Intratumoural evolutionary landscape of high-risk prostate cancer: the PROGENY study of genomic and immune parameters

BACKGROUND

Intratumoural heterogeneity (ITH) is well recognised in prostate cancer (PC), but its role in high-risk disease is uncertain. A prospective, single-arm, translational study using targeted multiregion prostate biopsies was carried out to study genomic and T-cell ITH in clinically high-risk PC aiming to identify drivers and potential therapeutic strategies.

PATIENTS AND METHODS

Forty-nine men with elevated prostate-specific antigen and multiparametric-magnetic resonance imaging detected PC underwent image-guided multiregion transperineal biopsy. Seventy-nine tumour regions from 25 patients with PC underwent sequencing, analysis of mutations, copy number and neoepitopes combined with tumour infiltrating T-cell subset quantification.

RESULTS

We demonstrated extensive somatic nucleotide variation and somatic copy number alteration heterogeneity in high-risk PC. Overall, the mutational burden was low (0.93/Megabase), but two patients had hypermutation, with loss of mismatch repair (MMR) proteins, MSH2 and MSH6. Somatic copy number alteration burden was higher in patients with metastatic hormone-naive PC (mHNPC) than in those with high-risk localised PC (hrlPC), independent of Gleason grade. Mutations were rarely ubiquitous and mutational frequencies were similar for mHNPC and hrlPC patients. Enrichment of focal 3q26.2 and 3q21.3, regions containing putative metastasis drivers, was seen in mHNPC patients. We found evidence of parallel evolution with three separate clones containing activating mutations of β-catenin in a single patient. We demonstrated extensive intratumoural and intertumoural T-cell heterogeneity and high inflammatory infiltrate in the MMR-deficient (MMRD) patients and the patient with parallel evolution of β-catenin. Analysis of all patients with activating Wnt/β-catenin mutations demonstrated a low CD8+/FOXP3+ ratio, a potential surrogate marker of immune evasion.

CONCLUSIONS

The PROGENY (PROstate cancer GENomic heterogeneitY) study provides a diagnostic platform suitable for studying tumour ITH. Genetic aberrations in clinically high-risk PC are associated with altered patterns of immune infiltrate in tumours. Activating mutations of Wnt/β-catenin signalling pathway or MMRD could be considered as potential biomarkers for immunomodulation therapies.

CLINICAL TRIALS.GOV IDENTIFIER

NCT02022371.

The use of mass depletion-mass flux reduction relationships during pumping to determine source zone mass of a reactive brominated-solvent DNAPL

Mass depletion-mass flux relationships usually applied to a groundwater plume were established at field scale for groundwater pumped from within the source zone of a dense non-aqueous phase liquid (DNAPL). These were used as part of multiple lines of evidence in establishing the DNAPL source mass and architecture. Simplified source mass-dissolved concentration models including those described by exponential, power, and error functions as well as a rational mass equation based on the equilibrium stream tube approach were fitted to data from 285 days of source zone pumping (SZP) from a single well which removed 152 kg of dissolved organics from a multi-component, reactive brominated solvent DNAPL. The total molar concentration of the source compound, tetrabromoethane and its daughter products was used as a single measure of contaminant concentration to relate to source mass. A partitioning inter-well tracer test (PITT) conducted prior to the SZP provided estimates of groundwater travel times, enabling parameterisation of the models. After accounting for capture of the down-gradient dissolved plume, all models provided a good fit to the observed data. It was shown that differentiation between models would only emerge after appreciably more pumping from the source zone. The model fits were not particularly sensitive to the exponent parameters and variance of groundwater travel time. In addition, the multi-component nature of the DNAPL did not seem to affect the utility of the models for the period examined. Estimates of the DNAPL mass prior to the start of SZP from the models were greatest where the log of the variance of travel time was used explicitly in the source depletion models (mean 295kg) compared to where the associated power exponent and variance was fitted freely (mean 258 kg). The estimates of source mass were close to that of 220kg determined from the PITT. In addition to the PITT, multi-level groundwater sampling from within the source zone provided important supporting information for developing the conceptual model of the source zone. It is concluded that SZP may be an effective and relatively simple means for characterising DNAPL source zones.

Measurement of shoulder joint kinaesthesia

SUMMARY. Loss of kinaesthesia has been identified as a factor in recurrent or persistent problems following glenohumeral dislocation. However, accurate measurement of shoulder kinaesthesia remains a difficult task in the clinical setting. This study investigated the use of the Kincom dynamometer for measuring the ability of a subject to reproduce a shoulder joint angle with a passive and active test. The tests were applied to two subject groups, (normal and patient) and the results were compared with those of a standard clinical test. The results of the Kincom tests demonstrate a statistically significant difference between the normal and patient groups (F((1,140)) = 53.0; P < 0.001). The difference between the means for the two groups was 1.2 degrees which indicates the precision of shoulder kinaesthetic sense. All subjects were more accurate with the active test compared to the passive test (F((1,140)) = 36.5; P < 0.001). Reliability of the Kincom tests was evaluated over 3 days and a significant difference was found between day one and day three for both groups (F((2,140)) = 3.5; P < 0.05) suggesting a learning effect had occurred. There was no significant difference between the Kincom active test and the clinical test (F((1,28)) = 1.86; P = 0.18); however, the difference between the Kincom passive test and the clinical test was significant (F((1,28)) = 10.74; P < 0.01). The clinical test did not demonstrate a statistically significant difference between the two subject groups (t(28 = 1); P = 0.05). Copyright 1996 Harcourt Publishers Ltd.

Design for a constant peak current defibrillator

A damped sine wave defibrillator that is capable of delivering a constant peak discharge current over a wide range of patient thoracic impedance is shown to be theoretically possible. This is realized in practice by the technique of storing an amount of energy above that required for delivery, and dumping the excess charge when the discharge current has reached a predetermined level, the dumping being triggered by a current sensor. A larger than normal inductance assists in swamping the effect of varying impedance and produces a smooth waveform. The preselected peak current can be delivered with a variation of about +/- 6% to 95% of a normal patient population. The energy expended in a simulated patient circuit is somewhat lower than for conventional defibrillators.

The feasibility of detecting His-bundle activity from the body surface

Electrocardiograms were recorded from human patients using a bipolar chest lead together with simultaneous His-bundle electrograms. These were then subjected to the technique of signal averaging in an attempt to extract His-bundle activity from the surface record. This was successful in three out of 10 cases subjected to the truly non-invasive surface technique. Methods are discussed by which the technique could be improved.