The interplay of growth differentiation factor 15 (GDF15) expression and M2 macrophages during prostate carcinogenesis

Combining tissue biomarkers with mpMRI to diagnose clinically significant prostate cancer. Analysis of 21 biomarkers in the PICTURE study

BACKGROUND

Serum PSA and digital rectal examination remain the key diagnostic tools for detecting prostate cancer. However, due to the limited specificity of serum PSA, the applicability of this marker continues to be controversial. Recent use of image-guided biopsy along with pathological assessment and the use of biomarkers has dramatically improved the diagnosis of clinically significant cancer. Despite the two modalities working together for diagnosis biomarker research often fails to correlate findings with imaging.

METHODS AND RESULTS

We looked at 21 prostate cancer biomarkers correlating our results with mpMRI data to investigate the hypothesis that biomarkers along with mpMRI data make a powerful tool to detect clinically significant prostate cancer. Biomarkers were selected based on the existing literature. Using a tissue microarray comprised of samples from the PICTURE study, with biopsies at 5 mm intervals and mpMRI data we analysed which biomarkers could differentiate benign and malignant tissue. Biomarker data were also correlated with pathological grading, mpMRI, serum PSA, age and family history. AGR2, CD10 and EGR protein expression was significantly different in both matched malignant and benign tissues. AMACR, ANPEP, GDF15, MSMB, PSMA, PTEN, TBL1XR1, TP63, VPS13A and VPS28 showed significantly different expression between Gleason grades in malignant tissue. The majority of the biomarkers tested did not correlate with mpMRI data. However, CD10, KHDRBS3, PCLAF, PSMA, SIK2 and GDF15 were differentially expressed with prostate cancer progression. AMACR and PTEN were identified in both pathological and image data evaluation.

CONCLUSIONS

There is a high demand to develop biomarkers that would help the diagnosis and prognosis of prostate cancer. Tissue biomarkers are of particular interest since immunohistochemistry remains a cheap, reliable method that is widely available in pathology departments. These results demonstrate that testing biomarkers in a cohort consistent with the current diagnostic pathway is crucial to identifying biomarker with potential clinical utility.

Hallmarks of Cancer Cachexia: Sexual Dimorphism in Related Pathways

Cancer-associated cachexia (CAC), also known as wasting syndrome, is a systemic condition that affects multiple tissues and organs via a variety of metabolic pathways. Systemic inflammation, progressive weight loss, depletion of adipose tissue, and skeletal muscle impairment are some of the hallmark features of cachexia. Despite various studies on the clinical features of CAC, the complexity of the syndrome continues to pose significant challenges in clinical practice, leading to late diagnoses and the absence of a standardised treatment. Men and women respond differently to CAC, which may be prompted by the pre-existing physiologic sex differences. This review presents the sexual dimorphism associated with the hallmark pathways involved in CAC. A comprehensive understanding of sexual dimorphism in these pathways could drive research on cachexia to prioritise the inclusion of more females in related studies in order to achieve personalised sex-based therapeutic approaches and, consequently, enhance treatment efficacy and better patient outcomes.

GDF15-mediated enhancement of the Warburg effect sustains multiple myeloma growth via TGFβ signaling pathway

The Warburg effect, characterized by the shift toward aerobic glycolysis, is closely associated with the onset and advancement of tumors, including multiple myeloma (MM). Nevertheless, the specific regulatory mechanisms of glycolysis in MM and its functional role remain unclear. In this study, we identified that growth differentiation factor 15 (GDF15) is a glycolytic regulator, and GDF15 is highly expressed in MM cells and patient samples. Through gain-of-function and loss-of-function experiments, we demonstrated that GDF15 promotes MM cell proliferation and inhibits apoptosis. Moreover, GDF15 enhances Warburg-like metabolism in MM cells, as evidenced by increased glucose uptake, lactate production, and extracellular acidification rate, while reducing oxidative phosphorylation. Importantly, the tumor-promoting effects of GDF15 in MM cells are fermentation-dependent. Mechanistically, GDF15 was found to promote the expression of key glycolytic genes, particularly the glucose transporter GLUT1, through the activation of the TGFβ signaling pathway. Pharmacological inhibition of the TGFβ signaling pathway effectively abrogated the oncogenic activities of GDF15 in MM cells, including cell proliferation, apoptosis, and fermentation. In vivo experiments using a subcutaneous xenotransplanted tumor model confirmed that GDF15 knockdown led to a significant reduction in tumor growth, while GDF15 overexpression promoted tumor growth. Overall, our study provides insights into the molecular mechanisms underlying MM pathogenesis and highlights the potential of targeting GDF15-TGFβ signaling -glycolysis axis as a therapeutic approach for future therapeutic interventions in MM.

Phthalate exposure induces microRNA-5010/Nrf2-EGR1/GDF15 signaling expression in prostate cancer

Phthalate exposure is linked to prostate enlargement through sex hormonal changes and oxidative stress. However, its role and action mechanism in prostate cancer remain unclear. This study examined two patient cohorts: 204 patients undergoing prostate biopsy (24 benign and 180 malignancies) and 85 with confirmed prostate cancer receiving robotic-assisted radical prostatectomy. Urine samples, collected with informed consent, were analyzed for urinary DEHP metabolites using HPLC-MS and ELISA. Patients with prostate cancer exhibited significantly higher urinary MEOHP and ΣDEHP metabolite levels than those who underwent benign biopsy (unpaired t-test, p = 0.027 and 0.039, respectively). MIR-5010 upregulation and MIR-205 downregulation were observed in two paired small RNA sequencing analyses (urine pellets of benign vs. malignant patients and PC3 cells without or with DEHP treatment), correlating with tumor staging in the TCGA prostate cancer cohort. Unlike MIR-205, a known tumor suppressor gene in prostate cancer, gene set enrichment analysis revealed that higher MIR-5010 expression was linked to increased Nrf-2 downstream signaling (enriched score: 0.35; p = 0.17). In vitro assays in prostate cancer cells showed that DEHP enhanced Nrf-2 protein expression and its downstream signaling molecules (i.e., SOD2, Heme oxygenase-1, and EGR-1) while increasing GDF15 mRNA expression via EGR-1 regulation in a dose- and time-dependent manner. Furthermore, urinary GDF15 levels were positively associated with urinary MEOHP and MEHP metabolites in the biopsy cohort (p = 0.0007 and 0.011, respectively) and with urinary oxidative stress marker 8-OHdG, aggressive marker VEGF, and CCL2/MCP-1 levels in the prostatectomy cohort (p = 0.0004, 0.006, and 0.0034, respectively). These findings suggest that phthalate exposure induces Nrf-2 and its downstream signaling (i.e., EGR-1/GDF-15) through microRNA regulation, contributing to prostate cancer aggressiveness.

Multiplex imaging of localized prostate tumors reveals altered spatial organization of AR-positive cells in the microenvironment

Mapping the spatial interactions of cancer, immune, and stromal cell states presents novel opportunities for patient stratification and for advancing immunotherapy. While single-cell studies revealed significant molecular heterogeneity in prostate cancer cells, the impact of spatial stromal cell heterogeneity remains poorly understood. Here, we used cyclic immunofluorescent imaging on whole-tissue sections to uncover novel spatial associations between cancer and stromal cells in low- and high-grade prostate tumors and tumor-adjacent normal tissues. Our results provide a spatial map of single cells and recurrent cellular neighborhoods in the prostate tumor microenvironment of treatment-naive patients. We report unique populations of mast cells that show distinct spatial associations with M2 macrophages and regulatory T cells. Our results show disease-specific neighborhoods that are primarily driven by androgen receptor-positive (AR+) stromal cells and identify inflammatory gene networks active in AR+ prostate stroma.

Detailed role of SR-A1 and SR-E3 in tumor biology, progression, and therapy

The first host defense systems are the innate immune response and the inflammatory response. Among innate immune cells, macrophages, are crucial because they preserve tissue homeostasis and eradicate infections by phagocytosis, or the ingestion of particles. Macrophages exhibit phenotypic variability contingent on their stimulation state and tissue environment and may be detected in several tissues. Meanwhile, critical inflammatory functions are played by macrophage scavenger receptors, in particular, SR-A1 (CD204) and SR-E3 (CD206), in a variety of pathophysiologic events. Such receptors, which are mainly found on the surface of multiple types of macrophages, have different effects on processes, including atherosclerosis, innate and adaptive immunity, liver and lung diseases, and, more recently, cancer. Although macrophage scavenger receptors have been demonstrated to be active across the disease spectrum, conflicting experimental findings and insufficient signaling pathways have hindered our comprehension of the molecular processes underlying its array of roles. Herein, as SR-A1 and SR-E3 functions are often binary, either protecting the host or impairing the pathophysiology of cancers has been reviewed. We will look into their function in malignancies, with an emphasis on their recently discovered function in macrophages and the possible therapeutic benefits of SR-A1 and SR-E3 targeting.

Macrophages as a Source and Target of GDF-15

Growth differentiation factor 15 (GDF-15) is a multifunctional cytokine that belongs to the transforming growth factor-beta (TGF-β) superfamily. GDF-15 is involved in immune tolerance and is elevated in several acute and chronic stress conditions, often correlating with disease severity and patient prognosis in cancer172 and metabolic and cardiovascular disorders. Despite these clinical associations, the molecular mechanisms orchestrating its effects remain to be elucidated. The effects of GDF-15 are pleiotropic but cell-specific and dependent on the microenvironment. While GDF-15 expression can be stimulated by inflammatory mediators, its predominant effects were reported as anti-inflammatory and pro-fibrotic. The role of GDF-15 in the macrophage system has been increasingly investigated in recent years. Macrophages produce high levels of GDF-15 during oxidative and lysosomal stress, which can lead to fibrogenesis and angiogenesis at the tissue level. At the same time, macrophages can respond to GDF-15 by switching their phenotype to a tolerogenic one. Several GDF-15-based therapies are under development, including GDF-15 analogs/mimetics and GDF-15-targeting monoclonal antibodies. In this review, we summarize the major physiological and pathological contexts in which GDF-15 interacts with macrophages. We also discuss the major challenges and future perspectives in the therapeutic translation of GDF-15.

Constructing lactylation-related genes prognostic model to effectively predict the disease-free survival and treatment responsiveness in prostate cancer based on machine learning

Background: Prostate cancer (PCa) is one of the most common malignancies in men with a poor prognosis. It is therefore of great clinical importance to find reliable prognostic indicators for PCa. Many studies have revealed the pivotal role of protein lactylation in tumor development and progression. This research aims to analyze the effect of lactylation-related genes on PCa prognosis. Methods: By downloading mRNA-Seq data of TCGA PCa, we obtained the differential genes related to lactylation in PCa. Five machine learning algorithms were used to screen for lactylation-related key genes for PCa, then the five overlapping key genes were used to construct a survival prognostic model by lasso cox regression analysis. Furthermore, the relationships between the model and related pathways, tumor mutation and immune cell subpopulations, and drug sensitivity were explored. Moreover, two risk groups were established according to the risk score calculated by the five lactylation-related genes (LRGs). Subsequently, a nomogram scoring system was established to predict disease-free survival (DFS) of patients by combining clinicopathological features and lactylation-related risk scores. In addition, the mRNA expression levels of five genes were verified in PCa cell lines by qPCR. Results: We identified 5 key LRGs (ALDOA, DDX39A, H2AX, KIF2C, RACGAP1) and constructed the LRGs prognostic model. The AUC values for 1 -, 3 -, and 5-year DFS in the TCGA dataset were 0.762, 0.745, and 0.709, respectively. The risk score was found a better predictor of DFS than traditional clinicopathological features in PCa. A nomogram that combined the risk score with clinical variables accurately predicted the outcome of the patients. The PCa patients in the high-risk group have a higher proportion of regulatory T cells and M2 macrophage, a higher tumor mutation burden, and a worse prognosis than those in the low-risk group. The high-risk group had a lower IC50 for certain chemotherapeutic drugs, such as Docetaxel, and Paclitaxel than the low-risk group. Furthermore, five key LRGs were found to be highly expressed in castration-resistant PCa cells. Conclusion: The lactylation-related genes prognostic model can effectively predict the DFS and therapeutic responses in patients with PCa.

Patterns of B-cell lymphocyte expression changes in pre- and post-malignant prostate tissue are associated with prostate cancer progression

BACKROUND

Inflammation characterized by the presence of T and B cells is often observed in prostate cancer, but it is unclear how T- and B-cell levels change during carcinogenesis and whether such changes influence disease progression.

METHODS

The study used a retrospective sample of 73 prostate cancer cases (45 whites and 28 African Americans) that underwent surgery as their primary treatment and had a benign prostate biopsy at least 1 year before diagnosis. CD3+, CD4+, and CD20+ lymphocytes were quantified by immunohistochemistry in paired pre- and post-diagnostic benign prostate biopsy and tumor surgical specimens, respectively. Clusters of similar trends of expression across two different timepoints and three distinct prostate regions-benign biopsy glands (BBG), tumor-adjacent benign glands (TAG), and malignant tumor glandular (MTG) regions-were identified using Time-series Anytime Density Peaks Clustering (TADPole). A Cox proportional hazards model was used to estimate the hazard ratio (HR) of time to biochemical recurrence associated with region-specific lymphocyte counts and regional trends.

RESULTS

The risk of biochemical recurrence was significantly reduced in men with an elevated CD20+ count in TAG (HR = 0.81, p = 0.01) after adjusting for covariates. Four distinct patterns of expression change across the BBG-TAG-MTG regions were identified for each marker. For CD20+, men with low expression in BBG and higher expression in TAG compared to MTG had an adjusted HR of 3.06 (p = 0.03) compared to the reference group that had nominal differences in CD20+ expression across all three regions. The two CD3+ expression patterns that featured lower CD3+ expression in the BBG compared to the TAG and MTG regions had elevated HRs ranging from 3.03 to 4.82 but did not reach statistical significance.

CONCLUSIONS

Longitudinal and spatial expression patterns of both CD3+ and CD20+ suggest that increased expression in benign glands during prostate carcinogenesis is associated with an aggressive disease course.

Evaluation of CD47 in the Suppressive Tumor Microenvironment and Immunotherapy in Prostate Cancer

Background

CD47 has high levels of expression in malignant cancer cells, which binds to SIRP-α to release the "don't eat me" signal and prevents mononuclear macrophages from phagocytosing the cells. Resistance to drugs and metastases are potential barriers for prostate cancer endocrine therapy. Although immunotherapy for tumors has developed rapidly in the last few decades, its effectiveness in treating prostate cancer is unsatisfactory. Prostate cancer has a high-expression level of CD47. Therefore, a novel approach for potential immunotherapy may be provided by investigating the relationship among CD47 and the infiltration of immune cells in the prostate carcinoma.

Methods

The GEPIA database was utilized to compare the abundance of CD47 in malignant tissues with tissues that were normal. Furthermore, the function of CD47 in prostate carcinoma was assessed by CancerSEA. The association among CD47 and the tumor microenvironment was assessed utilizing the TISCH single cell data database. By using TIMER, the connection among CD47 and immunological invasion of prostate cancer was explored. Moreover, macrophages were cocultured with mouse prostate cancer cell RM-1 blocked by CD47 antibody to observe the changes in phagocytosis efficiency in vitro.

Results

Expression level of CD47 is upregulated in prostate carcinoma, and it is closely connected with prostate cancer's inadequate immune invasion. CD47 antibody blocking promotes macrophage phagocytosis of RM-1.

Conclusion

Our research demonstrates a closely relationship among CD47 and the immunological microenvironment of prostate cancer, and blocking CD47 can promote macrophages to phagocytosis of prostate cancer cells. Therefore, CD47 may provide novel strategies for potential immunotherapy of prostate cancer.

Growth differentiation factor 15 (GDF-15) in endocrinology

Human growth differentiation factor 15 (GDF-15) is a widely distributed protein that has shown to play multiple roles in both physiological and pathological conditions. In healthy individuals, GDF-15 is mainly expressed in the placenta, followed by the prostate, although low levels of expression have also been detected in different organs. GDF-15 acts through a recently identified receptor called glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) which signals through the rearranged during transfection (RET) tyrosine kinase receptor. The effects of GDF-15 are pleiotropic and include appetite regulation, and actions on metabolism, pregnancy, cell survival, immune response, and inflammation. GDF-15 also plays different roles in the pathophysiology of cardiovascular disease, autoimmunity, cancer-associated anorexia/cachexia, and diabetes. In recent years, several studies have reported a link between GDF-15 and the endocrine system. In this review, we up-date and summarize the relevant investigations of the relationships between GDF-15 and different endocrine conditions. We also assess the potential pathogenic role and potential therapeutic applications of GDF-15 in the field of endocrinology.

Raised circulating soluble growth differentiation factor 15 is negatively associated with testosterone level in hypogonadic men with type 2 diabetes

AIMS

Epidemiological studies consistently show that decreases in serum testosterone level are observed more frequently in men with type 2 diabetes mellitus (T2DM), while clinical investigations have demonstrated that an increased level of circulating growth differentiation factor-15 (GDF-15) are also related closely to T2DM. The aim of this study was to examine the potential relationship between serum GDF-15 levels and hypogonadism in Chinese male patients with T2DM.

MATERIALS AND METHODS

A total of 305 T2DM men were recruited between July 2020 and August 2021. GDF-15 and total testosterone concentrations were quantified by an enzyme-linked immunosorbent assay and LC/MS mass spectrometry, respectively. Multiple linear regression analysis, logistic regression, and restricted cubic splined models were used to examine the correlation between GDF-15 levels and hypogonadism in these patients.

RESULTS

When compared with T2DM patients without hypogonadism circulating GDF-15 levels were significantly higher in the hypogonadism group [1081.83 (746.79,1539.94) versus 779.49 (548.46,1001.27), p < 0.001] and were associated positively with hypogonadism in unadjusted and fully adjusted multivariate regression models (p < 0.01). The fully adjusted regression coefficients with 95% confidence intervals for circulating GDF-15 and testosterone deficiency were -1.795 (-2.929, -0.661). Serum GDF-15 levels were also associated positively with testosterone deficiency in each logistic regression model (p < 0.05), while after adjustment for all risk factors, the same findings were obtained in the restricted cubic splined models (p < 0.01).

CONCLUSIONS

In hypogonadal men with T2DM, an elevated serum GDF-15 level is associated negatively with serum testosterone concentration. GDF-15 may be a novel cytokine related to T2DM men with hypogonadism.

Increased Density of Growth Differentiation Factor-15+ Immunoreactive M1/M2 Macrophages in Prostate Cancer of Different Gleason Scores Compared with Benign Prostate Hyperplasia

Simple Summary

Prostate cancer (PCa) is the second most diagnosed cancer and cause of death in men worldwide. The main challenge is to discover biomarkers for malignancy to guide the physician towards optimized diagnosis and therapy. There is recent evidence that growth differentiation factor-15 (GDF-15) is elevated in cancer patients. Therefore, we aimed to decipher GDF-15+ cell types and their density in biopsies of human PCa patients with Gleason score (GS)6–9 and benign prostate hyperplasia (BPH). Here we show that the density of GDF-15+ cells, mainly identified as interstitial macrophages (MΦ), was higher in GS6–9 than in BPH, and, thus, GDF-15 is intended to differentiate patients with high GS vs. BPH, as well as GS6 vs. GS7 (or even with higher malignancy). Some GDF-15+ MΦ showed a transepithelial migration into the glandular lumen and, thus, might be used for measurement in urine/semen. Taken together, GDF-15 is proposed as a novel tool to diagnose PCa vs. BPH or malignancy (GS6 vs. higher GS) and as a potential target for anti-tumor therapy. GDF-15 in seminal plasma and/or urine could be utilized as a non-invasive biomarker of PCa as compared to BPH.

Abstract

Although growth differentiation factor-15 (GDF-15) is highly expressed in PCa, its role in the development and progression of PCa is unclear. The present study aims to determine the density of GDF-15+ cells and immune cells (M1-/M2 macrophages [MΦ], lymphocytes) in PCa of different Gleason scores (GS) compared to BPH. Immunohistochemistry and double immunofluorescence were performed on paraffin-embedded human PCa and BPH biopsies with antibodies directed against GDF-15, CD68 (M1 MΦ), CD163 (M2 MΦ), CD4, CD8, CD19 (T /B lymphocytes), or PD-L1. PGP9.5 served as a marker for innervation and neuroendocrine cells. GDF-15+ cell density was higher in all GS than in BPH. CD68+ MΦ density in GS9 and CD163+ MΦ exceeded that in BPH. GDF-15+ cell density correlated significantly positively with CD68+ or CD163+ MΦ density in extratumoral areas. Double immunoreactive GDF-15+/CD68+ cells were found as transepithelial migrating MΦ. Stromal CD68+ MΦ lacked GDF-15+. The area of PGP9.5+ innervation was higher in GS9 than in BPH. PGP9.5+ cells, occasionally copositive for GDF-15+, also occurred in the glandular epithelium. In GS6, but not in BPH, GDF-15+, PD-L1+, and CD68+ cells were found in epithelium within luminal excrescences. The degree of extra-/intra-tumoral GDF-15 increases in M1/M2Φ is proposed to be useful to stratify progredient malignancy of PCa. GDF-15 is a potential target for anti-tumor therapy.

Comprehensive Analysis of m5C Methylation Regulatory Genes and Tumor Microenvironment in Prostate Cancer

Background

5-Methylcytidine (m5C) methylation is an emerging epigenetic modification in recent years, which is associated with the development and progression of various cancers. However, the prognostic value of m5C regulatory genes and the correlation between m5C methylation and the tumor microenvironment (TME) in prostate cancer remain unknown.

Methods

In the current study, the genetic and transcriptional alterations and prognostic value of m5C regulatory genes were investigated in The Cancer Genome Atlas and Gene Expression Omnibus datasets. Then, an m5C prognostic model was established by LASSO Cox regression analysis. Gene set variation analyses (GSVA), gene set enrichment analysis (GSEA), clinical relevance, and TME analyses were conducted to explain the biological functions and quantify the TME scores between high-risk and low-risk subgroups. m5C regulatory gene clusters and m5C immune subtypes were identified using consensus unsupervised clustering analysis. The Cell-type Identification By Estimating Relative Subsets of RNA Transcripts algorithm was used to calculate the contents of immune cells.

Results

TET3 was upregulated at transcriptional levels in PCa compared with normal tissues, and a high TET3 expression was associated with poor prognosis. An m5C prognostic model consisting of 3 genes (NSUN2, TET3, and YBX1) was developed and a nomogram was constructed for improving the clinical applicability of the model. Functional analysis revealed the enrichment of pathways and the biological processes associated with RNA regulation and immune function. Significant differences were also found in the expression levels of m5C regulatory genes, TME scores, and immune cell infiltration levels between different risk subgroups. We identified two distinct m5C gene clusters and found their correlation with patient prognosis and immune cell infiltration characteristics. Naive B cells, CD8+ T cells, M1 macrophages and M2 macrophages were obtained and 2 m5C immune subtypes were identified. CTLA4, NSUN6, TET1, and TET3 were differentially expressed between immune subtypes. The expression of CTLA4 was found to be correlated with the degree of immune cell infiltration.

Conclusions

Our comprehensive analysis of m5C regulatory genes in PCa demonstrated their potential roles in the prognosis, clinical features, and TME. These findings may improve our understanding of m5C regulatory genes in the tumor biology of PCa.

Macrophage inhibitory cytokine-1 in cancer: Beyond the cellular phenotype

Despite technological advances in diagnostic abilities and improved treatment methods, the burden of cancers remains high, leading to significant morbidity and mortality. One primary reason is that cancer cell secretory factors modulate the tumor microenvironment, supporting tumor growth and circumvents anticancer activities of conventional therapies. Macrophage inhibitory cytokine-1 (MIC-1) is a pleiotropic cytokine elevated in various cancers. MIC-1 regulates various cancer hallmarks, including sustained proliferation, tumor-promoting inflammation, avoiding immune destruction, inducing invasion, metastasis, angiogenesis, and resisting cell death. Despite these facts, the molecular regulation and downstream signaling of MIC-1 in cancer remain elusive, partly because its receptor (GFRAL) was unknown until recently. Binding of MIC-1 to GFRAL recruits the coreceptor tyrosine kinase RET to execute its downstream signaling. So far, studies have shown that GFRAL expression is restricted to the brain stem and is responsible for MIC-1/GFRAL/RET-mediated metabolic disorders. Nevertheless, abundant levels of MIC-1 expression have been reported in all cancer types and have been proposed as a surrogate biomarker. Given the ubiquitous expression of MIC-1 in cancers, it is crucial to understand both upstream regulation and downstream MIC-1/GFRAL/RET signaling in cancer hallmark traits.

Immune cell infiltrates and prognosis in localized prostate cancer†

Multiple lines of evidence indicate that quantification of immune cell infiltrates in primary prostate cancer can predict outcomes after radical prostatectomy, including biochemical recurrence, metastasis, and death from prostate cancer. In a recent issue of The Journal of Pathology, Andersen et al explored the predictive value of cancer tissue infiltration of seven immune cell types (mast cells, M1 macrophages, M2 macrophages, B cells, T helper cells, cytotoxic T cells, and regulatory T cells) in association with biochemical recurrence after radical prostatectomy. In addition to reporting a potential association between cancer-infiltrating regulatory T cells and M1 and M2 macrophages and biochemical recurrence, the study also highlighted the use of multiplex digital pathology analyses to assess adverse predictors of prostate cancer outcomes. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Growth and differentiation factor 15 and NF-κB expression in benign prostatic biopsies and risk of subsequent prostate cancer detection

Growth and differentiation factor 15 (GDF‐15), also known as macrophage inhibitory cytokine 1 (MIC‐1), may act as both a tumor suppressor and promotor and, by regulating NF‐κB and macrophage signaling, promote early prostate carcinogenesis. To determine whether expression of these two inflammation‐related proteins affect prostate cancer susceptibility, dual immunostaining of benign prostate biopsies for GDF‐15 and NF‐κB was done in a study of 503 case‐control pairs matched on date, age, and race, nested within a historical cohort of 10,478 men. GDF‐15 and NF‐κB expression levels were positively correlated (r = 0.39; p < 0.0001), and both were significantly lower in African American (AA) compared with White men. In adjusted models that included both markers, the odds ratio (OR) for NF‐κB expression was statistically significant, OR =0.87; p = 0.03; 95% confidence interval (CI) =0.77–0.99, while GDF‐15 expression was associated with a nominally increased risk, OR =1.06; p = 0.27; 95% CI =0.96–1.17. When modeling expression levels by quartiles, the highest quartile of NF‐κB expression was associated with almost a fifty percent reduction in prostate cancer risk (OR =0.51; p = 0.03; 95% CI =0.29–0.92). In stratified models, NF‐κB had the strongest negative association with prostate cancer in non‐aggressive cases (p = 0.03), older men (p = 0.03), and in case‐control pairs with longer follow‐up (p = 0.02). Risk associated with GDF‐15 expression was best fit using nonlinear regression modeling where both first (p = 0.02) and second (p = 0.03) order GDF‐15 risk terms were associated with significantly increased risk. This modeling approach also revealed significantly increased risk associated with GDF‐15 expression for subsamples defined by AA race, aggressive disease, younger age, and in case‐control pairs with longer follow‐up. Therefore, although positively correlated in benign prostatic biopsies, NF‐κB and GDF‐15 expression appear to exert opposite effects on risk of prostate tumor development.