Prostate Cancer UK: the Blue Skies Forum
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Kirby Blue Skies_Layout 1 19/11/2013 10:42 Page 1 REPORTS 39 Prostate Cancer UK: the Blue Skies Forum ROGER KIRBY, ROS EELES, DAVID NEAL, HASHIM U. AHMED AND DAVID DEARNALEY The second meeting of the Blue Skies Forum took place in Downing College, Cambridge, in April 2013, with the objective of focusing attention on new initiatives in the diagnosis and treatment of prostate cancer, in particular on areas of research that aim to identify aggressive disease. The meeting was hosted by Prostate Cancer UK and supported by The Howard Foundation. GENETIC PREDISPOSITION TO the top 1 per cent of the risk distribution PROSTATE CANCER AND had a 4.7-fold risk relative to the CLINICAL APPLICATION population average and the top 10 per Professor Ros Eeles cent of men had a 2.7-fold relative risk. Interestingly, one of the variants on Prostate-specific antigen has been used as chromosome 17, while increasing the risk a biomarker in prostate cancer since its of prostate cancer, decreases the risk of identification in 1974, but is not sensitive diabetes. The increase in risk with each enough to identify those patients at risk variant is small but the overall effect is of developing high-risk disease. Genetic multiplicative. The detection of these variants have now been identified that variants has the potential for identification can recognise men with nearly a five-fold of targeted drug therapy by discovering relative risk of developing prostate cancer the pathways within which the genes act. compared with the risk to the average man Certain pathways are over-represented in the population. within the genetic variants, such as the Prostate Cancer UK is a registered charity in England pathway for cell adhesion, extracellular and Wales (1005541) and in Scotland (SC039332). Registered company 2653887 A case-control study has been set up matrix modelling and, unsurprisingly, involving 61 research groups worldwide, transcriptional regulation by the androgen Roger Kirby, The Prostate Centre, London; called the PRACTICAL consortium, and receptor (AR). Ros Eeles, Professor of Oncogenetics, the genotyping of 25074 prostate cancer Institute of Cancer Research and cases and 24272 controls from 39 of these Previously, BRCA2 germline mutations have Royal Marsden NHS Foundation Trust; 1 groups has been published. A total of 23 been shown to confer the highest risk of David Neal, Professor of Surgical new prostate cancer loci were identified, prostate cancer (8.6-fold in men aged Oncology/Honorary Consultant Urological 2 16 of which are associated with aggressive ≤65 years), while mutations in BRCA1 Surgeon, Addenbrooke’s Hospital, 3 disease (Figure 1). These and other confer a 3.7-fold risk. Additionally, BRCA2 Cambridge; Hashim U. Ahmed, Clinician discovered loci now explain 30 per cent mutations have been associated with Scientist, University College London; of the familial risk for the disease. aggressive tumour phenotype and poor David Dearnaley, Professor of Uro-oncology, 4 prostate cancer outcome. Further research Institute of Cancer Research and Royal On the basis of combined risks conferred on the involvement of these mutations Marsden NHS Foundation Trust, London by the new and previously known risk loci, has been published recently.5 Germline TRENDS IN UROLOGY & MEN’S HEALTH NOVEMBER/DECEMBER 2013 www.trendsinurology.com Kirby Blue Skies_Layout 1 19/11/2013 10:42 Page 2 REPORTS 40 castrate-resistant prostate cancer (CRPC): 53 cancer cells may act as their synthesisers of androgens; there may be cross-talk 48 signalling via several receptors; the AR may be amplified; and there may be altered 43 expression of transcription factors and 38 co-regulators, which could affect AR binding and signalling. These changes 33 may be present in the early stages of the disease. 28 value) Studies have been conducted to examine p ( 23 10 to which genes the AR binds in the nucleus –log 18 and the functional effects. The method used involves binding of the AR to the 13 genome and then disruption of the DNA and sequencing of specific binding sites. 9 In cell lines, AR binding was shown 6 to co-ordinate a metabolic response promoting aerobic glycolysis.9 A number of 3 novel genes being regulated by AR were identified, including calcium/calmodulin 0 kinase kinase 2 (CAMKK20), which is implicated in the regulation of energy 1 2 3 4 5 6 8 1012141720 XY balance and overexpressed in hormone- Chromosome naïve prostate cancer, but is absent following hormone treatment, reappearing Figure 1. Manhattan plot showing 23 genetic loci associated with increased risk of 9 prostate cancer1 when CRPC develops. CAMKK20 is a potential drug target and inhibition by BRCA1/2 mutations were shown to be Future research includes the recently STO-609 results in inhibition of prostate more frequently associated with Gleason initiated PROFILE study, which will examine cancer growth.9 ≥8 (p=0.00003), T3/T4 stage (p=0.003), the feasibility of targeted prostate cancer nodal involvement (p=0.00005) and screening of men with familial history of Sequencing studies have been conducted metastases at diagnosis (p=0.005) than prostate cancer through prostate biopsy in benign prostate tissue samples and prostate cancer in non-carriers. Cancer- and association of the outcome with prostate cancer tissues from patients who specific survival (CSS) was significantly genetic risk profiling. were untreated, were responders to longer in non-carriers than in carriers androgen deprivation therapy (ADT) or had (15.7 versus 8.6 years). In localised prostate ANDROGEN RECEPTOR CRPC, in order to identify AR binding cancer, five-year CSS and metastasis-free BINDING SITES IN PROSTATE sites.10 The PSA gene was identified as a survival were significantly higher in CANCER binding site, as well as FKBP5, CAMKK2, non-carriers (96 versus 82 per cent Professor David Neal TMPRSS2 and PGC. The AR appears to [p=9 x 10-8] and 93 versus 77 per cent be reprogrammed in CRPC. Unique AR [p=0.0001], respectively). The AR plays a key role in prostate binding sites at E2F, STAT and MYC/MAX growth; subsequent to binding to were identified that were not observed Another genetic association is mutation dihydrotestosterone, it moves into the in cell lines, resulting in the switching in the HOXB13 gene, which is associated nucleus of the prostate cell to initiate a on of the JAK/STAT pathway. A series of with limb structure and androgen biological response through DNA binding. 16 genes have been identified that are signalling, and has been shown to The AR is an important oncogenic driver in upregulated in CRPC and are actually increase the risk of prostate cancer prostate cancer and is reprogrammed in present at diagnosis prior to ADT.10 These 3.63- to 8.66-fold. It is more common high-risk disease. A number of mechanisms genes will provide potential targets for in the Scandinavian population.6–8 may be involved in the development of future therapy. www.trendsinurology.com TRENDS IN UROLOGY & MEN’S HEALTH NOVEMBER/DECEMBER 2013 Kirby Blue Skies_Layout 1 19/11/2013 10:42 Page 3 REPORTS 41 INNOVATION IN SURGICAL THERAPY FOR PROSTATE 35 80 Resonant frequency CANCER 30 Temperature from fluoroptic probe Mr Hashim U. Ahmed 60 25 (°C) Temperature It has been established that not all prostate cancer has the potential to progress to 20 40 invasive and metastatic cancer, and novel 15 imaging and precision biopsy might allow 10 identification of those lesions that are 20 likely to progress and require treatment. 5 To this aim, focal therapy of prostate Resonant frequency change (Hz) cancer has been proposed as an alternative 0 0 that will tailor treatment with consequent -5 minimisation of treatment morbidity. -20 0 20 40 60 80 100 120 A total of 24 focal therapy studies have Time (s) been conducted involving cryosurgery (n=6), high-intensity focused ultrasound Figure 2. Graph illustrating how quickly the heating of tissue can occur for thermoablation when a magnetic field is applied to iron oxide nanoparticles (n=12), photodynamic therapy (n=3), radiofrequency interstitial tumour ablation achieved in the prostates; median urethral TOWARDS PRECISION AND (n=1), brachytherapy (n=1) and mixed and rectal temperatures were 40.5°C PERSONALISED ablation (n=1). Most studies were poorly (range: 38.4–43.6°C) and 39.8°C (range: RADIOTHERAPY reported, retrospective in design and at 38.2–43.4°C), respectively. Computed Professor David Dearnaley an early phase. Overall, complications tomography scans revealed that the and side-effects were low but studies particles stayed within the prostate. A Radical changes in radiotherapy have been struggled to define disease control phase 0 study on magnetic nanoparticle made over the past 10 years through outcomes, although biopsy outcomes thermoablation is to be conducted at improvements in imaging, precision appeared variable. An increasing number University College London involving engineering and increased computational of prospective studies on focal therapy 18 men prior to radical prostatectomy. speeds. This has allowed the development of are now underway, with the UK leading Nanoparticles will be injected into the two different concepts of radiotherapy, many of these. prostates and placement evaluated to namely intensity-modulated radiotherapy determine whether the necessary particle (IMRT) and image-guided radiotherapy Current ablative technologies are not density needed to reach a therapeutic (IGRT), which provide very accurate perfect, and ongoing research to improve temperature can be achieved. The target treatment. Still lacking in our current the care of men with localised prostate temperature is 70°C with the application of knowledge is individual tumour sensitivities cancer is needed. Magnetic nanoparticle 100s of current. A phase 1 study will also to radiotherapy, primarily due to lack of thermoablation has been researched as a be conducted to examine the ablative access to tissue samples.