Health Policy for Prostate Cancer Early Detection in the European Union and the Impact of Opportunistic Screening: PRAISE-U Consortium

With the new policy recommendation in 2022 to explore the possibilities of screening for prostate cancer by the European Commission, the landscape for prostate cancer early detection is evolving. In line with this recommendation, the PRAISE-U project aims to evaluate the early detection and diagnosis of prostate cancer through customised and risk-based screening programmes, with the goal to align protocols across European Union member states. This systematic review is part of the PRAISE-U project, with the goal to review the policy, medical guideline recommendations, and the current level of opportunistic screening presented in the scientific literature on prostate cancer early detection from 2016 to 2023 in European Union member states. An extensive literature search was performed on 1 June 2023 in a large number of databases, including Embase.com, Medline (Ovid), Web of Science Core Collection, Google Scholar, and Policy Commons. We identified 318 articles (qualitative, quantitative, and reviews), of which 41 were included in the full-text screening. Seventeen articles were ultimately identified as eligible for inclusion. The included articles revealed significant variations towards PSA-based early detection policies for prostate cancer in nine European countries. Despite official recommendations, opportunistic screening was prevalent across all nine countries regardless of recommendations for or against PSA-based early detection. This systematic review suggests that the current early detection policies are not fit for purpose. High levels of opportunistic screening and overdiagnosis persist, prompting policy recommendations for standardised guidelines, informed decision making, and increased awareness to improve efficiency and effectiveness in early detection.

Navigating through the Controversies and Emerging Paradigms in Early Detection of Prostate Cancer: Bridging the Gap from Classic RCTs to Modern Population-Based Pilot Programs

Over the last three decades, the European Randomized Study of Screening for Prostate Cancer (ERSPC) and the US-based Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening have steered the conversation around the early detection of prostate cancer. These two randomized trials assessed the effect of screening on prostate cancer disease-specific mortality. Elevated PSA levels were followed by a systematic sextant prostate biopsy. Standard repeat testing intervals were applied. After controversies from 2009 to 2016 due to contradicting results of the two trials, the results aligned in 2016 and showed that early PSA detection reduces prostate cancer-specific mortality. However, overdiagnosis rates of up to 50% were reported, and this sparked an intense debate on harms and benefits for almost 20 years. The balance between harms and benefits is highly debated and has initiated further research to investigate new ways of early detection. In the meantime, the knowledge and tools for the diagnostic algorithm improved. This is a continuously ongoing effort which focuses on individual risk-based screening algorithms that preserve the benefits of the purely PSA-based screening algorithms, while reducing the side effects. An important push towards investigating new techniques for early detection came from the European Commission on the 20th of September 2022. The European Commission published its updated recommendation to investigate prostate, lung, and gastric cancer early detection programs. This opened a new window of opportunity to move away from the trial setting to population-based early detection settings. With this review, we aim to review 30 years of historical evidence of prostate cancer screening, which led to the initiation of the 'The Prostate Cancer Awareness and Initiative for Screening in the European Union' (PRAISE-U) project, which aims to encourage the early detection and diagnosis of PCa through customized and risk-based screening programs.

NeuroSAFE in radical prostatectomy increases the rate of nerve-sparing surgery without affecting oncological outcome

OBJECTIVES

To investigate the impact of intra-operative neurovascular structure-adjacent frozen-section examination (NeuroSAFE) on the rate of nerve-sparing surgery (NSS) and oncological outcome in a large radical prostatectomy (RP) cohort.

PATIENTS AND METHODS

Between January 2016 and December 2020, 1756 prostate cancer patients underwent robot-assisted RP, of whom 959 (55%) underwent this with NeuroSAFE and 797 (45%) without (control cohort). In cases where NeuroSAFE showed tumour in the margin, a secondary resection was performed. The effect of NeuroSAFE on NSS and positive surgical margin (PSM) status was analysed using logistic regression. Cox regression was used to identify predictors of biochemical recurrence-free survival (BCRFS).

RESULTS AND LIMITATIONS

Patients in the NeuroSAFE cohort had a higher tumour grade (P < 0.001) and clinical stage (P < 0.001) than those in the control cohort. NeuroSAFE enabled more frequent NSS for both pT2 (93% vs 76%; P < 0.001) and pT3 disease (83% vs 55%; P < 0.001). In adjusted analysis, NeuroSAFE resulted in more frequent unilateral (odds ratio [OR] 3.90, 95% confidence interval (CI) 2.90-5.30; P < 0.001) and bilateral (OR 5.22, 95% CI 3.90-6.98; P < 0.001) NSS. While the PSM rate decreased from 51% to 42% in patients with pT3 stage disease (P = 0.031), NeuroSAFE was not an independent predictor of PSM status (OR 0.85, 95% CI 0.68-1.06; P = 0.2) in the entire cohort. Patients who underwent NeuroSAFE had better BCRFS compared to the control cohort (hazard ratio 0.62, 95% CI 0.45-0.84; P = 0.002). This study is limited by its comparison with a historical cohort and lack of functional outcomes.

CONCLUSIONS

NeuroSAFE enables more unilateral and bilateral NSS without negatively affecting surgical margin status and biochemical recurrence. This validation study provides a comprehensive overview of the implementation, evaluation and intra-operative decision making associated with NeuroSAFE in clinical practice.

Active Surveillance for Men Younger than 60 Years or with Intermediate-risk Localized Prostate Cancer. Descriptive Analyses of Clinical Practice in the Movember GAP3 Initiative

Background

Active surveillance (AS) is a management option for men diagnosed with low-risk prostate cancer. Opinions differ on whether it is safe to include young men (≤60 yr) or men with intermediate-risk disease.

Objective

To assess whether reasons for discontinuation, treatment choice after AS, and adverse pathology at radical prostatectomy (RP; N1, or ≥GG3, or ≥pT3) differ for men ≤60 yr or those with European Association of Urology (EAU) intermediate-risk disease from those for men >60 yr or those with EAU low-risk disease.

Design setting and participants

We analyzed data from 5411 men ≤60 yr and 14 959 men >60 yr, 14 064 men with low-risk cancer, and 2441 men with intermediate-risk cancer, originating from the GAP3 database (21 169 patients/27 cohorts worldwide).

Outcome measurements and statistical analysis

Cumulative incidence curves were used to estimate the rates of AS discontinuation and treatment choice.

Results and limitations

The probability of discontinuation of AS due to disease progression at 5 yr was similar for men aged ≤60 yr (22%) and those >60 yr (25%), as well as those of any age with low-risk disease (24%) versus those with intermediate-risk disease (24%). Men with intermediate-risk disease are more prone to discontinue AS without evidence of progression than men with low-risk disease (at 1/5 yr: 5.9%/14.2% vs 2.0%/8.8%). Adverse pathology at RP was observed in 32% of men ≤60 yr compared with 36% of men >60 yr (p = 0.029), and in 34% with low-risk disease compared with 40% with intermediate-risk disease (p = 0.048).

Conclusions

Our descriptive analysis of AS practices worldwide showed that the risk of progression during AS is similar across the age and risk groups studied. The proportion of adverse pathology was higher among men >60 yr than among men ≤60 yr. These results suggest that men ≤60 yr and those with EAU intermediate-risk disease should not be excluded from opting for AS as initial management.

Patient summary

Data from 27 international centers reflecting daily clinical practice suggest that younger men or men with intermediate-risk prostate cancer do not hold greater risk for disease progression during active surveillance.

Comparison of outcomes of different biopsy schedules among men on active surveillance for prostate cancer: An analysis of the G.A.P.3 global consortium database

BACKGROUND

The optimal interval for repeat biopsy during active surveillance (AS) for prostate cancer is yet to be defined. This study examined whether risk of upgrading (to grade group ≥ 2) or risk of converting to treatment varied according to intensity of repeat biopsy using data from the GAP3 consortium's global AS database.

MATERIALS AND METHODS

Intensity of surveillance biopsy schedules was categorized according to centers' protocols: (a) Prostate Cancer Research International Active Surveillance project (PRIAS) protocols with biopsies at years 1, 4, and 7 (10 centers; 7532 men); (b) biennial biopsies, that is, every other year (8 centers; 4365 men); and (c) annual biopsy schedules (4 centers; 1602 men). Multivariable Cox regression was used to compare outcomes according to biopsy intensity.

RESULTS

Out of the 13,508 eligible participants, 56% were managed according to PRIAS protocols (biopsies at years 1, 4, and 7), 32% via biennial biopsy, and 12% via annual biopsy. After adjusting for baseline characteristics, risk of converting to treatment was greater for those on annual compared with PRIAS biopsy schedules (hazard ratio [HR] = 1.66; 95% confidence interval [CI] = 1.51-1.83; p < 0.001), while risk of upgrading did not differ (HR = 0.96; 95% CI = 0.84-1.10).

CONCLUSION

Results suggest more frequent biopsy schedules may deter some men from continuing AS despite no evidence of grade progression.

Prostate Cancer Patients Under Active Surveillance with a Suspicious Magnetic Resonance Imaging Finding Are at Increased Risk of Needing Treatment: Results of the Movember Foundation's Global Action Plan Prostate Cancer Active Surveillance (GAP3) Consortium

BACKGROUND

The inclusion criterion for active surveillance (AS) is low- or intermediate-risk prostate cancer. The predictive value of the presence of a suspicious lesion at magnetic resonance imaging (MRI) at the time of inclusion is insufficiently known.

OBJECTIVE

To evaluate the percentage of patients needing active treatment stratified by the presence or absence of a suspicious lesion at baseline MRI.

DESIGN SETTING AND PARTICIPANTS

A retrospective analysis of the data from the multicentric AS GAP3 Consortium database was conducted. The inclusion criteria were men with grade group (GG) 1 or GG 2 prostate cancer combined with prostate-specific antigen <20 ng/ml. We selected a subgroup of patients who had MRI at baseline and for whom MRI results and targeted biopsies were used for AS eligibility. Suspicious MRI was defined as an MRI lesion with Prostate Imaging Reporting and Data System (PI-RADS)/Likert ≥3 and for which targeted biopsies did not exclude the patient for AS.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was treatment free survival (FS). The secondary outcomes were histological GG progression FS and continuation of AS (discontinuation FS).

RESULTS AND LIMITATIONS

The study cohort included 2119 patients (1035 men with nonsuspicious MRI and 1084 with suspicious MRI) with a median follow-up of 23 (12-43) mo. For the whole cohort, 3-yr treatment FS was 71% (95% confidence interval [CI]: 69-74). For nonsuspicious MRI and suspicious MRI groups, 3-yr treatment FS rates were, respectively, 80% (95% CI: 77-83) and 63% (95% CI: 59-66). Active treatment (hazard ratio [HR] = 2.0, p < 0.001), grade progression (HR = 1.9, p < 0.001), and discontinuation of AS (HR = 1.7, p < 0.001) were significantly higher in the suspicious MRI group than in the nonsuspicious MRI group.

CONCLUSIONS

The risks of switching to treatment, histological progression, and AS discontinuation are higher in cases of suspicious MRI at inclusion.

PATIENT SUMMARY

Among men with low- or intermediate-risk prostate cancer who choose active surveillance, those with suspicious magnetic resonance imaging (MRI) at the time of inclusion in active surveillance are more likely to show switch to treatment than men with nonsuspicious MRI.

Comparison of Characteristics, Follow-up and Outcomes of Active Surveillance for Prostate Cancer According to Ethnicity in the GAP3 Global Consortium Database

BACKGROUND

Studies of active surveillance (AS) for prostate cancer (PCa) have focussed predominantly on Caucasian populations. Little is known about the experience of Asian men, while suitability for men of African descent has been questioned.

OBJECTIVE

To compare baseline characteristics, follow-up, and outcomes for men on AS for PCa, according to ethnicity.

DESIGN SETTING AND PARTICIPANTS

The study cohort included 13 centres from the GAP3 consortium that record ethnicity (categorised broadly as Caucasian/white, African/Afro-Caribbean/black, Asian, mixed/other, and unknown). Men with biopsy grade group >2, prostate-specific antigen (PSA) >20 ng/ml, T stage ≥cT3, or age >80 yr were excluded.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Clinical characteristics, follow-up schedules, outcome status, and reasons for discontinuation were compared across ethnic groups. Risk of upgrading, potential disease progression (grade group ≥3 or T stage ≥3), suspicious indications (any upgrading, number of positive cores >3, T stage ≥cT3, PSA >20 ng/ml, or PSA density >0.2 ng/ml/cc²), and conversion to treatment were assessed using mixed-effect regression models.

RESULTS AND LIMITATIONS

The eligible cohort (n = 9158) comprised 83% Caucasian men, 6% men of African descent, 5% Asian men, 2% men of mixed/other ethnicity, and 4% men of unknown ethnicity. Risks of suspicious indicators (hazard ratio = 1.27; 95% confidence interval [CI] 1.12-1.45), upgrading (odds ratio [OR] = 1.40; 95% CI 1.14-1.71), and potential progression (OR = 1.46; 95% CI 1.06-2.01) were higher among African/black than among Caucasian/white men. Risk of transitioning to treatment did not differ by ethnicity. More Asian than Caucasian men converted without progression (42% vs 26%, p < 0.001). Heterogeneity in surveillance protocols and racial makeup limit interpretation.

CONCLUSIONS

This multinational study found differences in the risk of disease progression and transitioning to treatment without signs of progression between ethnic groups. Further research is required to determine whether differences are due to biology, sociocultural factors, and/or clinical practice.

PATIENT SUMMARY

This international study compared prostate cancer active surveillance outcomes by ethnicity. Risks of upgrading and disease progression were higher among African than among Caucasian men. Transitioning to treatment without progression was highest among Asian men. Understanding of these differences requires further investigation.

Improving the prediction of biochemical recurrence after radical prostatectomy with the addition of detailed pathology of the positive surgical margin and cribriform growth

The risk on biochemical recurrence (BCR) after radical prostatectomy (RP) is usually estimated using PSA and pathological stage and grading including the presence of positive surgical margins (PSM). Objective was to investigate whether the presence of cribriform growth in the primary tumor, Grade Group (GG) at the PSM, and length of the PSM have added value in the prognostication. We analyzed data of 835 patients initially treated with RP between 2000 and 2017. Cox regression models were developed to compare the baseline model (PSA, pT-stage, pN-stage, GG at RP, and presence of PSM) with an extended model (adding the presence of cribriform growth, length and GG at the PSM) using the likelihood ratio test. Discrimination was assessed at internal validation by the time-dependent area under the receiver operating characteristic curve (AUC) at 3- and 5-year. A total of 224 men experienced BCR. Median follow-up for men without BCR was 50.4 months (interquartile range, IQR 11.9-95.5). The extended model had a significant better fit, χ²(4) = 31.0, p < 0.001 than the baseline model. The AUC of the 3- and 5-year extended model was 0.85 (95% CI 0.81-0.88) compared to 0.83 (95% CI 0.79-0.87) for the baseline model. Importantly, the presence of cribriform growth in the primary tumor, and GG ≥ 2 at PSM were associated with a higher risk on BCR. In conclusion, the addition of pathological variables improved the prediction of the risk on BCR after RP slightly. However, the clinical implications of this model are important.

Using the Movember Foundation's GAP3 cohort to measure the effect of active surveillance on patient-reported urinary and sexual function-a retrospective study in low-risk prostate cancer patients

BACKGROUND

Active surveillance (AS) for low-risk prostate cancer (PCa) is intended to overcome potential side-effects of definitive treatment. Frequent prostate biopsies during AS may, however, impact erectile (EF) and urinary function (UF). The objective of this study was to test the influence of prostate biopsies on patient-reported EF and UF using multicenter data from the largest to-date AS-database.

METHODS

In this retrospective study, data analyses were performed using the Movember GAP3 database (v3.2), containing data from 21,169 AS participants from 27 AS-cohorts worldwide. Participants were included in the study if they had at least one follow-up prostate biopsy and completed at least one patient reported outcome measure (PROM) related to EF [Sexual Health Inventory for Men (SHIM)/five item International Index of Erectile Function (IIEF-5)] or UF [International Prostate Symptom Score (IPSS)] during follow-up. The longitudinal effect of the number of biopsies on either SHIM/IIEF-5 or IPSS were analyzed using linear mixed models to adjust for clustering at patient-level. Analyses were stratified by center; covariates included age and Gleason Grade group at diagnosis, and time on AS.

RESULTS

A total of 696 participants completed the SHIM/IIEF-5 3,175 times, with a median follow-up of 36 months [interquartile range (IQR) 20-55 months]. A total of 845 participants completed the IPSS 4,061 times, with a median follow-up of 35 months (IQR 19-56 months). The intraclass correlation (ICC) was 0.74 for the SHIM/IIEF-5 and 0.68 for the IPSS, indicating substantial differences between participants' PROMs. Limited heterogeneity between cohorts in the estimated effect of the number of biopsies on either PROM were observed. A significant association was observed between the number of biopsies and the SHIM/IIEF-5 score, but not for the IPSS score. Every biopsy was associated with a decrease in the SHIM/IIEF-5 score of an average 0.67 (95% CI, 0.47-0.88) points.

CONCLUSIONS

Repeated prostate biopsy as part of an AS protocol for men with low-risk PCa does not have a significant association with self-reported UF but does impact self-reported sexual function. Further research is, however, needed to understand whether the effect on sexual function implies a negative clinical impact on their quality of life and is meaningful from a patient's perspective. In the meantime, clinicians and patients should anticipate a potential decline in erectile function and hence consider incorporating the risk of this harm into their discussion about opting for AS and also when deciding on the stringency of follow-up biopsy schedules with long-term AS.

A first step towards a global nomogram to predict disease progression for men on active surveillance

BACKGROUND

Signs of disease progression (28%) and conversion to active treatment without evidence of disease progression (13%) are the main reasons for discontinuation of active surveillance (AS) in men with localised prostate cancer (PCa). We aimed to develop a nomogram to predict disease progression in these patients.

METHODS

As a first step in the development of a nomogram, using data from Movembers' GAP3 Consortium (n=14,380), we assessed heterogeneity between centres in terms of risk of disease progression. We started with assessment of baseline hazards for disease progression based on grouping of centres according to follow-up protocols [high: yearly; intermediate: ~2 yearly; and low: at year 1, 4 & 7 (i.e., PRIAS)]. We conducted cause-specific random effect Cox proportional hazards regression to estimate risk of disease progression by centre in each group.

RESULTS

Disease progression rates varied substantially between centres [median hazard ratio (MHR): 2.5]. After adjustment for various clinical factors (age, year of diagnosis, Gleason grade group, number of positive cores and PSA), substantial heterogeneity in disease progression remained between centres.

CONCLUSIONS

When combining worldwide data on AS, we noted unexplained differences of disease progression rate even after adjustment for various clinical factors. This suggests that when developing a global nomogram, local adjustments for differences in risk of disease progression and competing outcomes such as conversion to active treatment need to be considered.

Clinical outcome comparison of Grade Group 1 and Grade Group 2 prostate cancer with and without cribriform architecture at the time of radical prostatectomy

Aims

Invasive cribriform and intraductal carcinoma are associated with aggressive disease in Grade Group 2 (GG2) prostate cancer patients. However, the characteristics and clinical outcome of patients with GG2 prostate cancer without cribriform architecture (GG2−) as compared with those with Grade Group 1 (GG1) prostate cancer are unknown. The aim of this study was to investigate the clinical and pathological characteristics of GG1 and GG2− prostate cancer in radical prostatectomy specimens.

Methods and results

We reviewed 835 radical prostatectomy specimens for Grade Group, pT stage, surgical margin status, and the presence of cribriform architecture. Biochemical recurrence‐free survival and metastasis were used as clinical outcomes. GG1 prostate cancer was seen in 207 patients, and GG2 prostate cancer was seen in 420 patients, of whom 228 (54%) showed cribriform architecture (GG2+) and 192 (46%) did not. GG2− patients had higher prostate‐specific antigen levels (9.4 ng/ml versus 7.0 ng/ml; P < 0.001), more often had extraprostatic extension (36% versus 11%; P < 0.001) and had more positive surgical margins (27% versus 17%; P = 0.01) than GG1 patients. GG2− patients had shorter biochemical recurrence‐free survival (hazard ratio 2.7, 95% confidence interval 1.4–4.9; P = 0.002) than GG1 patients. Lymph node and distant metastasis were observed neither in GG2− nor in GG1 patients, but occurred in 22 of 228 (10%) GG2+ patients.

Conclusion

In conclusion, patients with GG2− prostate cancer at radical prostatectomy have more advanced disease and shorter biochemical recurrence‐free survival than those with GG1 prostate cancer, but both groups have a very low risk of developing metastasis.

Cribriform architecture in radical prostatectomies predicts oncological outcome in Gleason score 8 prostate cancer patients

The Gleason score is an important parameter for clinical outcome in prostate cancer patients. Gleason score 8 is a heterogeneous disease including Gleason score 3 + 5, 4 + 4, and 5 + 3 tumors, and encompasses a broad range of tumor growth patterns. Our objective was to characterize individual growth patterns and identify prognostic parameters in Gleason score 8 prostate cancer patients. We reviewed 1064 radical prostatectomy specimens, recorded individual Gleason 4 and 5 growth patterns as well as presence of intraductal carcinoma, and evaluated biochemical recurrence- and metastasis-free survival. Gleason score 8 disease was identified in 140 (13%) patients, of whom 76 (54%) had Gleason score 3 + 5, 46 (33%) 4 + 4, and 18 (13%) 5 + 3 disease. Invasive cribriform and/or intraductal carcinoma (n = 87, 62%) was observed more frequently in Gleason score 4 + 4 (93%) than 3 + 5 (47%; P < 0.001) and 5 + 3 (44%; P < 0.001) patients. Gleason pattern 5 was present in 110 (79%) men: as single cells and/or cords in 99 (90%) and solid fields in 32 (29%) cases. Solid field pattern 5 coexisted with cribriform architecture (23/32, 72%) more frequently than nonsolid pattern 5 cases (36/78, 46%, P = 0.02). In multivariable analysis including age, prostate-specific antigen, pT-stage, surgical margin status, and lymph node metastases, presence of cribriform architecture was an independent parameter for biochemical recurrence-free (hazard ratio (HR) 2.0, 95% confidence interval (CI) 1.0-3.7; P = 0.04) and metastasis-free (HR 3.5, 95% CI 1.0-12.3; P = 0.05) survival. In conclusion, invasive cribriform and/or intraductal carcinoma occurs more frequently in Gleason score 4 + 4 prostate cancer patients than in Gleason score 3 + 5 and 5 + 3, and is an independent parameter for biochemical recurrence and metastasis. Therefore, cribriform architecture has added value in risk stratification of Gleason score 8 prostate cancer patients.

Intraoperative assessment and reporting of radical prostatectomy specimens to guide nerve-sparing surgery in prostate cancer patients (NeuroSAFE)

Aims

Radical prostatectomy for prostate cancer is frequently complicated by urinary incontinence and erectile dysfunction. Nerve‐sparing surgery reduces the risk of postoperative complications and can be optimised by the use of intraoperative frozen sections of the adjacent neurovascular structure (NeuroSAFE). The aims of this study were to evaluate the pathological outcomes of the NeuroSAFE technique and to develop a comprehensive algorithm for intraoperative clinical decision‐making.

Methods and results

Between September 2018 and May 2019, 491 NeuroSAFE procedures were performed in 258 patients undergoing radical prostatectomy; 74 of 491 (15.1%) NeuroSAFE specimens had positive surgical margins. As compared with the corresponding paraffin sections, NeuroSAFE had a positive predictive value and negative predictive value of 85.1% and 95.4%, respectively. In 72.2% of secondary neurovascular bundle resections prompted by a NeuroSAFE positive surgical margin, no tumour was present. These cases more often had a positive surgical margin of ≤1 mm (48.7% versus 20.0%; P = 0.001) and only one positive slide (69.2% versus 33.3%; P = 0.008). None of the nine patients with Gleason pattern 3 at the surgical margin, a positive surgical margin length of ≤1 mm and one positive slide had tumour in the secondary resection.

Conclusions

This study provides a systematic reporting template for pathological intraoperative NeuroSAFE evaluation, supporting intraoperative clinical decision‐making and comparison between prostate cancer operation centres.

TP53 Mutations in Serum Circulating Cell-Free Tumor DNA As Longitudinal Biomarker for High-Grade Serous Ovarian Cancer

The aim of this study was to determine an optimal workflow to detect TP53 mutations in baseline and longitudinal serum cell free DNA (cfDNA) from high-grade serous ovarian carcinomas (HGSOC) patients and to define whether TP53 mutations are suitable as biomarker for disease. TP53 was investigated in tissue and archived serum from 20 HGSOC patients by a next-generation sequencing (NGS) workflow alone or combined with digital PCR (dPCR). AmpliSeq™-focused NGS panels and customized dPCR assays were used for tissue DNA and longitudinal cfDNAs, and Oncomine NGS panel with molecular barcoding was used for baseline cfDNAs. TP53 missense mutations were observed in 17 tissue specimens and in baseline cfDNA for 4/8 patients by AmpliSeq, 6/9 patients by Oncomine, and 4/6 patients by dPCR. Mutations in cfDNA were detected in 4/6 patients with residual disease and 3/4 patients with disease progression within six months, compared to 5/11 patients with no residual disease and 6/13 patients with progression after six months. Finally, mutations were detected at progression in 5/6 patients, but not during chemotherapy. NGS with molecular barcoding and dPCR were most optimal workflows to detect TP53 mutations in baseline and longitudinal serum cfDNA, respectively. TP53 mutations were undetectable in cfDNA during treatment but re-appeared at disease progression, illustrating its promise as a biomarker for disease monitoring.

Adherence to Active Surveillance Protocols for Low-risk Prostate Cancer: Results of the Movember Foundation's Global Action Plan Prostate Cancer Active Surveillance Initiative

BACKGROUND

Active surveillance (AS) enrolment criteria and follow-up schedules for low-risk prostate cancer vary between institutions. However, uncertainty remains about adherence to these protocols.

OBJECTIVE

To determine adherence to institution-specific AS inclusion criteria and follow-up schedules within the Movember Foundation's Global Action Plan Prostate Cancer Active Surveillance (GAP3) initiative.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively assessed the data of 15 101 patients from 25 established AS cohorts worldwide between 2014 and 2016.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Adherence to individual AS inclusion criteria was rated on a five-point Likert scale ranging from poor to excellent. Nonadherence to follow-up schedules was defined as absence of repeat biopsy 1 yr after the scheduled date. Cohorts were pooled into annual and Prostate Cancer Research International: Active Surveillance (PRIAS)-based biopsy schedules, and a generalised linear mixed model was constructed to test for nonadherence.

RESULTS AND LIMITATIONS

Serum prostate-specific antigen (PSA) inclusion criteria were followed in 92%, Gleason score (GS) criteria were followed in 97%, and the number of positive biopsy cores was followed in 94% of men. Both age and tumour stage (T stage) criteria had 99% adherence overall. Pooled nonadherence rates increased over time-8%, 16%, and 34% for annual schedules and 11%, 30%, and 29% for PRIAS-based schedules at 1, 4, and 7 yr, respectively-and did not differ between biopsy schedules. A limitation is that our results do not consider the use of multiparametric magnetic resonance imaging.

CONCLUSIONS

In on-going development of evidence-based AS protocols, variable adherence to PSA and GS inclusion criteria should be considered. Repeat biopsy adherence reduces with increased duration of surveillance, independent of biopsy frequency. This emphasises the importance of risk stratification at the commencement of AS.

PATIENT SUMMARY

We studied adherence to active surveillance protocols for prostate cancer worldwide. We found that inclusion criteria were generally followed well, but adherence to repeat biopsy reduced with time. This should be considered when optimising future active surveillance protocols.

Concordance of cribriform architecture in matched prostate cancer biopsy and radical prostatectomy specimens

Aims

Invasive cribriform and/or intraductal carcinoma have been identified as independent adverse parameters for prostate cancer outcome. Little is known on biopsy undersampling of cribriform architecture. Our aim was to determine the extent of cribriform architecture undersampling and to find predictive factors for identifying false cribriform‐negative cases.

Methods and results

We reviewed 186 matched prostate biopsies and radical prostatectomy specimens. Of 97 biopsy grade group 2 (Gleason score 3 + 4 = 7) patients, 22 (23%) had true cribriform‐negative (TN), 39 (40%) false‐negative (FN) and 36 (37%) true‐positive (TP) biopsies. Patients with FN biopsies had higher, although not statistically significant (P = 0.06), median PSA levels than patients with TP biopsies (12 versus 8 ng/ml). A PI‐RADS 5 lesion was present in nine of 16 (54%) FN and three of 11 (27%) TN biopsies (P = 0.05). Positive biopsy rate (P = 0.47), percentage Gleason pattern 4 (P = 0.55) and glomeruloid architecture (P = 1.0) were not different. Logistic regression identified PSA as an independent predictor (odds ratio = 3.5; 95% confidence interval = 1.2–9.4, P = 0.02) for cribriform architecture on radical prostatectomy, but not PI‐RADS score. The FN rate for large cribriform architecture at radical prostatectomy was 27%, which was lower than for any cribriform architecture (P = 0.01). During follow‐up (median 27 months), biochemical recurrence‐free survival of patients with TP biopsies was significantly shorter than that of those with FN biopsies (P = 0.03).

Conclusion

In conclusion, 40% of grade group 2 prostate cancer biopsies were FN for cribriform architecture. These patients had higher PSA levels and more frequent PI‐RADS score 5 lesions than men with TN biopsies.

Consistent Biopsy Quality and Gleason Grading Within the Global Active Surveillance Global Action Plan 3 Initiative: A Prerequisite for Future Studies

Within the Movember Foundation's Global Action Plan Prostate Cancer Active Surveillance (GAP3) initiative, 25 centers across the globe collaborate to standardize active surveillance (AS) protocols for men with low-risk prostate cancer (PCa). A centralized PCa AS database, comprising data of more than 15000 patients worldwide, was created. Comparability of the histopathology between the different cohorts was assessed by a centralized pathology review of 445 biopsies from 15 GAP3 centers. Grade group 1 (Gleason score 6) in 85% and grade group ≥2 (Gleason score ≥7) in 15% showed 89% concordance at review with moderate agreement (κ=0.56). Average biopsy core length was similar among the analyzed cohorts. Recently established highly adverse pathologies, including cribriform and/or intraductal carcinoma, were observed in 3.6% of the reviewed biopsies. In conclusion, the centralized pathology review of 445 biopsies revealed comparable histopathology among the 15 GAP3 centers with a low frequency of high-risk features. This enables further data analyses-without correction-toward uniform global AS guidelines for men with low-risk PCa. PATIENT SUMMARY: Movember Foundation's Global Action Plan Prostate Cancer Active Surveillance (GAP3) initiative combines data from 15000 men with low-risk prostate cancer (PCa) across the globe to standardize active surveillance protocols. Histopathology review confirmed that the histopathology was consistent with low-risk PCa in most men and comparable between different centers.

Reasons for Discontinuing Active Surveillance: Assessment of 21 Centres in 12 Countries in the Movember GAP3 Consortium

BACKGROUND

Careful assessment of the reasons for discontinuation of active surveillance (AS) is required for men with prostate cancer (PCa).

OBJECTIVE

Using Movember's Global Action Plan Prostate Cancer Active Surveillance initiative (GAP3) database, we report on reasons for AS discontinuation.

DESIGN, SETTING, AND PARTICIPANTS

We compared data from 10296 men on AS from 21 centres across 12 countries.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cumulative incidence methods were used to estimate the cumulative incidence rates of AS discontinuation.

RESULTS AND LIMITATIONS

During 5-yr follow-up, 27.5% (95% confidence interval [CI]: 26.4-28.6%) men showed signs of disease progression, 12.8% (95% CI: 12.0-13.6%) converted to active treatment without evidence of progression, 1.7% (95% CI: 1.5-2.0%) continued to watchful waiting, and 1.7% (95% CI: 1.4-2.1%) died from other causes. Of the 7049 men who remained on AS, 2339 had follow-up for >5yr, 4561 had follow-up for <5yr, and 149 were lost to follow-up. Cumulative incidence of progression was 27.5% (95% CI: 26.4-28.6%) at 5yr and 38.2% (95% CI: 36.7-39.9%) at 10yr. A limitation is that not all centres were included due to limited information on the reason for discontinuation and limited follow-up.

CONCLUSIONS

Our descriptive analyses of current AS practices worldwide showed that 43.6% of men drop out of AS during 5-yr follow-up, mainly due to signs of disease progression. Improvements in selection tools for AS are thus needed to correctly allocate men with PCa to AS, which will also reduce discontinuation due to conversion to active treatment without evidence of disease progression.

PATIENT SUMMARY

Our assessment of a worldwide database of men with prostate cancer (PCa) on active surveillance (AS) shows that 43.6% drop out of AS within 5yr, mainly due to signs of disease progression. Better tools are needed to select and monitor men with PCa as part of AS.

Large cribriform growth pattern identifies ISUP grade 2 prostate cancer at high risk for recurrence and metastasis

Invasive cribriform and intraductal carcinoma are associated with adverse clinical outcome in patients with Gleason score 7 prostate cancer. It is yet unclear whether invasive cribriform and intraductal carcinoma of the prostate both have independent prognostic value, or whether field size of invasive cribriform carcinoma has impact on disease outcome. Our objective was to determine the prognostic impact of intraductal and invasive cribriform prostate cancer histological subtypes in radical prostatectomies. We reviewed 420 prostatectomy specimens with ISUP grade 2 prostate cancer, assessed the percentages of Gleason grade 4 and tertiary 5, and performed immunohistochemistry for basal cells to discriminate intraductal from invasive cribriform growth. Small and large invasive cribriform fields were distinguished based on a diameter of at least twice the size of adjacent pre-existent normal glands. Clinicopathological parameters and biochemical recurrence-free survival were used as endpoints. Cribriform architecture was observed in 228 (54.3%) men, 103 (24.5%) of whom had intraductal, 194 (46.2%) small invasive, and 34 (8.1%) large invasive cribriform growth. Large invasive cribriform architecture was associated with older age (P < 0.001), higher percentage Gleason grade 4 (P = 0.001), extraprostatic expansion (P < 0.001), and more frequent lymph node metastases (P = 0.002), when compared with small invasive cribriform and/or intraductal carcinoma. Univariate analysis identified PSA, pT-stage, surgical margin status, and intraductal and invasive cribriform growth as significant predictors for biochemical recurrence-free survival. In multivariable Cox regression analysis, pT-stage (hazard ratio = 1.64, 95% CI: 1.02-2.63, P = 0.04), positive surgical margins (hazard ratio = 3.28, 95% CI: 2.06-5.23, P < 0.001), and large cribriform growth (hazard ratio = 4.36, 95% CI: 2.08-9.17, P < 0.001) were independent predictors for biochemical recurrence-free survival, while intraductal carcinoma, small cribriform growth, and percentage of Gleason grade 4 were not. In conclusion, large cribriform fields represent an aggressive subpattern of invasive cribriform prostate cancer and are an independent predictive factor for biochemical recurrence-free survival in ISUP grade 2 prostate cancer patients.

Active surveillance for prostate cancer: a systematic review of contemporary worldwide practices

In the last decade, active surveillance (AS) has emerged as an acceptable choice for low-risk prostate cancer (PC), however there is discordance amongst large AS cohort studies with respect to entry and monitoring protocols. We systematically reviewed worldwide AS practices in studies reporting ≥5 years follow-up. We searched PubMed and Medline 2000-now and identified 13 AS cohorts. Three key areas were identified: (I) patient selection; (II) monitoring protocols; (III) triggers for intervention—(I) all studies defined clinically localised PC diagnosis as T2b disease or less and most agreed on prostate-specific antigen (PSA) threshold (<10 µg/L) and Gleason score threshold (3+3). Inconsistency was most notable regarding pathologic factors (e.g., number of positive cores); (II) all agreed on PSA surveillance as crucial for monitoring, and most agreed that confirmatory biopsy was required within 12 months of initiation. No consensus was reached on optimal timing of digital rectal examination (DRE), general health assessment or re-biopsy strategies thereafter; (III) there was no universal agreement for intervention triggers, although Gleason score, number or percentage of positive cancer cores, maximum cancer length (MCL) and PSA doubling time were used by several studies. Some also used imaging or re-biopsy. Despite consistent high progression-free/cancer-free survival and conversion-to-treatment rates, heterogeneity exists amongst these large AS cohorts. Combining existing evidence and gathering more long-term evidence [e.g., the Movember’s Global AS database or additional information on use of magnetic resonance imaging (MRI)] is needed to derive a broadly supported guideline to reduce variation in clinical practice.

APOBEC3G Expression Correlates with T-Cell Infiltration and Improved Clinical Outcomes in High-grade Serous Ovarian Carcinoma

PURPOSE

APOBEC3 DNA cytosine deaminase family members normally defend against viruses and transposons. However, deregulated APOBEC3 activity causes mutations in cancer. Because of broad expression profiles and varying mixtures of normal and cancer cells in tumors, including immune cell infiltration, it is difficult to determine where different APOBEC3s are expressed. Here, we ask whether correlations exist between APOBEC3 expression and T-cell infiltration in high-grade serous ovarian cancer (HGSOC), and assess whether these correlations have prognostic value.

EXPERIMENTAL DESIGN

Transcripts for APOBEC3G, APOBEC3B, and the T-cell markers, CD3D, CD4, CD8A, GZMB, PRF1, and RNF128 were quantified by RT-qPCR for a cohort of 354 HGSOC patients. Expression values were correlated with each other and clinical parameters. Two additional cohorts were used to extend HGSOC clinical results. Immunoimaging was used to colocalize APOBEC3G and the T-cell marker CD3. TCGA data extended expression analyses to additional cancer types.

RESULTS

A surprising positive correlation was found for expression of APOBEC3G and several T cell genes in HGSOC. Immunohistochemistry and immunofluorescent imaging showed protein colocalization in tumor-infiltrating T lymphocytes. High APOBEC3G expression correlated with improved outcomes in multiple HGSOC cohorts. TCGA data analyses revealed that expression of APOBEC3D and APOBEC3H also correlates with CD3D across multiple cancer types.

CONCLUSIONS

Our results identify APOBEC3G as a new candidate biomarker for tumor-infiltrating T lymphocytes and favorable prognoses for HGSOC. Our data also highlight the complexity of the tumor environment with respect to differential APOBEC family gene expression in both tumor and surrounding normal cell types. Clin Cancer Res; 22(18); 4746-55. ©2016 AACR.

Ovarian cancer cell line panel (OCCP): clinical importance of in vitro morphological subtypes

Epithelial ovarian cancer is a highly heterogeneous disease and remains the most lethal gynaecological malignancy in the Western world. Therapeutic approaches need to account for inter-patient and intra-tumoural heterogeneity and detailed characterization of in vitro models representing the different histological and molecular ovarian cancer subtypes is critical to enable reliable preclinical testing. There are approximately 100 publicly available ovarian cancer cell lines but their cellular and molecular characteristics are largely undescribed. We have characterized 39 ovarian cancer cell lines under uniform conditions for growth characteristics, mRNA/microRNA expression, exon sequencing, drug response for clinically-relevant therapeutics and collated all available information on the original clinical features and site of origin. We tested for statistical associations between the cellular and molecular features of the lines and clinical features. Of the 39 ovarian cancer cell lines, 14 were assigned as high-grade serous, four serous-type, one low-grade serous and 20 non-serous type. Three morphological subtypes: Epithelial (n = 21), Round (n = 7) and Spindle (n = 12) were identified that showed distinct biological and molecular characteristics, including overexpression of cell movement and migration-associated genes in the Spindle subtype. Comparison with the original clinical data showed association of the spindle-like tumours with metastasis, advanced stage, suboptimal debulking and poor prognosis. In addition, the expression profiles of Spindle, Round and Epithelial morphologies clustered with the previously described C1-stromal, C5-mesenchymal and C4 ovarian subtype expression profiles respectively. Comprehensive profiling of 39 ovarian cancer cell lines under controlled, uniform conditions demonstrates clinically relevant cellular and genomic characteristics. This data provides a rational basis for selecting models to develop specific treatment approaches for histological and molecular subtypes of ovarian cancer.

Abstract 949: miR-634 restores drug sensitivity in tumor cells derived from patients with terminal drug-resistant ovarian cancer

The development of drug resistance is still a major impediment for the successful treatment of cancer. This is particularly pressing in the case of advanced ovarian cancer, which has a 5-year survival rate of 30%. Ovarian cancer is treated with paclitaxel and platinum (e.g cisplatin or carboplatin) combination chemotherapy. Despite an initial high chemo-responsiveness, most ovarian cancer patients will relapse and ultimately die of drug-resistant disease. The molecular processes that contribute to resistance have been extensively studied, however, not much is known about the role of microRNAs (miRNAs), small non-coding RNAs that regulate gene expression.

We compared miRNA expression profiles of isogenic cisplatin sensitive and resistant cell line pairs. The only miRNA that was consistently downregulated in all three resistant cell lines was miR-634 (FDR&lt;1%). Overexpression of miR-634 in ovarian cancer cell lines gave rise to a minor, but reproducible, cell cycle block and reduced cellular viability by 20-50%. In addition, miR-634 transfection resensitized cisplatin-resistant ovarian cancer cell lines. We next investigated whether miR-634 overexpression could enhance therapy response in a more clinical setting. We isolated and cultured tumor cells from 7 patients that had become refractory to carboplatin-paclitaxel combination chemotherapy. We show that miR-634 overexpression causes a ∼two-fold decrease in IC50 for cisplatin and carboplatin treatment. In addition, a ∼1.3-fold decrease in doxorubicin sensitivity was observed upon miR-634 overexpression. Finally, overexpression of miR-634 resulted in downregulation of its predicted targets Cyclin D1 and GRB2, ERK2, RSK1 and RSK2, components of the Ras-MAPK pathway. The combined effect on these miR-634 targets may explain the effects on the cell cycle, cellular viability and response to chemotherapy.

Altogether, our findings suggest that miR-634 modulates important cancer relevant targets and that raising miR-634 levels can be a means to resensitize chemotherapy resistant ovarian tumors.

Citation Format: Marijn TM van Jaarsveld, Patricia F. van Kuijk, Antonius WM Boersma, Jozien Helleman, Wilfred F. van Ijcken, Ron HJ Mathijssen, Joris Pothof, Els MJJ Berns, Jaap Verweij, Erik AC Wiemer. miR-634 restores drug sensitivity in tumor cells derived from patients with terminal drug-resistant ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 949. doi:10.1158/1538-7445.AM2013-949

Abstract 4238: Unique ovarian cancer cell line panel: Molecular subtypes and therapy response

Epithelial ovarian cancer is the most lethal gynecological malignancy in the Western world. Up to 70% of the patients do not survive the first 5 years after diagnosis, mostly due to acquired chemotherapy resistance. With the goal to stratify a heterogeneous group of patients, recently, a number of studies have identified molecular subtypes within ovarian carcinomas. However, the relation with response to chemotherapeutics is unknown. An extensive model system in which the response to different chemotherapeutics can be related to molecular subtypes is therefore imperative to know how to individualize treatment based on these molecular subtypes. We have an (increasing) collection of so far 40 ovarian cancer cell lines. The large number and extensive characterization of the cell lines makes this a unique model. We have data of the growth and morphological properties, exon-based gene expression (22.000 genes), microRNA expression (400 miRNAs), mutation analysis (PIK3CA, RAF & RAS genes), microsatellite instability status (MSI) and response curves for eight chemotherapeutics used in first- and second-line treatment. Unsupervised absolute clustering using the most variable expressed genes and microRNAs revealed two even clusters of cell lines with significantly different characteristics. The cell lines in the first cluster compared to the second: -show more often a round and less often an epithelial morphology (cell lines with spindle morphology are divided over both clusters), -show more often no Epithelial Cell Adhesion Molecule (EpCAM) and high CD44 membrane expression -are highly proliferative -are more often PI3K/Ras mutated and MSI Interestingly, the cell lines within the first cluster are significantly more sensitive to six of the eight tested chemotherapeutics compared to the second cluster BRB class comparison analysis revealed that 287 genes were differentially expressed between the two clusters (permutation p&lt;0.01, FDR&lt;5%, 10.000 permutations). Pathway analysis of these genes revealed the significantly overrepresented canonical pathways and molecular & cellular functions including Interferon Signaling (p=0.007), Arachidonic Acid Metabolism (p=0.030) and Cell-To-Cell Signaling and Interaction (p&lt;0.03). We are currently identifying the published clinical molecular subtypes in our cell lines and relating it with response to treatment. This will give information on which of the commonly used therapeutics are expected to be most effective in the different molecular subtype. In the future, the response to targeted therapeutics can be tested in our cell line panel which may give additional information on how to treat each subtype. In conclusion, this large panel of extremely well characterized ovarian cancer cell lines is a unique model system that can be used in many future translational and functional studies and we are happy to collaborate (j.helleman@erasmusmc.nl).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4238. doi:1538-7445.AM2012-4238

Microarray-based oncogenic pathway profiling in advanced serous papillary ovarian carcinoma

INTRODUCTION

The identification of specific targets for treatment of ovarian cancer patients remains a challenge. The objective of this study is the analysis of oncogenic pathways in ovarian cancer and their relation with clinical outcome.

METHODOLOGY

A meta-analysis of 6 gene expression datasets was done for oncogenic pathway activation scores: AKT, β-Catenin, BRCA, E2F1, EGFR, ER, HER2, INFα, INFγ, MYC, p53, p63, PI3K, PR, RAS, SRC, STAT3, TNFα, and TGFβ and VEGF-A. Advanced serous papillary tumours from uniformly treated patients were selected (N = 464) to find differences independent from stage-, histology- and treatment biases. Survival and correlations with documented prognostic signatures (wound healing response signature WHR/genomic grade index GGI/invasiveness gene signature IGS) were analysed.

RESULTS

The GGI, WHR, IGS score were unexpectedly increased in chemosensitive versus chemoresistant patients. PR and RAS activation score were associated with survival outcome (p = 0.002;p = 0.004). Increased activations of β-Catenin (p = 0.0009), E2F1 (p = 0.005), PI3K (p = 0.003) and p63 (p = 0.05) were associated with more favourable clinical outcome and were consistently correlated with three prognostic gene signatures.

CONCLUSIONS

Oncogenic pathway profiling of advanced serous ovarian tumours revealed that increased β-Catenin, E2F1, p63, PI3K, PR and RAS-pathway activation scores were significantly associated with favourable clinical outcome. WHR, GGI and IGS scores were unexpectedly increased in chemosensitive tumours. Earlier studies have shown that WHR, GGI and IGS are strongly associated with proliferation and that high-proliferative ovarian tumours are more chemosensitive. These findings may indicate opposite confounding of prognostic versus predictive factors when studying biomarkers in epithelial ovarian cancer.

Abstract 411: Pathway analysis of gene-lists associated with platinum-based chemotherapy resistance in ovarian cancer: the big picture

Objective. Ovarian cancer is the leading cause of death from gynecological cancers in the Western world [1]. The overall 5-year survival is only 30% [2], which is for a significant part due to platinum-based chemotherapy resistance. In this study, we performed a pathway analysis on nine published gene-sets associated with platinum resistance in ovarian cancer, including a study by us. With this exploratory study, we aim to identify overlapping pathways associated with platinum-based chemotherapy resistance mechanisms in ovarian cancer.

Methods A Gene Ontology (GO) analysis and Ingenuity Pathway Analysis (IPA) was performed to determine which functional processes were differentially represented in the combined gene-lists of nine studies (457 genes) compared to all Unigene identifiers or the Ingenuity knowledge base.

Results. The GO and IPA analysis resulted in the generation of 23 gene networks, and showed that 13 GO processes (&gt;=2 times enriched), 71 canonical pathways (p&lt;0.05,), eight toxicity pathways (p&lt;.05) and 74 biological functions (p&lt;0.005) are significantly associated with the 9-study gene set.

Conclusion and recommendations. Several pathways identified have previously been shown to be associated with therapy resistance: these include ‘oxidative stress response mediated by Nrf2’, ‘TP53 signaling’ and ‘TGFbeta signaling’. The role of TGFbeta signalling as well as related miRNAs identified in the network analysis in epithelial-to-mesenchymal transition (EMT) and stemness as well as the possible relation with platin-based chemotherapy resistance is further discussed in detail.

We propose that future international cooperation should aim at a uniform pooled-analysis of the wealth of ovarian cancer array data already available. This will enhance the power of each separate ovarian cancer study and can lead to promising results.

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 411.

MicroRNAs in ovarian cancer biology and therapy resistance

Epithelial ovarian cancer is the most common cause of death from gynecological malignancies in the Western world. The overall 5-year survival is only 30% due to late diagnosis and development of resistance to chemotherapy. There is, therefore, a strong need for prognostic and predictive markers to help optimize and personalize treatment hence ameliorating the prognosis of ovarian cancer patients. Since 2006, an increasing number of studies have indicated an essential role for microRNAs in ovarian cancer tumorigenesis. In this review, we provide an overview of the microRNAs that have been associated with different aspects of ovarian cancer, such as tumor subtype, stage, histological grade, germline mutations in BRCA genes, prognosis and therapy resistance. We highlight the role of the let-7 and miR-200 families, two major microRNA families that are frequently dysregulated in ovarian cancer and have been associated with poor prognosis. Interestingly, both have been implicated in the regulation of the epithelial-to-mesenchymal transition, a cellular transition associated with tumor aggressiveness, tumor invasion and chemoresistance. Furthermore, we discuss several other microRNAs that have been associated with chemotherapy resistance, such as miR-214, miR-130a, miR-27a and miR-451. In the final section, we speculate on the possibilities of microRNA-based therapies and the use of microRNAs as diagnostic tools.

Differential transport of platinum compounds by the human organic cation transporter hOCT2 (hSLC22A2)

BACKGROUND

Solute carriers (SLCs), in particular organic cation transporters (OCTs), have been implicated in the cellular uptake of platinum-containing anticancer compounds. The activity of these carriers may determine the pharmacokinetics and the severity of side effects, including neuro- and nephrotoxicity of platinum-based chemotherapy. As decreased drug accumulation is a key mechanism of platinum resistance, SLCs may also contribute to the development of resistance. Here, we define the role of hSLC22A2 (OCT2) in the cellular uptake of platinum compounds.

EXPERIMENTAL APPROACH

Human embryonic kidney (HEK) 293 cells stably expressing the hSLC22A2 gene (HEK293/hSLC22A2) were used in platinum accumulation studies. Following a 2 h exposure to various platinum compounds (100 microM), intracellular platinum levels were determined by flameless atomic absorption spectrometry.

KEY RESULTS

HEK293/hSLC22A2 cells, compared with HEK293/Neo control cells, displayed significant increases in oxaliplatin (28.6-fold), Pt[DACH]Cl(2) (20.6-fold), ormaplatin (8.1-fold), tetraplatin (4.5-fold), transplatin (3.7-fold) and cisplatin (1.3-fold), but not carboplatin. SLC22A2-mediated transport could be inhibited by 1-methyl-4-phenylpyridinium. Furthermore, hSLC22A2-mediated oxaliplatin and cisplatin accumulation was time- and concentration-dependent, but non-saturable. Expression of hSLC22A2 in HEK293 cells resulted in enhanced sensitivity to oxaliplatin (12-fold) and cisplatin (1.8-fold). Although, hSLC22A2 mRNA expression was frequently found in ovarian cancer cell lines, its expression in clinical ovarian cancer specimens (n= 80) was low and did not correlate with the treatment outcome of platinum-based regimens.

CONCLUSIONS AND IMPLICATIONS

The hSLC22A2 drug transporter is a critical determinant in the uptake and cytotoxicity of various platinum compounds, particularly oxaliplatin.

Integrated genomics of chemotherapy resistant ovarian cancer: a role for extracellular matrix, TGFbeta and regulating microRNAs

Epithelial ovarian cancer is the sixth most common cancer in women worldwide and the most important cause of death from gynaecological cancers in the Western world. Our explorative pathway analysis on seven published gene-sets associated with platinum resistance in ovarian cancer reveals TP53 and transforming growth factor beta as key genes. Furthermore, the extracellular matrix was associated with chemotherapy resistance in ovarian cancer as well as endocrine resistance in breast cancer. Pathway analysis again revealed transforming growth factor beta as a key gene regulating extracellular matrix gene expression. A model is presented based on literature linking transforming growth factor beta, extracellular matrix, integrin signalling, epithelial to mesenchymal transition and regulating microRNAs with a (bivalent) role in chemotherapy response.

The VEGF pathway and the AKT/mTOR/p70S6K1 signalling pathway in human epithelial ovarian cancer

Vascular endothelial growth factor (VEGF)-A inhibitors exhibit unseen high responses and toxicity in recurrent epithelial ovarian cancer suggesting an important role for the VEGF/VEGFR pathway. We studied the correlation of VEGF signalling and AKT/mTOR signalling. Using a tissue microarray of clinical samples (N=86), tumour cell immunohistochemical staining of AKT/mTOR downstream targets, pS6 and p4E-BP1, together with tumour cell staining of VEGF-A and pVEGFR2 were semi-quantified. A correlation was found between the marker for VEGFR2 activation (pVEGFR2) and a downstream target of AKT/mTOR signalling (pS6) (R=0.29; P=0.002). Additional gene expression analysis in an independent cDNA microarray dataset (N=24) showed a negative correlation (R=−0.73, P<0.0001) between the RPS6 and the VEGFR2 gene, which is consistent as the gene expression and phosphorylation of S6 is inversely regulated. An activated tumour cell VEGFR2/AKT/mTOR pathway was associated with increased incidence of ascites (χ², P=0.002) and reduced overall survival of cisplatin–taxane-based patients with serous histology (N=32, log-rank test, P=0.04). These data propose that VEGF-A signalling acts on tumour cells as a stimulator of the AKT/mTOR pathway. Although VEGF-A inhibitors are classified as anti-angiogenic drugs, these data suggest that the working mechanism has an important additional modality of targeting the tumour cells directly.

Decreased expression of EZH2 is associated with ESR1 upregulation and response to anti-estrogens

Abstract #6127

Background: In prostate and breast cancer high levels of Enhancer of Zeste Homolog 2 (EZH2) are associated with tumor progression. EZH2, a histone H3 methyl transferase, is part of the polycomb complex. Together with histone deacetylases (HDACs) EZH2 regulates “genome wide” gene transcription silencing. The aims of this study are a) to correlate EZH2 expression with endocrine therapy response in patients with recurrent disease treated with first-line tamoxifen monotherapy and b) to determine the role of EZH2 in endocrine therapy response using in vitro cell line models.&#x2028; Material and Methods: EZH2 mRNA levels were measured with quantitative real-time PCR (qRT-PCR) in 297 retrospectively collected hormone receptor positive (HR+) primary breast tumor specimens of patients with recurrent disease who did respond (N=110) or were resistant (N=187) to first-line tamoxifen monotherapy. In vitro, EZH2 and estrogen receptor (ESR1) expression was downregulated with siRNAs in the human breast cancer cell line MCF7 and assessed for their sensitivity to the selective estrogen receptor degrader ICI164.384 after 96hrs treatment (N=3). To establish therapy response in vitro, cell number counts were determined. All p-values are two-sided and significant if P&lt;0.05.&#x2028; Results: In 297 HR+ breast tumors, EZH2 as continuous variable, associated significantly with poor response (OR= 0.67 [0.49-0.91]; P=0.001) and a shorter progression-free survival (PFS) (HR=1.28 [1.11-1.47], P&lt;0.001). In the multivariate model with traditional predictive factors, the tertile with highest EZH2 levels was independently related with response (OR= 0.50 [0.26-0.98]; P=0.045) and PFS (HR=1.82 [1.33-2.49], P&lt;0.001).&#x2028; In vitro, EZH2 downregulation in MCF7 with siRNAs showed a significant decrease in cell number compared to the mock silenced cell line (40%). Moreover, ICI treatment of EZH2 silenced MCF7 cells resulted in a 70% cell number decrease versus 23% decrease in the controls (P&lt;0.001). In addition, EZH2 downregulation is associated with a twofold upregulation with ESR1 (P&lt;0.001). Conversely, silencing of ESR1 in MCF7 resulted did not alter EZH2 levels but, as expected, increases HER2 protein levels.&#x2028; Conclusion: In primary breast tumors, high EZH2 mRNA levels are associated with poor outcomes after tamoxifen therapy. These results suggest that EZH2 may identify patients at risk for tamoxifen therapy failure. In vitro studies show that downregulation of EZH2 inhibits cell proliferation and on the other hand results in upregulation of ESR1 levels. The latter may explain the increased sensitivity to ICI164.384 of EZH2 silenced cells.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6127.

Association of an extracellular matrix gene cluster with breast cancer prognosis and endocrine therapy response

PURPOSE

We previously discovered an extracellular matrix (ECM) gene cluster associated with resistance to first-line tamoxifen therapy of patients with metastatic breast cancer. In this study, we determined whether the six individual ECM genes [collagen 1A1 (COL1A1), fibronectin 1 (FN1), lysyl oxidase (LOX), secreted protein acidic cysteine-rich (SPARC), tissue inhibitor of metalloproteinase 3 (TIMP3), and tenascin C (TNC)] were associated with treatment response, prognosis, or both.

EXPERIMENTAL DESIGN

In 1,286 primary breast tumors, mRNA expression (quantitative real-time PCR) was related to clinicopathologic factors and disease outcome in univariate and multivariate analysis including traditional factors.

RESULTS

TIMP3, FN1, LOX, and SPARC expression levels (continuous variables) were significantly associated with distant metastasis-free survival (MFS) in 680 lymph node-negative untreated patients (P<0.03). Using a calculated linear prognostic score, these patients were evenly divided into five prognostic groups with a significant difference in 10-year MFS of approximately 40% between the two extreme prognostic groups. Furthermore, high TNC expression as continuous variable was associated with (a) shorter MFS in 139 estrogen receptor-positive and lymph node-positive patients who received adjuvant tamoxifen therapy (hazard ratio, 1.53; P=0.001), and (b) no clinical benefit (odds ratio, 0.81; P=0.035) and shorter progression-free survival (hazard ratio, 1.19; P=0.002) in 240 patients in whom recurrence was treated with tamoxifen as first-line monotherapy. These results were also significant in multivariate analyses.

CONCLUSION

FN1, LOX, SPARC, and TIMP3 expression levels are associated with the prognosis of patients with breast cancers, whereas TNC is associated with resistance to tamoxifen therapy. Further validation and functional studies are necessary to determine the use of these ECM genes in decisions regarding treatment and whether they can serve as targets for therapy.

Downregulation of SIAH2, an ubiquitin E3 ligase, is associated with resistance to endocrine therapy in breast cancer

PURPOSE

In our microarray analysis we observed that Seven-in-Absentia Homolog 2 (SIAH2) levels were low in estrogen receptor (ER) positive breast tumors of patients resistant to first-line tamoxifen therapy. The aim of this study was to evaluate SIAH2 for its (a) predictive/prognostic value, and (b) functional role in endocrine therapy resistance.

PATIENTS AND METHODS

SIAH2 expression was measured with quantitative Real-Time-PCR (qRT-PCR) in 1205 primary breast tumor specimens and related to disease outcome. The functional role of SIAH2 was determined in human breast cancer cell lines ZR-75-1, ZR/HERc, and MCF7. Cell lines were treated with estrogen (E2), anti-estrogen ICI164.384 or epidermal growth factor (EGF). Moreover, MCF7 was treated with ICI164.384 after silencing SIAH2 expression.

RESULTS

SIAH2 was not prognostic in 603 lymph node negative patients who had not received adjuvant systemic therapy. In multivariate analysis of ER-positive tumors of 235 patients with recurrent disease, SIAH2 as continuous variable, significantly predicted first-line tamoxifen treatment failure (OR = 1.48; P = 0.05) and progression-free survival (PFS) (HR = 0.79; P = 0.007). Furthermore, in primary breast cancer patients treated with adjuvant tamoxifen, SIAH2 predicted metastasis-free survival (MFS) (HR = 0.73; P = 0.005). In vitro experiments showed that SIAH2 silencing in MCF7 cells resulted in resistance to ICI164.384-treatment when compared with mock silenced cells (P = 0.008). Interestingly, in ZR cells transfected with EGFR (ZR/HERc), SIAH2 expression was induced by E2 but downregulated by EGF.

CONCLUSION

In primary breast tumor specimens as well as in vitro low SIAH2 levels associated with resistance to endocrine therapy. Moreover, SIAH2 expression showed an opposite regulation by E2 and EGF.

Serum proteomic patterns for ovarian cancer monitoring

We set out to discover ovarian cancer biomarkers useful for monitoring progression during and after chemotherapy and possibly for diagnosis. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry was used to create serum protein profiles of ovarian cancer patients before chemotherapy or at progression (n = 51) (trial initiated by the Gynecological Cancer Cooperative Group of the European Organization for Research and Treatment of Cancer trial) that were compared with those of healthy individuals (n = 31). In addition, sera profiles from ovarian cancer patients after chemotherapy (n = 12) were compared with those of ovarian cancer patients at progression (n = 24). One of the discovered biomarkers was identified and subsequently confirmed and validated using enzyme-linked immunosorbent assay (ELISA). Eight primary (sens = 94%, spec = 97%, P < 0.0001) and seven progression tumor biomarkers (sens = 91%, spec = 97%, P < 0.0001) were discovered. In addition, we discovered eight potential progression monitoring biomarkers (sens = 75%, spec = 83%, P = 0.0008) of which one, a biomarker of 11.7 kd, was further identified as serum amyloid A1. Independent validation (ELISA) showed an elevated expression of this protein at relapse in four of the seven ovarian cancer patients tested. Combining the eight newly discovered progression monitoring biomarkers with CA125 resulted in a clear increase of the sensitivity (91-100%). These biomarkers, in combination with for instance CA125, should be validated in large ovarian cancer and control groups. The resulting multimarker assay could be suitable for disease monitoring during and after therapy and might also be useful for ovarian cancer screening.

Impaired cisplatin influx in an A2780 mutant cell line: Evidence for a putative, cis-configuration-specific, platinum influx transporter

The effectiveness of platinum drugs in the treatment of cancer is hindered by intrinsic and acquired resistance. The cause of clinical resistance to platinum compounds is still unknown. In an attempt to identify new cellular mechanisms of cisplatin resistance, a one-step cisplatin-selection procedure was used to generate resistant sublines of the platinum sensitive A2780 ovarian cancer cell line. In the present study we selected an A2780 subline, A2780-Pt, that has a significantly reduced ability to accumulate cisplatin (36% of the parent A2780 cell line) and consequently shows a clear cisplatin-resistant phenotype (resistance factor, i.e., RF: 8.6). The A2780-Pt cell line was specifically cross-resistant to carboplatin (RF: 12.0), tetraplatin (RF: 8.1) and oxaliplatin (RF: 6.1) which was associated with a reduced cellular platinum accumulation (50%, 54% and 58% of A2780, respectively). No cross-resistance was found for a variety of other anticancer agents. Further experiments to determine the cause of the platinum resistance of the A2780-Pt cell line revealed that: (1) impaired cellular platinum accumulation could not be attributed to aberrant expression of MRP2 (ABCC2), CTR1 (SLC31A1), ATP7A or ATP7B, (2) resistance was not associated with platinum inactivation by metallothionein and glutathione, (3) the platinum efflux rate was similar to that of A2780, (4) the defect in cellular accumulation and the resistance could be overcome by treatment with cisplatin nanocapsules, consistent with impaired influx, and (5) the defect in accumulation is specific for platinum compounds in the cis-configuration, since A2780-Pt cells did not show reduced accumulation of transplatin. This specificity suggests that not passive diffusion but an inward transporter is impaired in A2780-Pt. In conclusion, we generated an A2780 subline that showed a uniquely stable platinum resistance phenotype, which could theoretically be caused by an impaired inward transporter specific for cis-configurated platinum compounds.

Mismatch repair and treatment resistance in ovarian cancer

BACKGROUND

The treatment of ovarian cancer is hindered by intrinsic or acquired resistance to platinum-based chemotherapy. The aim of this study is to determine the frequency of mismatch repair (MMR) inactivation in ovarian cancer and its association with resistance to platinum-based chemotherapy.

METHODS

We determined, microsatellite instability (MSI) as a marker for MMR inactivation (analysis of BAT25 and BAT26), MLH1 promoter methylation status (methylation specific PCR on bisulfite treated DNA) and mRNA expression of MLH1, MSH2, MSH3, MSH6 and PMS2 (quantitative RT-PCR) in 75 ovarian carcinomas and eight ovarian cancer cell lines

RESULTS

MSI was detected in three of the eight cell lines i.e. A2780 (no MLH1 mRNA expression due to promoter methylation), SKOV3 (no MLH1 mRNA expression) and 2774 (no altered expression of MMR genes). Overall, there was no association between cisplatin response and MMR status in these eight cell lines. Seven of the 75 ovarian carcinomas showed MLH1 promoter methylation, however, none of these showed MSI. Forty-six of these patients received platinum-based chemotherapy (11 non-responders, 34 responders, one unknown response). The resistance seen in the eleven non-responders was not related to MSI and therefore also not to MMR inactivation.

CONCLUSION

No MMR inactivation was detected in 75 ovarian carcinoma specimens and no association was seen between MMR inactivation and resistance in the ovarian cancer cell lines as well as the ovarian carcinomas. In the discussion, the results were compared to that of twenty similar studies in the literature including in total 1315 ovarian cancer patients. Although no association between response and MMR status was seen in the primary tumor the possible role of MMR inactivation in acquired resistance deserves further investigation.

Molecular profiling of platinum resistant ovarian cancer

The aim of this study is to discover a gene set that can predict resistance to platinum-based chemotherapy in ovarian cancer. The study was performed on 96 primary ovarian adenocarcinoma specimens from 2 hospitals all treated with platinum-based chemotherapy. In our search for genes, 24 specimens of the discovery set (5 nonresponders and 19 responders) were profiled in duplicate with 18K cDNA microarrays. Confirmation was done using quantitative RT-PCR on 72 independent specimens (9 nonresponders and 63 responders). Sixty-nine genes were differentially expressed between the nonresponders (n=5) and the responders (n=19) in the discovery phase. An algorithm was constructed to identify predictive genes in this discovery set. This resulted in 9 genes (FN1, TOP2A, LBR, ASS, COL3A1, STK6, SGPP1, ITGAE, PCNA), which were confirmed with qRT-PCR. This gene set predicted platinum resistance in an independent validation set of 72 tumours with a sensitivity of 89% (95% CI: 0.68-1.09) and a specificity of 59% (95% CI: 0.47-0.71)(OR=0.09, p=0.026). Multivariable analysis including patient and tumour characteristics demonstrated that this set of 9 genes is independent for the prediction of resistance (p<0.01). The findings of this study are the discovery of a gene signature that classifies the tumours, according to their response, and a 9-gene set that determines resistance in an independent validation set that outperforms patient and tumour characteristics. A larger independent multicentre study should further confirm whether this 9-gene set can identify the patients who will not respond to platinum-based chemotherapy and could benefit from other therapies.

Cyclopentenyl cytosine primes SK-N-BE(2)c neuroblastoma cells for cytarabine toxicity

CPEC is a potent inhibitor of CTP synthetase and causes depletion of CTP and dCTP pools. AraC is an analog of dCyd and a chemotherapeutic agent. Here, we demonstrate that, upon incubation with CPEC, both the anabolism and cytostatic effect of AraC in SK-N-BE(2)c neuroblastoma cells were increased. Cotreatment of CPEC (50-250 nM) and AraC (37.5-500 nM) decreased the 4-day ED(50) value for AraC 2- to 8-fold in the SK-N-BE(2)c cell line, while pretreatment with CPEC followed by incubation with AraC alone decreased the 4-day ED(50) value for AraC 1- to 19-fold. Preincubation of SK-N-BE(2)c cells with 100 nM CPEC followed by incubation with 500 nM [(3)H]AraC increased the total amount of AraC nucleotides and incorporation of [(3)H]AraC into DNA by 392% and 337%, respectively, compared to non-CPEC-treated cells. When 20 nM [(3)H]AraC was used, the maximum incorporation of [(3)H]AraC into DNA was 1,378% compared to non-CPEC-treated cells. Incorporation of AraC into DNA correlated well with the accumulation of cells in S phase of the cell cycle caused by CPEC. DNA synthesis was almost completely inhibited (>91%) when 100 nM CPEC and 500 nM AraC were combined. CPEC alone and the combination of CPEC and AraC increased caspase-3 activity 3-fold, indicating induction of apoptosis in SK-N-BE(2)c cells. In contrast, AraC alone did not induce caspase-3 activity. Our results demonstrate that low concentrations of CPEC profoundly increase the cytostatic properties of AraC toward SK-N-BE(2)c human neuroblastoma cells.

The cytostatic- and differentiation-inducing effects of cyclopentenyl cytosine on neuroblastoma cell lines

This paper describes the effects of cyclopentenyl cytosine (CPEC) on the proliferation and cell-cycle distribution of the SK-N-BE(2)c and SK-N-SH neuroblastoma cell lines, as well as their ability to recover from treatment with CPEC. The IC50 value of SK-N-BE(2)c for CPEC, determined after 48 hr was 80 nM. SK-N-BE(2)c cells showed a time- and concentration-dependent accumulation in the S-phase of the cell cycle after 2 and 3 days of incubation with 50-250 nM CPEC, followed by a G0/G1-phase arrest after 4 days. After incubation with 50 nM CPEC for 2 days, SK-N-BE(2)c cells fully recovered and resumed logarithmic proliferation. In contrast, a complete and persistent growth arrest occurred when SK-N-BE(2)c cells were incubated for 2 days with 100 or 250 nM CPEC. The IC50 value of SK-N-SH, determined after 48 hr, for CPEC was > or =1 microM. SK-N-SH cells incubated with 250 nM or 1 microM CPEC showed a time-dependent accumulation in the S-phase of the cell cycle, followed by an accumulation in the G0/G1-phase, which reached a maximum of 84.1% after 7 days of incubation with 1 microM CPEC. SK-N-SH cells did not resume proliferation after removal of the drug. In addition, CPEC strongly induced differentiation in SK-N-SH cells. After 48 hr incubation with 250 nM CPEC, 90% of the cell population was differentiated. Both neuronal type and Schwannian type cells were observed. We conclude that at very low concentrations, CPEC has profound cytostatic- and differentiation-inducing effects on the neuroblastoma cells studied.