Differential response to neoadjuvant hormonal therapy in prostate cancer: Predictive morphological parameters and molecular markers

The Oncological and Functional Prognostic Value of Unconventional Histology of Prostate Cancer in Localized Disease Treated with Robotic Radical Prostatectomy: An International Multicenter 5-Year Cohort Study

BACKGROUND AND OBJECTIVE

The impact of prostate cancer of unconventional histology (UH) on oncological and functional outcomes after robot-assisted radical prostatectomy (RARP) and adjuvant radiotherapy (aRT) receipt is unclear. We compared the impact of cribriform pattern (CP), ductal adenocarcinoma (DAC), and intraductal carcinoma (IDC) in comparison to pure adenocarcinoma (AC) on short- to mid-term oncological and functional results and receipt of aRT after RARP.

METHODS

We retrospectively collected data for a large international cohort of men with localized prostate cancer treated with RARP between 2016 and 2020. The primary outcomes were biochemical recurrence (BCR)-free survival, erectile and continence function. aRT receipt was a secondary outcome. Kaplan-Meier survival and Cox regression analyses were performed.

KEY FINDINGS AND LIMITATIONS

A total of 3935 patients were included. At median follow-up of 2.8 yr, the rates for BCR incidence (AC 10.7% vs IDC 17%; p < 0.001) and aRT receipt (AC 4.5% vs DAC 6.3% [p = 0.003] vs IDC 11.2% [p < 0.001]) were higher with UH. The 5-yr BCR-free survival rate was significantly poorer for UH groups, with hazard ratios of 1.67 (95% confidence interval [CI] 1.16-2.40; p = 0.005) for DAC, 5.22 (95% CI 3.41-8.01; p < 0.001) for IDC, and 3.45 (95% CI 2.29-5.20; p < 0.001) for CP in comparison to AC. Logistic regression analysis revealed that the presence of UH doubled the risk of new-onset erectile dysfunction at 1 yr, in comparison to AC (grade group 1-3), with hazard ratios of 2.13 (p < 0.001) for DAC, 2.14 (p < 0.001) for IDC, and 2.01 (p = 0.011) for CP. Moreover, CP, but not IDC or DAC, was associated with a significantly higher risk of incontinence (odds ratio 1.97; p < 0.001). The study is limited by the lack of central histopathological review and relatively short follow-up.

CONCLUSIONS AND CLINICAL IMPLICATIONS

In a large cohort, UH presence was associated with worse short- to mid-term oncological outcomes after RARP. IDC independently predicted a higher rate of aRT receipt. At 1-yr follow-up after RP, patients with UH had three times higher risk of erectile dysfunction post RARP; CP was associated with a twofold higher incontinence rate.

PATIENT SUMMARY

Among patients with prostate cancer who undergo robot-assisted surgery to remove the prostate, those with less common types of prostate cancer have worse results for cancer control, erection, and urinary continence and a higher probability of receiving additional radiotherapy after surgery.

The role of androgen deprivation therapy prior to radical prostatectomy in high-risk prostate cancer: a systematic review

INTRODUCTION

Patients with high-risk prostate cancer (HRPCa) are prone to have worse pathological features, resulting in early biochemical recurrence after radical prostatectomy (RP). There is an urgent need to develop novel treatment strategies for this group of patients to optimize their outcomes. The purpose of this study is to perform a systematic review of the role of neoadjuvant hormonal therapy (NHT) followed by RP in HRPCa patients.

EVIDENCE ACQUISITION

We performed a systematic review of the following databases, MEDLINE (PubMed), EMBASE, Cochrane Library, and clinical Trial.gov; between January 2007 and August 2023, following the PRISMA guidelines.

EVIDENCE SYNTHESIS

After screening and deduplication, we included ten studies from an initial pool of 1275. The risk of bias was low in observational studies but ranged from moderate to low in controlled trials. Five studies utilized traditional androgen deprivation treatments (ADT), revealing favorable pathological outcomes but inconsistency in evaluating oncological results. Additionally, four studies focused on RP combined with androgen receptor pathway inhibitors (ARPIs) in the NHT setting, all showing primarily positive pathological outcome, with no clear evidence of an oncological benefit. Limited long-term follow-up data and a shortage of randomized controlled trials were evident among all the studies included in this review, regardless of the type of hormonal treatment used.

CONCLUSIONS

Different hormonal treatments, including traditional ADT and ARPIs, yield positive pathology outcomes. Oncological evidence remains limited, echoing older findings predating ARPIs. Definitive conclusions require longer follow-ups and precise patient selection. Currently, insufficient evidence support ARPIs' superiority over conventional therapy before RP.

Lymphotropic Pattern of Prostate-specific Membrane Antigen-detected Metastases Among Biochemically Recurrent Radical Prostatectomy Patients with Cribriform Disease

BACKGROUND

Cribriform morphology portends worse oncologic outcomes, and has unique cellular intrinsic pathway alterations and tumor microenvironments that may impact metastatic spread patterns.

OBJECTIVE

To determine whether the presence of cribriform morphology in prostatectomy specimens of patients with biochemical recurrence after radical prostatectomy (RP) is associated with the presence of metastasis on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and a distinct pattern of spread.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional analysis was conducted of all prostate cancer patients with biochemical recurrence after RP undergoing 18F-DCFPyL-PET/CT between December 2018 and February 2021 at the Princess Margaret Cancer Centre.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Outcomes were presence of any metastasis in the overall cohort and lymphatic versus bone/visceral metastases among patients with metastatic disease. The associations between the presence of intraductal (IDC) and/or invasive cribriform (ICC) carcinoma on the RP specimen and study outcomes were evaluated using logistic regression analyses.

RESULTS AND LIMITATIONS

The cohort included 176 patients. IDC and ICC were observed in 77 (43.8%) and 80 (45.5%) RP specimens, respectively. The median time from RP to PSMA-PET/CT was 5.0 yr. The median serum prostate-specific antigen level at PSMA-PET/CT was 1.12 ng/ml. Overall, metastasis was observed in 77 patients, of whom 58 were had lymphatic-only metastasis. On a multivariable analysis, presence of IDC on RP was associated with increased odds of overall metastasis (odds ratio [OR]: 2.17; 95% confidence interval [CI]: 1.07-4.45; p = 0.033). Presence of ICC on RP was associated with significantly increased odds of lymphatic versus bone/visceral metastases (OR: 3.13; 95% CI: 1.09-21.7; p = 0.004).

CONCLUSIONS

Presence of cribriform morphology on RP specimens of patients with biochemical failure after RP is associated with increased odds of PSMA-PET/CT-detected metastases with a lymphatic predominant pattern of spread. These findings have implications for the design and evaluation of post-RP salvage therapies.

PATIENT SUMMARY

We found that microscopic cribriform appearance correlates with disease spread on imaging in prostate cancer patients with recurrence and has a predilection for spread to lymph nodes, as opposed to bone or visceral organs.

Nomogram for predicting the biochemical recurrence of prostate cancer after neoadjuvant androgen deprivation therapy

BACKGROUND

A predictive model for biochemical recurrence (BCR) of prostate cancer (PCa) after neoadjuvant androgen deprivation therapy (nADT) has not been established. This study was aimed at determining multiparameter variables that could be used to construct a nomogram to predict the post-nADT BCR of PCa.

METHODS

Overall, 43 radical prostatectomy specimens from PCa patients who had undergone nADT were collected. Multiparameter variables were analyzed by univariate and then multivariate logistic analyses to identify the independent prognostic factors for predicting BCR. The predictive model was established using Lasso regression analysis.

RESULTS

Univariate logistic analysis revealed six variables, pathology stage; margins; categorization as group A, B, or C; nucleolus grading; percentage of tumor involvement (PTI); and PTEN status were significantly associated with the BCR of PCa (all p < 0.05). Multivariate logistic regression analysis suggested that categorization as group C, severe nucleolus grading, PTI less than or equal to 5%, and PTEN loss were positively correlated with BCR (all p < 0.05). A nomogram comprising the four variables predicting BCR was constructed, and it exhibited good discrimination (AUC: 0.985; specificity: 86.2%; sensitivity: 100%). Calibration plots for the probability of freedom from BCR at 1 and 2 years showed a good match between the prediction by the nomogram.

CONCLUSIONS

We constructed and validated a nomogram to predict the risk of BCR in PCa patients after nADT. This nomogram is a complement to the existing risk stratification systems for PCa, which could have marked implications for clinical decision-making for PCa patients after nADT.

Predictive factors associated with differential pathologic response to neoadjuvant chemohormonal therapy in high-risk localized prostate cancer

PURPOSE

To explore the clinical parameters and molecular biomarkers that can predict differential pathologic response to neoadjuvant chemohormonal therapy (NCHT) in prostate cancer (CaP).

METHODS

A total of 128 patients with primary high-risk localized CaP who had received NCHT followed by radical prostatectomy (RP) were included. Androgen receptor (AR), AR splice variant-7 (AR-V7) and Ki-67 staining were evaluated in prostate biopsy specimens by immunohistochemistry. The pathologic response to NCHT in whole mount RP specimens was measured based on the reduction degree of tumor volume and cellularity compared to the paired pretreatment needle biopsy, and divided into 5 tier grades (Grades 0-4). Patients with Grades 2 to 4 (the reduction degree more than 30%) were defined as having a favorable response. Logistic regression was performed to explore the predictive factors associated with a favorable pathologic response. The predictive accuracy was evaluated by receiver operating characteristic (ROC) curve and area under the ROC curve (AUC).

RESULTS

Ninety-seven patients (75.78%) had a favorable response to NCHT. Logistic regression showed that the preoperative PSA level, low AR expression and high Ki-67 expression in biopsy specimens were associated with a favorable pathologic response (P < 0.05). Furthermore, the AUC of the preoperative PSA level, AR and Ki-67 were 0.625, 0.624 and 0.723, respectively. Subgroup analysis revealed that the rate of favorable pathologic response to NCHT was 88.5% in patients with AR^lowKi-67^high, which was higher than patients with AR^lowKi-67^low, AR^highKi-67^low, and AR^highKi-67^high (88.5% vs. 73.9%, 72.9%, and 70.9%, all P < 0.05).

CONCLUSIONS

A lower preoperative PSA level was an independent predictive factor for a favorable pathologic response. Moreover, the expression status of AR and Ki-67 in biopsy specimens were associated with differential pathologic response to NCHT, and AR low/Ki-67 high was also associated with favorable response but warrants further evaluation in this patient subgroup and future trial clinical trial design.

Emerging RNA-Based Therapeutic and Diagnostic Options: Recent Advances and Future Challenges in Genitourinary Cancers

Renal cell carcinoma, bladder cancer, and prostate cancer are the most widespread genitourinary tumors. Their treatment and diagnosis have significantly evolved over recent years, due to an increasing understanding of oncogenic factors and the molecular mechanisms involved. Using sophisticated genome sequencing technologies, the non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, have all been implicated in the occurrence and progression of genitourinary cancers. Interestingly, DNA, protein, and RNA interactions with lncRNAs and other biological macromolecules drive some of these cancer phenotypes. Studies on the molecular mechanisms of lncRNAs have identified new functional markers that could be potentially useful as biomarkers for effective diagnosis and/or as targets for therapeutic intervention. This review focuses on the mechanisms underlying abnormal lncRNA expression in genitourinary tumors and discusses their role in diagnostics, prognosis, and treatment.

Identification of miR-1-3p, miR-143-3p and miR-145-5p association with bone metastasis of Gleason 3+4 prostate cancer and involvement of LASP1 regulation

Gleason Score (GS) 3 + 4 prostate cancer (PCa) is heterogeneous in clinical course and molecular features. Risk stratification of indolent and aggressive PCa with GS 3 + 4 is critical, especially those with bone metastasis (BM) potential. Microarray-based microRNA(miRNA) profiling with eight PCa cases with or without BM was used to screen the candidate miRNAs associated with BM. Transwell and MTS assays were used to characterize the function of miRNAs and target gene LASP1. RT-qPCR and immunohistochemistry assays were utilized to illustrate the clinical significance of miRNAs and target gene in a cohort of 309 Chinese PCa cases. In the current study, we identified that miR-1-3p, miR-143-3p and miR-145-5p are associated with BM of GS 3 + 4 PCa. Through functional experiments, we show that miR-1-3p/143-3p/145-5p promotes proliferation and migration of PCa in vitro. LASP1 was predicted as the common target of these three miRNAs which was further confirmed by a luciferase assay. Overexpression of LASP1 was correlated with higher GS, higher pathological stage, and the presence of metastasis by immunohistochemistry. siRNA knockdown of LASP1 significantly suppressed proliferation and migration, whereas overexpression of LASP1 promoted it. Bioinformatics analysis revealed the involvement of Wnt signaling pathway in LASP1 mediated function. LASP1 may activate Wnt signaling by interacting with β-catenin. In all, we suggest that miR-1-3p/143-3p/145-5p are associated with BM of Gleason 3 + 4 PCa. LASP1 is the common target of these miRNAs and may active Wnt signaling by interacting with β-catenin.

A trio of tumor suppressor miRNA downregulates CREB5 dependent transcription to modulate neoadjuvant hormonal therapy sensitivity

Neoadjuvant hormonal therapy (NHT) prior to radical prostatectomy (RP) is an approach that can potentially maximize survival outcomes in prostate cancer (PCa) patients with high-risk disease. Unfortunately, subsets of patients do not respond well to such hormonal therapy. We previously identified several pathological parameters in predicting differences in response to NHT of PCa. However, little is known about the potential role and mechanism of miRNAs mediated NHT resistance (NHT-R) in PCa. Here we demonstrate that miR-l42-3p, miR-150-5p and miR-342-3p are the top downregulated miRNAs in PCa tissues with NHT-R. Functional analysis reveals that the three miRNAs inhibit cell proliferation in vitro. Transfection of miRNAs mimics strengthens the inhibitory effects of bicalutamide and enzalutamide to PCa cells. Luciferase reporter assay reveals that CREB5 is the common target of these three miRNAs. Clinically, high expression level of CREB5 correlates with high Gleason score, advanced tumor stage and NHT-R in PCa tissues. CREB5 expression promotes antiandrogen therapy resistance in LNCaP cells and IL6 signaling pathway may be involved in this process. In all, our findings highlight an important role of miR-142-3p, miR-150-5p, and miR-342-3p in contributing NHT-R by targeting CREB5 in PCa.

Prostate Cancer in Male-to-Female Transgender Individuals: Histopathologic Findings and Association With Gender-affirming Hormonal Therapy

Male-to-female (MtF) transgender individuals are at risk for prostate cancer, although guidelines for screening and management in this population are not well established. We describe a series of 9 MtF transgender patients who underwent prostate tissue sampling and highlight histopathologic features and challenges related to pathologic interpretation of prostate tissue in this patient population. Seven of 9 total patients were diagnosed with prostate cancer and all had elevated prostate-specific antigen at the time of diagnosis. Three of the 7 patients diagnosed with prostate cancer had received different types of hormone therapy for gender affirmation before the diagnosis of prostate cancer, and in all 3 of these patients, there was histologic evidence of hormone therapy effect in both benign prostate tissue and/or the adenocarcinoma. The 2 patients with benign prostate tissue underwent transurethral resection for lower urinary tract symptoms and were previously on hormone therapy for gender affirmation. Both of these specimens showed diffuse glandular atrophy and basal cell hyperplasia, indicative of hormone therapy effect on benign prostatic tissue. In the patients diagnosed with prostate cancer, a spectrum of grades was observed, ranging from Grade Group 1 to Grade Group 5. Four patients underwent radical prostatectomy, with 2 cases showing extraprostatic extension and Grade Group 5 prostatic adenocarcinoma, and 2 showing Grade Group 2 prostatic adenocarcinoma. Three of the 4 patients who underwent radical prostatectomy had received gender-affirming hormone therapy before surgery, and all 3 of these specimens showed hormone therapy effect in non-neoplastic prostate tissue and focal hormone therapy effect in prostatic adenocarcinoma. The presence of areas of viable carcinoma without hormone therapy effect enabled the assignment of a Gleason score and Grade Group in these 3 cases. Hormone therapy administered for gender identity affirmation induces histopathologic changes to both benign prostate tissue (nonkeratinizing squamous metaplasia, diffuse atrophy, basal cell hyperplasia, and stromal dominance with decreased numbers of glands) and prostatic adenocarcinoma (nuclear pyknosis, atrophy, cytoplasmic vacuolization, and architectural patterns that would qualify for Gleason 4 and 5 in the absence of hormone therapy effect) that have been traditionally seen in cis-male prostate cancer patients receiving hormone therapy. In the absence of hormone therapy, the morphology of prostatic adenocarcinoma in transgender patients shows classic morphologic features similar to those seen in cis-male patients not on hormone therapy. Prostate cancer with hormone therapy effect may not only be histologically quite subtle and may be overlooked if not suspected, but also should not be assigned a Gleason score because the Gleason score would substantially overstate its biologic potential. Therefore, similar to cis-male patients who have received androgen deprivation therapy for prostate cancer, transgender patients on hormone therapy for gender affirmation may be at risk for both underrecognition and over-grading of prostate cancer, particularly if the pathologist is not aware of the clinical history.

Neoadjuvant Hormonal Therapy for Prostate Cancer: Morphologic Features and Predictive Parameters of Therapy Response

The primary goals of neoadjuvant hormonal therapy (NHT) in prostate cancer (PCa) are to reduce the size of the tumor, lower positive surgical margin rate, attempt to reach pathologic remission, and improve survival. Although NHT has not been recommended by the National Comprehensive Cancer Network as a primary treatment option for patients with localized PCa, NHT is increasingly used in clinical trials for locally advanced PCa. More importantly, with the development of novel androgen signaling inhibitors, such as abiraterone and enzalutamide, there has been renewed interests in revisiting the role of such treatment in the neoadjuvant setting. Following NHT, the PCa tissues shows characteristic morphologic alterations. Of note, the collapse of malignant glands most likely leads to an artificial increase of Gleason score in the residual disease. Communicating these changes to the clinician in a way that can help assess the tumor's response poses a challenge for pathologists. In addition, little is known of morphologic features and predictive makers both in pretreated and posttreated specimens that can be of value in predicting tumor response to NHT. In the current review, we summarize the morphologic changes associated with neoadjuvant-treated PCa, focusing on the predictive value of pathologic parameters to therapy response. We also describe the evaluation system in the stratification of pathologic response to NHT in PCa management.

Modeling Androgen Deprivation Therapy-Induced Prostate Cancer Dormancy and Its Clinical Implications

Treatment-induced tumor dormancy is a state in cancer progression where residual disease is present but remains asymptomatic. Dormant cancer cells are treatment-resistant and responsible for cancer recurrence and metastasis. Prostate cancer treated with androgen-deprivation therapy (ADT) often enters a dormant state. ADT-induced prostate cancer dormancy remains poorly understood due to the challenge in acquiring clinical dormant prostate cancer cells and the lack of representative models. In this study, we aimed to develop clinically relevant models for studying ADT-induced prostate cancer dormancy. Dormant prostate cancer models were established by castrating mice bearing patient-derived xenografts (PDX) of hormonal naïve or sensitive prostate cancer. Dormancy status and tumor relapse were monitored and evaluated. Paired pre- and postcastration (dormant) PDX tissues were subjected to morphologic and transcriptome profiling analyses. As a result, we established eleven ADT-induced dormant prostate cancer models that closely mimicked the clinical courses of ADT-treated prostate cancer. We identified two ADT-induced dormancy subtypes that differed in morphology, gene expression, and relapse rates. We discovered transcriptomic differences in precastration PDXs that predisposed the dormancy response to ADT. We further developed a dormancy subtype-based, predisposed gene signature that was significantly associated with ADT response in hormonal naïve prostate cancer and clinical outcome in castration-resistant prostate cancer treated with ADT or androgen-receptor pathway inhibitors.

IMPLICATIONS

We have established highly clinically relevant PDXs of ADT-induced dormant prostate cancer and identified two dormancy subtypes, leading to the development of a novel predicative gene signature that allows robust risk stratification of patients with prostate cancer to ADT or androgen-receptor pathway inhibitors.

The Crosstalk of Long Non-Coding RNA and MicroRNA in Castration-Resistant and Neuroendocrine Prostate Cancer: Their Interaction and Clinical Importance

Prostate cancer is featured by its heterogeneous nature, which indicates a different prognosis. Castration-resistant prostate cancer (CRPC) is a hallmark of the treatment-refractory stage, and the median survival of patients is only within two years. Neuroendocrine prostate cancer (NEPC) is an aggressive variant that arises from de novo presentation of small cell carcinoma or treatment-related transformation with a median survival of 1–2 years from the time of diagnosis. The epigenetic regulators, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), have been proven involved in multiple pathologic mechanisms of CRPC and NEPC. LncRNAs can act as competing endogenous RNAs to sponge miRNAs that would inhibit the expression of their targets. After that, miRNAs interact with the 3’ untranslated region (UTR) of target mRNAs to repress the step of translation. These interactions may modulate gene expression and influence cancer development and progression. Otherwise, epigenetic regulators and genetic mutation also promote neuroendocrine differentiation and cancer stem-like cell formation. This step may induce neuroendocrine prostate cancer development. This review aims to provide an integrated, synthesized overview under current evidence to elucidate the crosstalk of lncRNAs with miRNAs and their influence on castration resistance or neuroendocrine differentiation of prostate cancer. Notably, we also discuss the mechanisms of lncRNA–miRNA interaction in androgen receptor-independent prostate cancer, such as growth factors, oncogenic signaling pathways, cell cycle dysregulation, and cytokines or other transmembrane proteins. Conclusively, we underscore the potential of these communications as potential therapeutic targets in the future.

Biomarkers of Response to Neoadjuvant Androgen Deprivation in Localised Prostate Cancer

Simple Summary

Prostate cancer is the second leading cause of cancer deaths in men. Attempts to improve patient outcomes include trials of neoadjuvant androgen deprivation therapy for patients with high-risk disease. Neoadjuvant treatment refers to androgen deprivation therapy that is administered prior to surgery (or radiation therapy). Patients typically respond well to this treatment regimen, showing a decrease in tumour size, but a significant proportion of patients eventually relapse and progress to metastatic disease. The mechanisms driving this resistance to neoadjuvant treatment are currently unknown. This review explores theories of resistance broadly, and their possible applications in the prostate cancer setting. Additionally, this review draws comparisons between breakthrough resistance and neoadjuvant resistance, and lastly investigates the current biomarkers for treatment sensitivity.

Abstract

Prostate cancer (PCa) is a hormone driven cancer, characterised by defects in androgen receptor signalling which drive the disease process. As such, androgen targeted therapies have been the mainstay for PCa treatment for over 70 years. High-risk PCa presents unique therapeutic challenges, namely in minimising the primary tumour, and eliminating any undetected micro metastases. Trials of neoadjuvant androgen deprivation therapy aim to address these challenges. Patients typically respond well to neoadjuvant treatment, showing regression of the primary tumour and negative surgical margins at the time of resection, however the majority of patients relapse and progress to metastatic disease. The mechanisms affording this resistance are largely unknown. This commentary attempts to explore theories of resistance more broadly, namely, clonal evolution, cancer stem cells, cell persistence, and drug tolerance. Moreover, it aims to explore the application of these theories in the PCa setting. This commentary also highlights the distinction between castration resistant PCa, and neoadjuvant resistant disease, and identifies the markers and characteristics of neoadjuvant resistant disease presented by current literature.

Pathological significance and prognostic role of LATS2 in prostate cancer

BACKGROUND

Large tumor suppressor 2 (LATS2) is an important regulator of the Hippo pathway and it plays crucial roles in cell survival and behaviors. Herein, we evaluated the pathological roles of LATS2 in prostate cancer (PC), for which very little information is available.

METHODS

Cell proliferation, migration, and invasion in response to the siRNA-mediated knockdown (KD) LATS2 expression were evaluated in two PC cell lines (LNCaP and PC3). The expression of LATS2 in specimens from 204 PC patients was investigated immunohistochemically, and the relationships between its expression and clinicopathological features, proliferation index (PI; measured using an anti-KI-67 antibody), and biochemical recurrence (BCR) were investigated.

RESULTS

KD of LATS2 increased the growth, migration, and invasion in LNCaP cells and only increased migration in PC3 cells. The expression of LATS2 was negatively associated with the grade group, T, N, M stage, and PI. In addition, the expression of LATS2 was a useful predictor of the histological effects of neoadjuvant hormonal therapy and BCR-free survival periods. A multivariate analysis model including clinicopathological features showed that negative expression of LATS2 had a significantly higher risk of BCR (odds ratio = 2.95, P < 0.001).

CONCLUSIONS

LATS2 acts as a tumor suppressor in PC. LATS2 expression is a useful predictor for BCR. LATS2-related activities are possibly dependent on the androgen-dependency of PC cells. Therefore, we suggest that LATS2 could be a potential therapeutic target and a useful predictor for outcome in patients with PC.

Knowing what's growing: Why ductal and intraductal prostate cancer matter

Prostate cancer is a common malignancy, but only some tumors are lethal. Accurately identifying these tumors will improve clinical practice and instruct research. Aggressive cancers often have distinctive pathologies, including intraductal carcinoma of the prostate (IDC-P) and ductal adenocarcinoma. Here, we review the importance of these pathologies because they are often overlooked, especially in genomics and preclinical testing. Pathology, genomics, and patient-derived models show that IDC-P and ductal adenocarcinoma accompany multiple markers of poor prognosis. Consequently, "knowing what is growing" will help translate preclinical research to pinpoint and treat high-risk prostate cancer in the clinic.

Cribriform Prostate Cancer: Clinical Pathologic and Molecular Considerations

Intraductal cribriform (IDC) and invasive cribriform morphologies are associated with worse prostate cancer outcomes. Limited retrospective studies have associated IDC and cribriform morphology with germline mutations in DNA repair genes, particularly BRCA2. These findings, which prompted the National Comprehensive Cancer Network (NCCN) Guidelines for Prostate Cancer and Genetic/Familial High- Risk Assessment to consider germline testing for individuals with IDC/cribriform histology, have been questioned in a recent prospective study. A deepened understanding of the molecular mechanisms driving disease aggressiveness in cribriform morphology is critical to provide more clarity in clinical decision making. This review summarizes the current understanding of IDC and cribriform prostate cancer, with an emphasis on clinical outcomes and molecular alterations.

Optimizing the diagnosis and management of ductal prostate cancer

Ductal adenocarcinoma (DAC) is the most common variant histological subtype of prostate carcinoma and has an aggressive clinical course. DAC is usually characterized and treated as high-risk prostatic acinar adenocarcinoma (PAC). However, DAC has a different biology to that of acinar disease, which often poses a challenge for both diagnosis and management. DAC can be difficult to identify using conventional diagnostic modalities such as serum PSA levels and multiparametric MRI, and the optimal management for localized DAC is unknown owing to the rarity of the disease. Following definitive therapy for localized disease with radical prostatectomy or radiotherapy, the majority of DACs recur with visceral metastases at low PSA levels. Various systemic therapies that have been shown to be effective in high-risk PAC have limited use in treating DAC. Although current understanding of the biology of DAC is limited, genomic analyses have provided insights into the pathology behind its aggressive behaviour and potential future therapeutic targets.

Ductal Prostate Cancers Demonstrate Poor Outcomes with Conventional Therapies

BACKGROUND

Ductal prostate adenocarcinoma (DAC) is a rare, aggressive, histologic variant of prostate cancer that is treated with conventional therapies, similar to high-risk prostate adenocarcinoma (PAC).

OBJECTIVE

To assess the outcomes of men undergoing definitive therapy for DAC or high-risk PAC and to explore the effects of androgen deprivation therapy (ADT) in improving the outcomes of DAC.

DESIGN, SETTING, AND PARTICIPANTS

A single-center retrospective review of all patients with cT1-4/N0-1 DAC from 2005 to 2018 was performed. Those undergoing radical prostatectomy (RP) or radiotherapy (RTx) for DAC were compared with cohorts of high-risk PAC patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Metastasis-free survival (MFS) and overall survival (OS) rates were analyzed using Kaplan-Meier and Cox regression models.

RESULTS AND LIMITATIONS

A total of 228 men with DAC were identified; 163 underwent RP, 34 underwent RTx, and 31 had neoadjuvant therapy prior to RP. In this study, 163 DAC patients and 155 PAC patients undergoing RP were compared. Similarly, 34 DAC patients and 74 PAC patients undergoing RTx were compared. DAC patients undergoing RP or RTx had worse 5-yr MFS (75% vs 95% and 62% vs 93%, respectively, p < 0.001) and 5-yr OS (88% vs 97% and 82% vs 100%, respectively, p < 0.05) compared with PAC patients. In the 76 men who received adjuvant/salvage ADT after RP, DAC also had worse MFS and OS than PAC (p < 0.01). A genomic analysis revealed that 10/11 (91%) DACs treated with ADT had intrinsic upregulation of androgen-resistant pathways. Further, none of the DAC patients (0/15) who received only neoadjuvant ADT prior to RP had any pathologic downgrading. The retrospective nature was a limitation.

CONCLUSIONS

Men undergoing RP or RTx for DAC had worse outcomes than PAC patients, regardless of the treatment modality. Upregulation of several intrinsic resistance pathways in DAC rendered ADT less effective. Further evaluation of the underlying biology of DAC with clinical trials is needed.

PATIENT SUMMARY

This study demonstrated worse outcomes among patients with ductal adenocarcinoma of the prostate than among high-grade prostate adenocarcinoma patients, regardless of the treatment modality.

Development and prevalence of castration-resistant prostate cancer subtypes

BACKGROUND

Castration-resistant prostate cancer (CRPC) occurs when prostate cancer (CaP) progresses under therapy-induced castrate conditions. Several mechanisms have been proposed to explain this acquired resistance, many of which are driven by androgen receptor (AR). Recent findings, however, sub-classified CRPC by downregulation/absence of AR in certain subtypes that consequently do not respond to anti-androgen therapies. To highlight the significance of CRPC sub-classification, we reviewed the development and treatment of CRPC, AR downregulation in CRPC, and summarized recent reports on the prevalence of CRPC subtypes.

METHODS

Using a medline-based literature search, we reviewed mechanisms of CRPC development, current treatment schemes, and assessed the prevalence of AR low/negative subtypes of CRPC. Additionally, we performed immunohistochemical staining on human CRPC specimens to quantify AR expression across CRPC subtypes.

RESULTS

In the majority of cases, CRPC continues to rely on AR signaling, which can be augmented in castrate-conditions through a variety of mechanisms. However, recently low/negative AR expression patterns were identified in a significant proportion of patient samples from a multitude of independent studies. In these AR low/negative cases, we postulated that AR protein may be downregulated by (1) promoter methylation, (2) transcriptional regulation, (3) post-transcriptional regulation by microRNA or RNA-binding-proteins, or (4) post-translational ubiquitination-mediated degradation.

CONCLUSIONS

Here, we discussed mechanisms of CRPC development and summarized the overall prevalence of CRPC subtypes; interestingly, AR low/negative CRPC represented a considerable proportion of diagnoses. Because these subtypes cannot be effectively treated with AR-targeted therapeutics, a better understanding of AR low/negative subtypes could lead to better treatment strategies and increased survival.