARIs may enhance the utility of PSADT as a biomarker of disease progression in active surveillance.

Systematic review of complications of prostate biopsy

CONTEXT

Prostate biopsy is commonly performed for cancer detection and management. The benefits and risks of prostate biopsy are germane to ongoing debates about prostate cancer screening and treatment.

OBJECTIVE

To perform a systematic review of complications from prostate biopsy.

EVIDENCE ACQUISITION

A literature search was performed using PubMed and Embase, supplemented with additional references. Articles were reviewed for data on the following complications: hematuria, rectal bleeding, hematospermia, infection, pain, lower urinary tract symptoms (LUTS), urinary retention, erectile dysfunction, and mortality.

EVIDENCE SYNTHESIS

After biopsy, hematuria and hematospermia are common but typically mild and self-limiting. Severe rectal bleeding is uncommon. Despite antimicrobial prophylaxis, infectious complications are increasing over time and are the most common reason for hospitalization after biopsy. Pain may occur at several stages of prostate biopsy and can be mitigated by anesthetic agents and anxiety-reduction techniques. Up to 25% of men have transient LUTS after biopsy, and <2% have frank urinary retention, with slightly higher rates reported after transperineal template biopsy. Biopsy-related mortality is rare.

CONCLUSIONS

Preparation for biopsy should include antimicrobial prophylaxis and pain management. Prostate biopsy is frequently associated with minor bleeding and urinary symptoms that usually do not require intervention. Infectious complications can be serious, requiring prompt management and continued work into preventative strategies.

How does stereotactic body radiotherapy compare to standard external beam radiotherapy or low-dose rate brachytherapy for low-risk prostate cancer?

e16070

Background: Stereotactic body radiotherapy (SBRT) is an emerging radiotherapy technique that appears to be efficacious, well tolerated and convenient. However, outcomes for patients treated with SBRT are unknown compared to more conventional radiation options for patients with prostate cancer. The purpose of this study is to evaluate and compare late toxicities and biochemical disease-free survival (bDFS) of low risk prostate cancer patients treated SBRT (35Gy/5 fractions), standard external beam radiotherapy (STND; median 76Gy/38 fractions) or low-dose brachytherapy (LDR; iodine-125, 145Gy) at the Odette Cancer Centre. Methods: Consecutive patients with low risk prostate cancer treated with radiation from 2006-2008 were analyzed. Patients treated with SBRT were part of a phase 2 prospective clinical trial; patients treated with STND or LDR had data abstracted from medical charts retrospectively. Patients treated with neoadjuvant androgen deprivation therapy were excluded from biochemical analyses. Univariate (UVA) and multivariate analyses (MVA) of Cox proportional hazard model were conducted to identify significant covariates predicting bDFS. Results: A total of 357 low-risk prostate cancer patients were identified (84 SBRT, 81 STND and 192 LDR). The median follow-up was 57, 62, and 59 months, respectively. At baseline, 85% of patients were T1c, 15% T2a; 100% had GS 6; median PSA 5.9 ng/ml. There were more patients in the STND and LDR cohort who had T2a disease (6%, 21% and 16%, p= 0.013) and the mean PSA was higher in the STND cohort (6.08, 6.69, and 6.02, p=0.017). Patients who received LDR experienced more late hematuria (0%, 1.23% and 11.98%, p<0.0001); otherwise there were no significant differences in late toxicities observed. There were no significant differences in bDFS (97.4% vs 96.9% vs 97.2% at 60 months, p=0.94). There were no covariates identified predicting bDFS on UVA or MVA, including treatment type. Conclusions: SBRT, STND and LDR show equivalent effectiveness and both external beam techniques showed less hematuria than LDR. However, SBRT and LDR are more convenient and less costly than STND. Further prospective studies of SBRT are ongoing.

Quantifying copy number variations in cell-free DNA for potential clinical utility from a large prostate cancer cohort

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Background: Prostate cancer (PrCa) is the most frequent non-dermatological malignancy in the male population. Genomic instability resulting in copy number variation (CNV) is a hallmark of malignant transformation. CNV traces from tumors in cell-free DNA (cfDNA) of prostate cancer patients may be identified through massive parallel sequencing (MPS) of serum DNA. These CNV traces may be biomarkers of cancer with clinical applications for screening and follow-up. Methods: DNA was extracted from serum of 205 PrCa patients (Gleason 2 to10), 207 age matched male controls (HC), 10 men with benign hyperplasia (BPH) and 10 with prostatitis (PiS). DNA was amplified using random primers, tagged with a unique molecular identifier per sample, sequenced on a SOLiD system and aligned to the human genome (Build 37). Hits were counted in sliding 100kbp intervals and normalized. Using a random-resampling procedure, genomic regions showing copy number variations in cfDNA that distinguish PrCa from HC were selected. A model using 20 cfDNA regions was cross-validated and used as cfDNA biomarker. Receiver operator characteristics (ROC) curves were calculated for assessment of diagnostic performance by means of area under the curve (AUC). Results: To assess whether CNVs in cfDNA are indicative of PrCa, the number of regions with significant CNV deviation was counted in a first subset of 82 PrCa. Using only the number of regions as measure resulted in an AUC of 0.81 (0.7 – 0.9, p<0.001). Therefore, all samples were used to select regions (n=80) in random resampling (50/50). These regions were used to define a highly significant 20-regions model using five rounds of 10-fold cross-validation (AUC: 0.85±0.7; p< 10-7). This final model discriminated between PrCa and HC with an AUC of 0.92 (0.87 – 0.95) reaching a calculated accuracy of 83%. Both BPH and PiS could be distinguished from PrCa using the cfDNA CNV biomarker with a predicted accuracy of 90%. Conclusions: MPS revealed that only a limited number of chromosomal regions showing CNVs are necessary to achieve statistical separation between prostate cancer and controls. This technique may prove to be clinically useful for screening and follow up of men with prostate cancer.

Whole-transcriptome analysis reveals established and novel associations with TMPRSS2:ERG fusion in prostate cancer

BACKGROUND/AIM

Shortcomings of current methods of prostate cancer detection call for improved biomarkers. The transmembrane protease, serine 2:ets-related gene (TMPRSS2:ERG) gene fusion leads to the overexpression of ERG, an E-twenty six (ETS) family transcription factor, and is the most prevalent genetic lesion in prostate cancer, but its clinical utility remains unclear.

MATERIALS AND METHODS

Two radical prostatectomy samples were analysed by next-generation whole-transcriptome sequencing. The chosen samples differed in fusion gene status, as previously determined by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Next-generation sequencing identified the involvement of novel and previously reported prostate cancer-related transcripts, the WNT signalling pathway, evasion of p53-mediated anti-proliferation and several ETS-regulated pathways in the prostate cancer cases examined. Overexpression of Rho GDP-dissociation inhibitor (RhoGDIB), a gene associated with fusion-positive prostate cancer, was found to elicit spindle-shaped morphology, faster cell migration and increased cell proliferation, phenotypic changes suggestive of cancer progression.

CONCLUSION

The present findings confirm the value of comprehensive sequencing for biomarker development and provide potential avenues of future study.

Patient costs associated with external beam radiotherapy treatment for localized prostate cancer: the benefits of hypofractionated over conventionally fractionated radiotherapy

INTRODUCTION

To estimate the out-of-pocket costs for patients undergoing external beam radiotherapy (EBRT) for prostate cancer and calculate the patient-related savings of being treated with a 5-fraction versus a standard 39-fraction approach.

MATERIALS AND METHODS

Seventy patients accrued to the pHART3 (n = 84) study were analyzed for out-of-pocket patient costs as a result of undergoing treatment. All costs are in Canadian dollars. Using the postal code of the patient's residence, the distance between the hospital and patient home was found using Google Maps. The Canada Revenue Agency automobile allowance rate was then applied to determine the cost per kilometer driven.

RESULTS

The average cost of travel from the hospital and pHART3 patient's residence was $246 per person after five trips. In a standard fractionation regimen, pHART3 patients would have incurred an average cost of $1921 after 39 visits. The patients receiving hypofractionated radiotherapy would have paid an average of $38 in parking while those receiving conventional treatment would have paid $293. The difference in out-of-pocket costs for the patients receiving a standard versus hypofractionated treatment was $1930.

CONCLUSIONS

Medium term prospective data shows that hypofractionated radiotherapy is an effective treatment method for localized prostate cancer. Compared to standard EBRT, hypofractionated radiotherapy requires significantly fewer visits. Due to the long distance patients may have to travel to the cancer center and the expense of parking, the short course treatment saves each patient an average of $1900. A randomized study of standard versus hypofractionated accelerated radiotherapy should be conducted to confirm a favorable efficacy and tolerability profile of the shorter fractionation scheme.

Role of 5-alpha-reductase inhibitors in active surveillance of patients with low-risk prostate cancer

14

Background: Active surveillance (AS) is a recognized management option for low-risk prostate cancer. Many institutions use serial PSA values to determine when to reclassify patients into higher risk categories. The impact of 5-alpha-reductase inhibitors (5-ARIs) in this setting has not been well studied. The purpose of this retrospective review was to compare PSA doubling time prior to the initiation of a 5-ARI (pre-5-ARI) to that after the PSA nadir (post-nadir) has been reached.

Methods: Between 1996 and 2010, a total of 100 patients with a history of 5-ARI use were captured from our AS database. Of these, twenty-nine had a sufficient number of PSA values to determine both pre-5-ARI and post-nadir doubling times. The majority had stage T1c disease (89.7%) and Gleason scores of six or lower (93.1%). The average PSA at presentation was 6.93 µg/L. More patients were prescribed dutasteride (79.3%) than finasteride (20.7%). PSA doubling time was calculated using the general linear mixed-model method. Statistical analysis was performed using the non-parametric sign test.

Results: Median follow-up was 69.5 months (mo). For the twenty-nine patients analyzed, the median pre-5-ARI PSA doubling time was 55.8 mo (6-556.8 mo), while that for the post-nadir values was 25.2 mo (6-231 mo) (p=0.0081). Six patients were ultimately reclassified after an average of 67.7 mo (59-95 mo), due to progression in either PSA doubling time (n=2) or Gleason score (n=4). The median pre-5-ARI and post-nadir doubling times for this group were 48.2 mo (32.4-91.1 mo) and 23.3 mo (6-44.3 mo), respectively. Five of the patients underwent radical prostatectomy, while one underwent radiotherapy with androgen deprivation. Of the six patients, one had biochemical failure after an average post-treatment follow-up of 21.3 mo (0-52 mo).

Conclusions: In AS for low-risk prostate cancer, it was found that 5-ARIs significantly decreased PSA doubling time. This effect may be related to preferential suppression of benign prostatic tissue, thereby providing a more accurate depiction of the true cancer-related doubling time. If validated with a larger cohort, 5-ARIs may enhance the utility of PSA doubling time as a biomarker of disease progression in AS.

Three-dimensional ultrasound-based spectroscopic imaging for the detection of prostate cancer

234

Background: The objective of this translational research was to investigate the use of real-time novel three-dimension, quantitative ultrasound-based spectroscopic imaging of the prostate as a means of cancer detection.

Methods: Fourteen patients with T2-3 prostate cancer underwent a 6–9 MHz trans-rectal ultrasound scan of the prostate prior to radical prostatectomy. Equally spaced axial ultrasound images (0.5 cm separation) corresponding elasticity and spectroscopy data were collected in each patient. Colour-coded spectroscopic parametric maps of 0-Mhz intercept (0-Mhz), mid-band fit (MBF) and slope of line of best fit (slope) were generated indicating where the disease in the prostate gland is hypothetically located. Quantitative data (% volume of cancer over the prostate gland) were compared to whole-mount radical prostatectomy histopathology maps to determine the sensitivity and accuracy in parametrically delineating prostate cancer.

Results: Representative data indicate spectral changes were associated with the presence of co-incident disease as located on correlative histopathology whole mount sections. Of the 14 patients enrolled, 7 have been analyzed and presented here. The mean % difference between 0-MHz and MBF, with H&E, was 14% (SD 38%) and 21% (SD 24%), respectively. Gross areas of disease were readily visualized in ultrasound parametric maps and corresponded to a maximum 10dB decrease in 0-MHz or MBF. Parametric maps generated from the spectral slope offered no discrimination of disease. There were differences in scatterer size estimates and scatter concentration estimates between putative disease areas and the remaining tissue.

Conclusions: Initial results suggest that there is good correlation between spectroscopic maps with disease on whole-mount specimens. This method may ultimately permit ultrasound-guided targeted biopsies to improve detection rates and non-invasive assessment of disease for radiotherapy planning.

Personal digital assistant data capture: the future of quality of life measurement in prostate cancer treatment

PURPOSE

This article examines the potential use of personal digital assistant (PDA) data capture systems for real-time linear monitoring of health-related quality of life (HRQOL) in prostate cancer research and clinical care.

METHODS

We discuss the benefits and potential issues of using PDA data capture in the clinical health care setting. In addition, we describe the development and potential use of a PDA data capture system specific to managing HRQOL in prostate cancer treatment.

CONCLUSION

Follow-up health care clinics require a practical and systematic process of HRQOL data capture and analysis. Traditional paper questionnaire data capture is problematic. Data manipulation required for clinical decision-making is impractical for patient feedback on same-day clinic visits. Furthermore, the process of transforming paper questionnaire data to analysis-quality data can compromise data integrity. In contrast, research findings confirm the acceptability, ease of use, and reliability of PDAs in capturing data across health care settings, including the collection of serial HRQOL data. The main concern for PDA capture systems is the ability to compare respondent's answers between the paper and PDA questionnaire. Other challenges included patients reporting a lack of computer literacy and/or poor eyesight, as well as initial start-up costs. If issues are successfully addressed, the use of a PDA data capture system, such as the PDA HRQOL system at Princess Margaret Hospital's Prostate Centre, allows for valid and economical data collection with the possibility of linear real-time measurement of changes in HRQOL. Accordingly, there appears to be significant potential for PDA data collection of serial HRQOL in prostate cancer clinic settings.

Capsaicin may slow PSA doubling time: case report and literature review

Capsaicin is the main pungent component of chili peppers. This is the first case, to our knowledge, that describes prostate-specific antigen (PSA) stabilization in a patient with prostate cancer, who had biochemical failure after radiation therapy. A 66-year-old male underwent radiotherapy treatment for a T2b, Gleason 7 (3+4) adenocarcinoma of the prostate, with a PSA level of 13.3 ng/mL in April 2001. He had 3-dimensional conformal radiotherapy of 46 Gy in 23 fractions to the prostate and pelvis, and a prostate boost of 30 Gy in 15 fractions. Radiotherapy was completed in May 2001 and PSA nadired in January 2002 (0.57). Due to the continued PSA rise, the patient was started on bicalutamide (50 mg orally, daily) and leuprolide acetate (1 dose of 22.5 mg intramuscularly) in July 2005 when PSA was 38.5 ng/mL. Due to poor tolerance of androgen ablation therapy, the patient discontinued treatment and started taking 2.5 mL of habaneros chili sauce, containing capsaicin, 1 to 2 times a week in April 2006. Prostate-specific antigen doubling time (PSAdt) increased from 4 weeks before capsaicin to 7.3 months by October 2006. From October 2006 until November 2007, the patient remained on capsaicin (2.5 to 15 mL daily) and his PSA was stable (between 11 to 14 ng/mL). By January 2008, his PSA rose to 22.3 and he has maintained a PSAdt between 4 and 5 months, where it presently remains. Due to the patient's continued PSA rise, he was restarted on bicalutamide (12.5 mg daily). Apart from PSA relapse, the patient remains free of signs or symptoms of recurrence.

Got central prostate pathology review? A cross-sectional audit of 2009 versus 2003 outcomes

196

Background: Prostate cancer is the most common non-cutaneous cancer in Canadian men; over 24,000 will be newly diagnosed and 4,300 will die from it in 2010. Estimating an individual's risk of disease spreading across the capsule and probability of recurrence with different treatment modalities is common practice in prostate cancer management and often drive the choice or extent of treatment options. A strong predictor of recurrence and organ confined disease is tumor grade. The literature recognizes differences in grading prostate cancer between genitourinary and non-specialized pathologists; we previously reported a 30% change in risk category (Low, GS 2-6; Int., GS 7; High, GS 8-10). However, this report was based on data from 2003/2004. A repeat audit was necessary given Gleason grading practice changes following the 2005 ISUP Consensus Conference.

Methods: Log books from 2009/10 where our Genitourinary Pathologists (GUP) reviewed prostate needle core biopsies were used to identify cases; a retrospective chart review was completed. The following variables were extracted: 1° Gleason score; 2° Gleason score; number of sites; % Gleason 4/5 pattern (overall); perineural invasion (present/absent); extracapsular extension (present/absent). Descriptive statistics were used to summarize the results.

Results: The charts of 132 patients having a GUP biopsy review were extracted. Seventeen percent (22/132) of cases changed risk category. Of the 47 low risk cases, 23% (11/47) were up-graded in risk category (21% by 1 category; 2% by 2 categories). Of the 46 intermediate risk cases, 15% (7/46) were up-graded and 2% (1/46) were down-graded. Of the 39 high risk cases, only 8% (3/39) were down-graded by 1 risk category. Comparatively, there was a 43% reduction in risk category change between 2003/04 (30%) and 2009/10 (17%).

Conclusions: Despite this reduction, a clinically significant proportion of patients changed pathologic risk category upon GUP review. Thus, it is recommended that prostate cancer pathology be routinely reviewed by a GUP as a best practice to optimize management and quality of care. Strategies are still needed to address disparities in pathologic grading and represent a potential area for further investigation.

No significant financial relationships to disclose.

Three-dimensional ultrasound-based spectroscopic imaging for detection of prostate cancer in men

57

Background: The objective of this translational research was to investigate the use of real-time novel three-dimension, quantitative ultrasound-based spectroscopic imaging of the prostate as a means of cancer detection.

Methods: Ten patients with T2-3 prostate cancer underwent a 6-9 MHz trans-rectal ultrasound scan of the prostate prior to radical prostatectomy. Equally spaced axial ultrasound images (0.5 cm separation) corresponding elasticity and spectroscopy data were collected in each patient. Colour-coded spectroscopic parametric maps of 0-Mhz intercept (0-Mhz), mid-band fit (MBF) and slope of line of best fit (slope) were generated indicating where the disease in the prostate gland is hypothetically located. Quantitative data (% volume of cancer over the prostate gland) were compared to whole-mount radical prostatectomy histopathology maps to determine the sensitivity and accuracy in parametrically delineating prostate cancer.

Results: Representative data indicate spectral changes were associated with the presence of co-incident disease as located on correlative histopathology whole mount sections. Of the 10 patients enrolled, 7 have been analyzed and presented here. The mean % difference between 0-MHz and MBF, with H&E, was 14% (SD 38%) and 21% (SD 24%), respectively. Gross areas of disease were readily visualized in ultrasound parametric maps and corresponded to a maximum 10dB decrease in 0-MHz or MBF. Parametric maps generated from the spectral slope offered no discrimination of disease.

Conclusions: Initial results suggest that there is good correlation between spectroscopic maps with disease on whole-mount specimens. This method may ultimately permit ultrasound-guided targeted biopsies to improve detection rates and non-invasive assessment of disease for radiotherapy planning.

No significant financial relationships to disclose.

A review of radical prostatectomy outcomes in active surveillance patients—The Sunnybrook experience

104

Background: Prostate cancer is the most prevalent non-cutaneous cancer among North American men. Approximately 50% of these are favorable risk cancers; the NCCN guideline recommends active surveillance for these patients. Patients are generally followed by serial PSAs, DREs and/or TRUS-guided biopsies with triggers identified for each test. Consequently, about 30% of these cancers will be reclassified to a higher risk and require definitive treatment. Cases treated with radical prostatectomy (rP) give important insights into the biology of these cancers.

Methods: The ASURE database of active surveillance patients was used to identify cases; a retrospective chart review was completed. The following variables were extracted: primary reason for rP; % biochemical failure; % of patients requiring salvage radiation or hormone therapy; Gleason score (GS), tumor size staging and nodal status in the rP specimen; cause and rate of mortality; proportion of patients treated for PSA-doubling times less then 3 years presenting with a GS greater than 7. Descriptive statistics were used to summarize the results.

Results: Of 566 patients in the ASURE database, the charts of 26 patients having an rP were extracted. The primary cause for an rP was a PSA-doubling times less than 3 years (57% of patients) followed by a biopsy indicating a GS of 4+3 or greater (19%). 7% of patients (2/26) were not reclassified but preferred to be treated with rP. 4 patients had biochemical failure (15%) all 4 had salvage therapy. There was 1 cause-specific death. 85% of rP specimens had GS 7, while the remaining had GS 6. Half of these GS 7 individuals had PSA doubling times of less than 3 years.

Conclusions: Radical prostatectomy appears to be an effective deferred treatment for patients who are reclassified on active surveillance as evidenced by low prostate-cancer mortality, low rates of biochemical failure acceptable use of salvage therapy. Of interest is that the majority patients with PSAdt < 3 y have Gleason 7 disease on specimen.

No significant financial relationships to disclose.

Abstract 4035: MicroRNA-221 levels correlate with aggressive and clinically recurrent prostate cancers

One of the most important challenges in prostate cancer research is to identify biomarkers that are predictive of cancer aggressiveness and future tumor recurrence following radical prostatectomy. Recent studies have shown that altered expression of microRNAs (miRs) is involved in the development of prostate cancer, and among the differentially expressed miRNAs, miR-221 may be critical in metastatic induction/regulation. While the precise role of this miRNA in facilitating malignant progression remains unclear, expression of miR-221 in prostate cancer may correlate with disease state/status and serve as a surrogate biomarker for tumor recurrence and/or aggressiveness. In the present study, we sought to investigate whether miR-221 is differentially regulated in patients with aggressive and non-aggressive tumors relative to control normal prostate cell line RWPE-1 and, more specifically, whether this miRNA can be used as biomarker for disease recurrence. To address this question, we initially chose to assess the relative expression of miR-221 in a series of aggressive (n=69) and non-aggressive (n=45) primary carcinoma tissues derived from clinically resected prostates by quantitative real-time PCR. Aggressive tumors were categorized based on clinicopathological parameters such as Gleason score of 8 or higher, high PSA levels, presence of metastasis, invasion to the seminal vesicles, and recurrence after radical prostatectomy. Relative expression of mature miR-221 in tumors was quantified in comparison to control prostate epithelial cell line, RWPE-1, which was set to be 1x. Levels of miR-221 expression were found to be variable. Among all aggressive and non-aggressive cancer patients, expression of miR-221 transcript levels was differentially expressed relative to control sample. However, when we divided this group of patients on the basis of miR-221 expression levels, 72% of the patients with aggressive tumors had miR-221 less than 5-fold the RWPE-1 levels and only 28% of the patients had miR-221 expression equal to or more than 5-fold RWPE-1 levels. On the other hand, 53% of the patients with non-aggressive tumors had miR-221 less than 5-fold the RWPE-1 levels compared to 47% of the patients with miR-221 equal to or more than 5-fold RWPE-1 levels. Our results show that miR-221 is lower in majority of aggressive prostate cancer and differential expression may have utility as a biomarker for disease recurrence.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4035.