Prognostic Significance of Pretreatment Immune Cell Infiltration in Muscle Invasive Bladder Cancer Treated with Definitive Chemoradiation: Analysis of NRG RTOG 0524 and 0712

PURPOSE/OBJECTIVE(S)

Chemoradiation therapy (CRT) is an organ conserving approach in the treatment of locally advanced bladder cancer. Chemoradiation is thought to potentially result in immunogenic stimulation, and bladder cancer is often a tumor with high immune cell infiltration. Thus, we aimed to profile the tumor immune microenvironment of bladder cancer and identify prognostic immune biomarkers for CRT response by profiling tumor samples from NRG/RTOG 0524 and 0712, two prospective trials of CRT in muscle invasive bladder cancer (MIBC).

MATERIALS/METHODS

Pretreatment tissue samples from both trials were profiled using Cofactor Genomics ImmunoPrism, an RNA sequencing assay that uses gene expression profiles to quantify immune cell populations in the tumor microenvironment (TME). Differential gene expression was estimated for different immune cell type proportions across samples. Kaplan-Meier survival analysis and log rank tests were performed to evaluate differences in overall survival (OS) stratified by genes influenced by immune cell proportions or genes associated with immune response signatures.

RESULTS

A total of 70 samples (43 from RTOG 0524 and 27 from RTOG 0712) underwent analysis using the ImmunoPrism assay. Immune cell proportions were as follows: CD8 T cells: median 1.2%, CD4 T cells: median 0.8%, Treg cells: median 9.2%, CD19 B cells: median 5.1%, M2 macrophages: median 0.8%, M1 macrophages: median 0%. Unbiased clustering based on gene expression profiles driven by immune cell proportions demonstrated two groups: cluster 1 with a low percentage of immune cells and shorter OS (median 31 months) and cluster 2 with a high percentage of immune cells and longer OS (median 101 months, p = 0.036). Higher expression of genes associated with T cell infiltration (CD8A and ICOS) was associated with improved OS (104 vs 35 months, p = 0.028, HR = 0.48 (0.25 - 0.94), p = 0.031) as was higher expression of IDO1, which is associated with the interferon gamma pathway (104 vs 35 months, p = 0.042, HR = 0.49 (0.24 - 0.99), p = 0.046).

CONCLUSION

Bladder tumors have a wide range of immune cell infiltration in the TME. Increased immune cell proportions are prognostic for OS following CRT, as well as a higher expression of genes associated with T cell infiltration interferon gamma signaling. These findings have implications for the integration of immunotherapy in the definitive management of MIBC; and can be explored further in the ongoing NRG/SWOG 1806 trial.

Analyses of circulating tumor cell (CTC) dynamics and treatment response in prostate cancer using the CTC-chip microfluidic device

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Background: The CTC-Chip reliably detects CTCs in patients with localized and metastatic prostate cancer. In localized disease, CTCs may be indicative of tumor invasiveness. In the metastatic setting, CTCs may be useful in monitoring response to therapy. Molecular analyses of CTCs through this minimally invasive technique may provide insights into disease behavior, whereas sampling of metastatic deposits in bone (the predominant site of prostate metastasis) is not feasible. Methods: Peripheral blood was collected from patients undergoing treatment. CTCs were captured on the CTC-Chip. Quantities were determined using cytokeratin- and PSA-based staining and enumeration. In some cases, molecular analyses for the TMPRSS2:ERG chromosomal translocation were performed using FISH in intact cells or nuclei, or RT-PCR in extracted RNA. Subgroups of patients (n) included: localized disease undergoing prostatectomy (25), and metastatic disease undergoing either androgen deprivation therapy (ADT) (12) or docetaxel chemotherapy (5). Results: PSA-stained CTCs were captured in all patients. In localized disease, CTC quantities fell to undetectable levels 7–14 days after surgery; some patients exhibited an immediate decline while others had a delayed decline (>24 hours). In patients with metastatic disease undergoing either ADT or chemotherapy, CTC quantities generally corresponded with changes in serum PSA and radiographic assessments. Approximately 50% of patients exhibited the TMPRSS2:ERG translocation. Conclusions: These studies are the first to use the highly sensitive CTC-Chip technology to assess dynamic changes in CTCs in patients undergoing prostatectomy, ADT, or chemotherapy. Ongoing larger studies will assess whether patterns of CTC changes predict recurrence or treatment response. Molecular characterization of CTCs may provide new insights into prostate cancer biology, clinical behavior, and therapeutic targets.

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The androgen receptor gene GGN microsatellite and prostate cancer risk

The androgen receptor (AR) gene contains a polymorphic GGN microsatellite in exon 1, which encodes polyglycine in the amino terminus of the AR. Previous work has shown that a polymorphic region of CAG repeats also in exon 1 is inversely related to the ability of the AR to transactivate other genes and to prostate cancer risk. We investigated whether AR gene GGN repeat length is related to prostate cancer in a nested study of 582 cases and 794 controls matched on age and smoking status in the Physicians' Health Study. DNA was prepared from archived blood. Using PCR, the region surrounding the GGN repeat was amplified. Fluorescence-labeled primers were used such that the fragment produced could be sized using polyacrylamide gels and Genescan software. We estimated odds ratios and 95% confidence intervals from logistic models controlling for the matching variables for the relation between GGN repeat length and total prostate cancer and by stage/grade and by age at diagnosis. Among controls, the most frequent GGN repeat lengths were 23 (53.5%) and 24 (34.0%), with a range of 10-29. There was no statistically significant difference in the mean GGN repeat length between cases (23.13) and controls (23.05). However, cases had a narrower spread of repeats lengths (parametric test, P = 0.03; nonparametric test, P = 0.07) than controls, with fewer extreme lengths in either direction. The risk of total prostate cancer was slightly increased for a GGN repeat length of 23 compared to all others (odds ratio, 1.20; 95% confidence interval 0.97-1.49); risk did not vary by tumor stage/grade. For every one repeat deviation in either direction from 23, the risk of prostate cancer decreased by 8% (P = 0.04). Although the AR gene GGN repeat probably plays only a modest role in prostate cancer, the observed relation of this repeat with prostate cancer risk supports the evaluation of the effect of GGN repeat length on AR transactivation.

A polymorphism of the 5 alpha-reductase gene and its association with prostate cancer: a case-control analysis

Prostate cancer (CaP) is the most commonly diagnosed, nondermatological cancer in the United States. The development and progression of CaP is influenced by androgens. 5 alpha-Reductase, type II, converts testosterone to dihydrotestosterone and is critical to the development of the prostate. A TA dinucleotide repeat polymorphism exists in the 3' untranslated region of the 5 alpha-reductase type II gene. 5 alpha-Reductase alleles with longer TA repeats are more common in African-Americans, the group with the highest incidence of CaP. It has been hypothesized that the longer TA repeat alleles might be associated with increased risk of CaP. We studied this potential association within the Physician's Health Study, a predominantly Caucasian cohort study. Using PCR we identified the TA genotype in 590 men with CaP and 802 age-matched controls. The frequency of each allele in the controls was TA(0), 0.87, TA(9), 0.13, and TA(18), 0.01. Homozygotes for the longer TA alleles, TA(9) and TA(18), were underrepresented among cases with an odds ratio of 0.47 (confidence interval, 0.20-1.12), but this was not statistically significant (P = 0.08, two tailed). Our analysis does not support the prior hypothesis that longer TA alleles confer an increased risk of CaP in a predominantly Caucasian population; in fact, longer TA alleles are more prevalent in men without CaP.

Penile mass caused by the newly described organism Mycobacterium celatum

We report a penile infection in a man with the acquired immunodeficiency syndrome caused by a newly described infectious organism, Mycobacterium celatum. Mycobacterium tuberculosis is the only mycobacterial species previously reported to cause infection in the penis. This is only the third documented human infection with M celatum, and the first to involve the genitourinary system.

Physiological hyperinsulinemia inhibits myocardial protein degradation in vivo in the canine heart

Myocardial protein turnover in vivo was examined in anesthetized dogs following a 16- or 36-hour fast and again during a hyperinsulinemic (2 mU/kg per minute) euglycemic clamp with or without amino acid replacement or during saline infusion. We measured myocardial phenylalanine balance and rates of protein synthesis and degradation, using the extraction of intravenously infused L-[ring-2,6-3H]phenylalanine and the dilution of its specific activity across the heart at isotopic steady state. After both a 16-hour (n = 19) and 36-hour fast (n = 10), there was net myocardial release of phenylalanine indicated by the negative balances for phenylalanine of -52 +/- 9 (p less than 0.001) and -38 +/- 9 (p less than 0.005) nmol/min, respectively. Overall, the basal rate of myocardial protein degradation was lower in the 36-hour-fasted animals (81 +/- 13 versus 121 +/- 12 nmol/min, p less than 0.05). Myocardial phenylalanine balance and rates of protein synthesis and degradation did not change during insulin and glucose infusion in the 36-hour-fasted animals (n = 10). In these animals, there was a 30-40% decline in plasma amino acid concentrations, including branched chain (p less than 0.001) and essential amino acids (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo measurement of myocardial protein turnover using an indicator dilution technique

We applied a nondestructive tracer technique, previously developed for measuring skeletal muscle protein turnover, to the measurement of myocardial protein turnover in vivo. During a continuous infusion of L-[ring-2,6-3H]phenylalanine to anesthetized, overnight-fasted dogs, we measured the uptake of radiolabeled phenylalanine from plasma and the release of unlabeled phenylalanine from myocardial proteolysis using arterial and coronary sinus catheterization and analytic methods previously applied to skeletal muscle. Using these measurements, together with a model of myocardial protein synthesis that assumes rapid equilibration of tracer specific activity between myocardial phenylalanyl-tRNA and circulating phenylalanine, we estimated the rates of heart protein synthesis and degradation. The rate of heart protein synthesis was also estimated directly from the incorporation of labeled phenylalanine into tissue protein. The use of [3H]phenylalanine was compared with L-[1-14C]leucine in the measurement of heart protein turnover in dogs given simultaneous infusion of both tracers. Leucine uptake and release by the myocardium exceeded that of phenylalanine by 3.1 +/- 0.4- and 1.7 +/- 0.3-fold, respectively, consistent with leucine's 2.4-fold greater abundance in heart protein and its metabolism via other pathways. Phenylalanine is the preferred tracer for use with this method because of its limited metabolic fate in muscle. One theoretical limitation to the method, slow equilibration of circulating labeled phenylalanine with myocardial phenylalanyl-tRNA, was resolved by comparison of these specific activities after a 30-minute infusion of labeled phenylalanine in the rat. A second, empirical limitation involves precision in the measurement of the small decrements in phenylalanine specific activity that occur with each pass of blood through the coronary circulation. This was addressed by improving the precision of both the measurements of phenylalanine concentration and phenylalanine specific activity using high-performance liquid chromatography. We conclude that the in vivo measurement of phenylalanine tracer exchange across the myocardium permits the nondestructive estimation of heart protein turnover in the intact animal.