ACK1-AR and AR-HOXB13 signaling axes: epigenetic regulation of lethal prostate cancers

Epigenetic underpinnings of tumor-immune dynamics in prostate cancer immune suppression

Prostate cancer (PC) is immunosuppressive and refractory to immunotherapy. Infiltration of myeloid-derived suppressor cells (MDSCs) and senescent-like neutrophils and T cell exhaustion are observed in the tumor microenvironment (TME) following androgen receptor (AR) antagonism with antiandrogens or androgen ablation. De novo post-translational acetylation of the AR, HOXB13, and H2A at K609, K13, and K130, respectively, and phosphorylation of H4 at Y88 have emerged as key epigenetic modifications associated with castration-resistant PC (CRPC). The resulting chromatin changes are integrated into cellular processes via phosphorylation of the AR, ACK1, ATPF1A, and SREBP1 at Y267, Y284, Y243/Y246, and Y673/Y951, respectively. In this review, we discuss how these de novo epigenetic alterations drive resistance and how efforts aimed at targeting these regulators may overcome immune suppression observed in PC.

Symptomatic Benign Prostatic Hyperplasia with Suppressed Epigenetic Regulator HOXB13 Shows a Lower Incidence of Prostate Cancer Development

Our objective was to identify variations in gene expression that could help elucidate the pathways for the development of prostate cancer (PCa) in men with Benign Prostatic Hyperplasia (BPH). We included 98 men with BPH, a positive prostate MRI (Prostate Imaging Reporting and Data System; PIRADS ≥ 4), and a negative biopsy from November 2014 to January 2018. RNA sequencing (RNA-Seq) was performed on tissue cores from the MRI lesion and a geographically distant region (two regions per patient). All patients were followed for at least three years to identify who went on to develop PCa. We compared the gene expressions of those who did not develop PCa ("BPH-only") vs. those who did ("BPH/PCa"). Then, we identified the subset of men with BPH who had the highest American Urological Association (AUA) symptom scores ("symptomatic BPH") and compared their gene expression to the BPH/PCa group. At a median follow-up of 47.5 months, 15 men had developed PCa while 83 did not. We compared gene expressions of 14 men with symptomatic BPH (AUAss ≥ 18) vs. 15 with BPH/PCa. We found two clusters of genes, suggesting the two groups had distinctive molecular features. Differential analysis revealed genes that were upregulated in BPH-only and downregulated in BPH/PCa, and vice versa. Symptomatic BPH men had upregulation of T-cell activation markers (TCR, CD3, ZAP70, IL-2 and IFN-γ and chemokine receptors, CXCL9/10) expression. In contrast, men with BPH/PCa had upregulation of NKX3-1 and HOXB13 transcription factors associated with luminal epithelial progenitors but depleted of immune cells, suggesting a cell-autonomous role in immune evasion. Symptomatic BPH with immune-enriched landscapes may support anti-tumor immunity. RNA sequencing of benign prostate biopsy tissue showing upregulation of NKX3-1 and HOXB13 with the absence of T-cells might help in identifying men at higher risk of future PCa development, which may be useful in determining ongoing PCa screening.

Characterization of HOXB13 expression patterns in localized and metastatic castration-resistant prostate cancer

HOXB13 is a key lineage homeobox transcription factor that plays a critical role in the differentiation of the prostate gland. Several studies have suggested that HOXB13 alterations may be involved in prostate cancer development and progression. Despite its potential biological relevance, little is known about the expression of HOXB13 across the disease spectrum of prostate cancer. To this end, we validated a HOXB13 antibody using genetic controls and investigated HOXB13 protein expression in murine and human developing prostates, localized prostate cancers, and metastatic castration-resistant prostate cancers. We observed that HOXB13 expression increases during later stages of murine prostate development. All localized prostate cancers showed HOXB13 protein expression. Interestingly, lower HOXB13 expression levels were observed in higher-grade tumors, although no significant association between HOXB13 expression and recurrence or disease-specific survival was found. In advanced metastatic prostate cancers, HOXB13 expression was retained in the majority of tumors. While we observed lower levels of HOXB13 protein and mRNA levels in tumors with evidence of lineage plasticity, 84% of androgen receptor-negative castration-resistant prostate cancers and neuroendocrine prostate cancers (NEPCs) retained detectable levels of HOXB13. Notably, the reduced expression observed in NEPCs was associated with a gain of HOXB13 gene body CpG methylation. In comparison to the commonly used prostate lineage marker NKX3.1, HOXB13 showed greater sensitivity in detecting advanced metastatic prostate cancers. Additionally, in a cohort of 837 patients, 383 with prostatic and 454 with non-prostatic tumors, we found that HOXB13 immunohistochemistry had a 97% sensitivity and 99% specificity for prostatic origin. Taken together, our studies provide valuable insight into the expression pattern of HOXB13 during prostate development and cancer progression. Furthermore, our findings support the utility of HOXB13 as a diagnostic biomarker for prostate cancer, particularly to confirm the prostatic origin of advanced metastatic castration-resistant tumors. © 2023 The Pathological Society of Great Britain and Ireland.

Current therapy and drug resistance in metastatic castration-resistant prostate cancer

Castration-resistant prostate cancer (CRPC), especially metastatic castration-resistant prostate cancer (mCRPC) is one of the most prevalent malignancies and main cause of cancer-related death among men in the world. In addition, it is very difficult for clinical treatment because of the natural or acquired drug resistance of CRPC. Mechanisms of drug resistance are extremely complicated and how to overcome it remains an urgent clinical problem to be solved. Thus, a comprehensive and thorough understanding for mechanisms of drug resistance in mCRPC is indispensable to develop novel and better therapeutic strategies. In this review, we aim to review new insight of the treatment of mCRPC and elucidate mechanisms governing resistance to new drugs: taxanes, androgen receptor signaling inhibitors (ARSIs) and poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). Most importantly, in order to improve efficacy of these drugs, strategies of overcoming drug resistance are also discussed based on their mechanisms respectively.

Domain Architecture of the Nonreceptor Tyrosine Kinase Ack1

The nonreceptor tyrosine kinase (NRTK) Ack1 comprises a distinct arrangement of non-catalytic modules. Its SH3 domain has a C-terminal to the kinase domain (SH1), in contrast to the typical SH3-SH2-SH1 layout in NRTKs. The Ack1 is the only protein that shares a region of high homology to the tumor suppressor protein Mig6, a modulator of EGFR. The vertebrate Acks make up the only tyrosine kinase (TK) family known to carry a UBA domain. The GTPase binding and SAM domains are also uncommon in the NRTKs. In addition to being a downstream effector of receptor tyrosine kinases (RTKs) and integrins, Ack1 can act as an epigenetic regulator, modulate the degradation of the epidermal growth factor receptor (EGFR), confer drug resistance, and mediate the progression of hormone-sensitive tumors. In this review, we discuss the domain architecture of Ack1 in relation to other protein kinases that possess such defined regulatory domains.

HSPB8 facilitates prostate cancer progression via activating the JAK/STAT3 signaling pathway

Prostate cancer (PC) is a clinically and biologically heterogeneous disease that lacks effective treatment. Heat shock protein B8 (HSPB8) is an important factor in the progression of various types of cancer. However, the clinical significance and biological role of HSPB8 in PC are still unclear. In this study, we determined HSPB8 expression in PC tissues by immunohistochemical staining and explored the in vitro functions of HSPB8 using HSPB8 knockdown DU145 and LNcap PC cell lines. The in vivo effect of HSPB8 was explored by a subcutaneous xenograft mice model. The human phospho-kinase array and signal transducer and activator of transcription (STAT) 3 activator were utilized to explore the potential mechanism of HSPB8-induced PC progression. As a result, we found that HSPB8 was abundantly expressed in PC tissues and cell lines. HSPB8 knockdown inhibited cell proliferation and migration, promoted apoptosis and cycle repression, as well as weakened tumorigenesis ability. Mechanistically, we demonstrated that HSPB8 facilitates the malignant phenotypes of PC by activating the Janus kinase/STAT3 signaling pathway. These results proposed that HSPB8 seems to be an attractive therapeutic target for PC patients.

Pharmacological Modulation of the Crosstalk between Aberrant Janus Kinase Signaling and Epigenetic Modifiers of the Histone Deacetylase Family to Treat Cancer

Hyperactivated Janus kinase (JAK) signaling is an appreciated drug target in human cancers. Numerous mutant JAK molecules as well as inherent and acquired drug resistance mechanisms limit the efficacy of JAK inhibitors (JAKi). There is accumulating evidence that epigenetic mechanisms control JAK-dependent signaling cascades. Like JAKs, epigenetic modifiers of the histone deacetylase (HDAC) family regulate the growth and development of cells and are often dysregulated in cancer cells. The notion that inhibitors of histone deacetylases (HDACi) abrogate oncogenic JAK-dependent signaling cascades illustrates an intricate crosstalk between JAKs and HDACs. Here, we summarize how structurally divergent, broad-acting as well as isoenzyme-specific HDACi, hybrid fusion pharmacophores containing JAKi and HDACi, and proteolysis targeting chimeras for JAKs inactivate the four JAK proteins JAK1, JAK2, JAK3, and tyrosine kinase-2. These agents suppress aberrant JAK activity through specific transcription-dependent processes and mechanisms that alter the phosphorylation and stability of JAKs. Pharmacological inhibition of HDACs abrogates allosteric activation of JAKs, overcomes limitations of ATP-competitive type 1 and type 2 JAKi, and interacts favorably with JAKi. Since such findings were collected in cultured cells, experimental animals, and cancer patients, we condense preclinical and translational relevance. We also discuss how future research on acetylation-dependent mechanisms that regulate JAKs might allow the rational design of improved treatments for cancer patients. SIGNIFICANCE STATEMENT: Reversible lysine-ɛ-N acetylation and deacetylation cycles control phosphorylation-dependent Janus kinase-signal transducer and activator of transcription signaling. The intricate crosstalk between these fundamental molecular mechanisms provides opportunities for pharmacological intervention strategies with modern small molecule inhibitors. This could help patients suffering from cancer.

HSPB8 counteracts tumor activity of BRAF- and NRAS-mutant melanoma cells by modulation of RAS-prenylation and autophagy

Cutaneous melanoma is one of the most aggressive and lethal forms of skin cancer. Some specific driver mutations have been described in multiple oncogenes including BRAF and NRAS that are mutated in 60-70% and 15-20% of melanoma, respectively. The aim of this study was to evaluate the role of Small Heat Shock Protein B8 (HSPB8) on cell growth and migration of both BLM (BRAF^wt/NRAS^Q61R) and A375 (BRAF^V600E/NRAS^wt) human melanoma cell lines. HSPB8 is a member of the HSPB family of chaperones involved in protein quality control (PQC) system and contributes to chaperone assisted selective autophagy (CASA) as well as in the regulation of mitotic spindle. In cancer, HSPB8 has anti- or pro-tumoral action depending on tumor type. In melanoma cell lines characterized by low HSPB8 levels, we demonstrated that the restoration of HSPB8 expression causes cell growth arrest, reversion of EMT (Epithelial-Mesenchymal Transition)-like phenotype switching and antimigratory effect, independently from the cell mutational status. We demonstrated that HSPB8 regulates the levels of the active prenylated form of NRAS in NRAS-mutant and NRAS-wild-type melanoma cell lines. Consequently, the inhibition of NRAS impairs the activation of Akt/mTOR pathway inducing autophagy activation. Autophagy can play a dual role in regulating cell death and survival. We have therefore demonstrated that HSPB8-induced autophagy is a crucial event that counteracts cell growth in melanoma. Collectively, our results suggest that HSPB8 has an antitumoral action in melanoma cells characterized by BRAF and NRAS mutations.

Acetylated HOXB13 Regulated Super Enhancer Genes Define Therapeutic Vulnerabilities of Castration-Resistant Prostate Cancer

PURPOSE

Androgen receptor (AR) antagonism is exacerbated by HOXB13 in castration-resistant prostate cancers (CRPC). However, it is unclear when and how HOXB13 primes CRPCs for AR antagonism. By mass-spectrometry analysis of CRPC extract, we uncovered a novel lysine 13 (K13) acetylation in HOXB13 mediated by CBP/p300. To determine whether acetylated K13-HOXB13 is a clinical biomarker of CRPC development, we characterized its role in prostate cancer biology.

EXPERIMENTAL DESIGN

We identified tumor-specific acK13-HOXB13 signal enriched super enhancer (SE)-regulated targets. We analyzed the effect of loss of HOXB13K13-acetylation on chromatin binding, SE proximal target gene expression, self-renewal, enzalutamide sensitivity, and CRPC tumor growth by employing isogenic parental and HOXB13K13A mutants. Finally, using primary human prostate organoids, we evaluated whether inhibiting an acK13-HOXB13 target, ACK1, with a selective inhibitor (R)-9b is superior to AR antagonists in inhibiting CRPC growth.

RESULTS

acK13-HOXB13 promotes increased expression of lineage (AR, HOXB13), prostate cancer diagnostic (FOLH1), CRPC-promoting (ACK1), and angiogenesis (VEGFA, Angiopoietins) genes early in prostate cancer development by establishing tumor-specific SEs. acK13-HOXB13 recruitment to key SE-regulated targets is insensitive to enzalutamide. ACK1 expression is significantly reduced in the loss of function HOXB13K13A mutant CRPCs. Consequently, HOXB13K13A mutants display reduced self-renewal, increased sensitivity to enzalutamide, and impaired xenograft tumor growth. Primary human prostate tumor organoids expressing HOXB13 are significantly resistant to AR antagonists but sensitive to (R)-9b.

CONCLUSIONS

In summary, acetylated HOXB13 is a biomarker of clinically significant prostate cancer. Importantly, PSMA-targeting agents and (R)-9b could be new therapeutic modalities to target HOXB13-ACK1 axis regulated prostate cancers.

Resistance to prostate cancer treatments

A review of the current treatment options for prostate cancer and the formation of resistance to these regimens has been compiled including primary, acquired, and cross-resistance. The diversification of the pathways involved and the escape routes the tumor is utilizing have been addressed. Whereas early stages of tumor can be cured, there is no treatment available after a point of no return has been reached, leaving palliative treatment as the only option. The major reasons for this outcome are the heterogeneity of tumors, both inter- and intra-individually and the nearly endless number of escape routes, which the tumor can select to overcome the effects of treatment. This means that more focus should be applied to the individualization of both diagnosis and therapy of prostate cancer. In addition to current treatment options, novel drugs and ongoing clinical trials have been addressed in this review.

Drug resistance in metastatic castration-resistant prostate cancer: an update on the status quo

Prostate cancer (PCa) is a leading cause of cancer-related morbidity and mortality in men globally. Despite improvements in the diagnosis and treatment of PCa, a significant proportion of patients with high-risk localized disease and all patients with advanced disease at diagnosis will experience progression to metastatic castration-resistant prostate cancer (mCRPC). Multiple drugs are now approved as the standard of care treatments for patients with mCRPC that have been shown to prolong survival. Although the majority of patients will respond initially, primary and secondary resistance to these therapies make mCRPC an incurable disease. Several molecular mechanisms underlie the development of mCRPC, with the androgen receptor (AR) axis being the main driver as well as the key drug target. Understanding resistance mechanisms is crucial for discovering novel therapeutic strategies to delay or reverse the progression of the disease. In this review, we address the diverse mechanisms of drug resistance in mCRPC. In addition, we shed light on emerging targeted therapies currently being tested in clinical trials with promising potential to overcome mCRPC-drug resistance.

Chronologically modified androgen receptor in recurrent castration-resistant prostate cancer and its therapeutic targeting

Resistance to second-generation androgen receptor (AR) antagonists such as enzalutamide is an inevitable consequence in patients with castration-resistant prostate cancer (CRPC). There are no effective therapeutic options for this recurrent disease. The expression of truncated AR variant 7 (AR-V7) has been suggested to be one mechanism of resistance; however, its low frequency in patients with CRPC does not explain the almost universal acquisition of resistance. We noted that the ability of AR to translocate to nucleus in an enzalutamide-rich environment opens up the possibility of a posttranslational modification in AR that is refractory to enzalutamide binding. Chemical proteomics in enzalutamide-resistant CRPC cells revealed acetylation at Lys609 in the zinc finger DNA binding domain of AR (acK609-AR) that not only allowed AR translocation but also galvanized a distinct global transcription program, conferring enzalutamide insensitivity. Mechanistically, acK609-AR was recruited to the AR and ACK1/TNK2 enhancers, up-regulating their transcription. ACK1 kinase-mediated AR Y267 phosphorylation was a prerequisite for AR K609 acetylation, which spawned positive feedback loops at both the transcriptional and posttranslational level that regenerated and sustained high AR and ACK1 expression. Consistent with these findings, oral and subcutaneous treatment with ACK1 small-molecule inhibitor, (R)-9b, not only curbed AR Y267 phosphorylation and subsequent K609 acetylation but also compromised enzalutamide-resistant CRPC xenograft tumor growth in mice. Overall, these data uncover chronological modification events in AR that allows prostate cancer to evolve through progressive stages to reach the resilient recurrent CRPC stage, opening up a therapeutic vulnerability.

From Omics to Multi-Omics Approaches for In-Depth Analysis of the Molecular Mechanisms of Prostate Cancer

Cancer arises following alterations at different cellular levels, including genetic and epigenetic modifications, transcription and translation dysregulation, as well as metabolic variations. High-throughput omics technologies that allow one to identify and quantify processes involved in these changes are now available and have been instrumental in generating a wealth of steadily increasing data from patient tumors, liquid biopsies, and from tumor models. Extensive investigation and integration of these data have led to new biological insights into the origin and development of multiple cancer types and helped to unravel the molecular networks underlying this complex pathology. The comprehensive and quantitative analysis of a molecule class in a biological sample is named omics and large-scale omics studies addressing different prostate cancer stages have been performed in recent years. Prostate tumors represent the second leading cancer type and a prevalent cause of cancer death in men worldwide. It is a very heterogenous disease so that evaluating inter- and intra-tumor differences will be essential for a precise insight into disease development and plasticity, but also for the development of personalized therapies. There is ample evidence for the key role of the androgen receptor, a steroid hormone-activated transcription factor, in driving early and late stages of the disease, and this led to the development and approval of drugs addressing diverse targets along this pathway. Early genomic and transcriptomic studies have allowed one to determine the genes involved in prostate cancer and regulated by androgen signaling or other tumor-relevant signaling pathways. More recently, they have been supplemented by epigenomic, cistromic, proteomic and metabolomic analyses, thus, increasing our knowledge on the intricate mechanisms involved, the various levels of regulation and their interplay. The comprehensive investigation of these omics approaches and their integration into multi-omics analyses have led to a much deeper understanding of the molecular pathways involved in prostate cancer progression, and in response and resistance to therapies. This brings the hope that novel vulnerabilities will be identified, that existing therapies will be more beneficial by targeting the patient population likely to respond best, and that bespoke treatments with increased efficacy will be available soon.

Baseline Plasma Tumor DNA (ctDNA) Correlates with PSA Kinetics in Metastatic Castration-Resistant Prostate Cancer (mCRPC) Treated with Abiraterone or Enzalutamide

Background: Baseline high circulating tumor DNA (ctDNA) fraction in plasma and androgen receptor (AR) copy number (CN) gain identify mCRPC patients with worse outcomes. This study aimed to assess if ctDNA associates with PSA kinetics. Methods: In this prospective biomarker study, we evaluate ctDNA fraction and AR CN from plasma samples. We divided patients into high and low ctDNA level and in AR gain and AR normal. Results: 220 baseline samples were collected from mCRPC treated with abiraterone (n = 140) or enzalutamide (n = 80). A lower rate of PSA decline ≥ 50% was observed in patients with high ctDNA (p = 0.017) and AR gain (p = 0.0003). Combining ctDNA fraction and AR CN, we found a different median PSA progression-free survival (PFS) among four groups: (1) low ctDNA/AR normal, (2) high ctDNA/AR normal, (3) low ctDNA/AR gain, and (4) high ctDNA/AR gain (11.4 vs. 5.0 vs. 4.8 vs. 3.7 months, p < 0.0001). In a multivariable analysis, high ctDNA, AR gain, PSA DT, PSA DT velocity remained independent predictors of PSA PFS. Conclusions: Elevated ctDNA levels and AR gain are negatively and independently correlated with PSA kinetics in mCRPC men treated with abiraterone or enzalutamide.

Targeting Protein Kinases and Epigenetic Control as Combinatorial Therapy Options for Advanced Prostate Cancer Treatment

Prostate cancer (PC), the fifth leading cause of cancer-related mortality worldwide, is known as metastatic bone cancer when it spreads to the bone. Although there is still no effective treatment for advanced/metastatic PC, awareness of the molecular events that contribute to PC progression has opened up opportunities and raised hopes for the development of new treatment strategies. Androgen deprivation and androgen-receptor-targeting therapies are two gold standard treatments for metastatic PC. However, acquired resistance to these treatments is a crucial challenge. Due to the role of protein kinases (PKs) in the growth, proliferation, and metastases of prostatic tumors, combinatorial therapy by PK inhibitors may help pave the way for metastatic PC treatment. Additionally, PC is known to have epigenetic involvement. Thus, understanding epigenetic pathways can help adopt another combinatorial treatment strategy. In this study, we reviewed the PKs that promote PC to advanced stages. We also summarized some PK inhibitors that may be used to treat advanced PC and we discussed the importance of epigenetic control in this cancer. We hope the information presented in this article will contribute to finding an effective treatment for the management of advanced PC.

Androgen Receptor-Dependent Mechanisms Mediating Drug Resistance in Prostate Cancer

Androgen receptor (AR) is a main driver of prostate cancer (PCa) growth and progression as well as the key drug target. Appropriate PCa treatments differ depending on the stage of cancer at diagnosis. Although androgen deprivation therapy (ADT) of PCa is initially effective, eventually tumors develop resistance to the drug within 2-3 years of treatment onset leading to castration resistant PCa (CRPC). Castration resistance is usually mediated by reactivation of AR signaling. Eventually, PCa develops additional resistance towards treatment with AR antagonists that occur regularly, also mostly due to bypass mechanisms that activate AR signaling. This tumor evolution with selection upon therapy is presumably based on a high degree of tumor heterogenicity and plasticity that allows PCa cells to proliferate and develop adaptive signaling to the treatment and evolve pathways in therapy resistance, including resistance to chemotherapy. The therapy-resistant PCa phenotype is associated with more aggressiveness and increased metastatic ability. By far, drug resistance remains a major cause of PCa treatment failure and lethality. In this review, various acquired and intrinsic mechanisms that are AR‑dependent and contribute to PCa drug resistance will be discussed.

The Role of HSPB8, a Component of the Chaperone-Assisted Selective Autophagy Machinery, in Cancer

The cellular response to cancer-induced stress is one of the major aspects regulating cancer development and progression. The Heat Shock Protein B8 (HSPB8) is a small chaperone involved in chaperone-assisted selective autophagy (CASA). CASA promotes the selective degradation of proteins to counteract cell stress such as tumor-induced stress. HSPB8 is also involved in (i) the cell division machinery regulating chromosome segregation and cell cycle arrest in the G0/G1 phase and (ii) inflammation regulating dendritic cell maturation and cytokine production. HSPB8 expression and role are tumor-specific, showing a dual and opposite role. Interestingly, HSPB8 may be involved in the acquisition of chemoresistance to drugs. Despite the fact the mechanisms of HSPB8-mediated CASA activation in tumors need further studies, HSPB8 could represent an important factor in cancer induction and progression and it may be a potential target for anticancer treatment in specific types of cancer. In this review, we will discuss the molecular mechanism underlying HSPB8 roles in normal and cancer conditions. The basic mechanisms involved in anti- and pro-tumoral activities of HSPB8 are deeply discussed together with the pathways that modulate HSPB8 expression, in order to outline molecules with a beneficial effect for cancer cell growth, migration, and death.

Epigenetic reprogramming during prostate cancer progression: A perspective from development

Conrad Waddington's theory of epigenetic landscape epitomize the process of cell fate and cellular decision-making during development. Wherein the epigenetic code maintains patterns of gene expression in pluripotent and differentiated cellular states during embryonic development and differentiation. Over the years disruption or reprogramming of the epigenetic landscape has been extensively studied in the course of cancer progression. Cellular dedifferentiation being a key hallmark of cancer allow us to take cues from the biological processes involved during development. Here, we discuss the role of epigenetic landscape and its modifiers in cell-fate determination, differentiation and prostate cancer progression. Lately, the emergence of RNA-modifications has also furthered our understanding of epigenetics in cancer. The overview of the epigenetic code regulating androgen signalling, and progression to aggressive neuroendocrine stage of PCa reinforces its gene regulatory functions during the development of prostate gland as well as cancer progression. Additionally, we also highlight the clinical implications of cancer cell epigenome, and discuss the recent advancements in the therapeutic strategies targeting the advanced stage disease.

HOXB13 and TFF3 can contribute to the prognostic stratification of prostate adenocarcinoma

Homeobox B13 (HOXB13) and trefoil factor 3 (TFF3) are novel candidates for the classification of prostate cancer (PC) in molecular subtypes that could predict the clinical evolution of patients. The aim of our study was to analyze the possible associations between HOXB13 and TFF3 immunohistochemical (IHC) expression in sporadic prostate adenocarcinoma (PAC), the potential prognostic value in relation to the classical clinico-pathological parameters, as well as their role in defining distinct molecular subtypes of this malignancy. The study group comprised 105 patients diagnosed with PAC who underwent radical prostatectomy. IHC exam was performed using anti-HOXB13 and anti-TFF3 antibodies and a scoring system that permit the separation of the cases into two subgroups, with low and high immunoexpression, respectively. The statistical analysis evaluated the relationship between the two immunomarkers and clinico-pathological parameters. The Kaplan-Meier curves and log-rank Mantel-Cox test were used for assessing the prostate-specific antigen (PSA)-progression free survival. Four subgroups of PAC were defined based on the IHC overexpression and low immunoexpression of HOXB13 and TFF3. High HOXB13 and TFF3 immunoexpression was commonly identified in cases characterized by a Gleason score over 7, a G4 or G5 dominant pattern, a grade group of 3 or 4 and a preoperatory PSA serum level over 20 ng/mL. HOXB13 overexpression was also associated with pathological tumor-node-metastasis (pTNM) stage. The subgroup with both low HOXB13 and TFF3 immunoexpression had the highest PSA-progression free interval, whereas the subgroup with high HOXB13 immunoexpression and low TFF3 immunoexpression presented the lowest rate, but no statistically significant differences were registered. Our results sustain the role of HOXB13 and TFF3 in the stratification of PAC. Further investigations in larger cohorts are imposed to validate the clinical significance of these subgroups in the diagnostic and prognostic of PAC.