Association of extended core sampling with delayed intervention and pathologic outcomes for active surveillance patients A population-based analysis.

INTRODUCTION: Combined systematic plus targeted biopsy sampling improves detection of clinically significant prostate cancer (PCa). Our objective was to evaluate whether extended core sampling at initial biopsy in active surveillance (AS) patients is associated with subsequent AS discontinuation and pathologic outcomes. METHODS: National Comprehensive Cancer Network (NCCN) low- and favorable-intermediate-risk (FIR) AS patients diagnosed between 2010 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) Prostate with Watchful Waiting database. Prostate biopsy sampling was operationalized as: standard (10-12 cores), extended (13-20 cores), or super-extended (21+ cores). Sensitivity analyses using differing cutoffs was performed. Outcomes included delayed definitive intervention (radical prostatectomy [RP]/radiotherapy) and pathologic upgrading and/or downgrading in delayed RP patients. Multivariable logistic regression modelling adjusted for sociodemographic/oncologic variables was performed. RESULTS: This cohort included 42 459 patients (low-risk: 28 411; FIR:14 048); 25-29% and 3-5% of patients underwent extended and super-extended core sampling, respectively, at diagnosis. Extended core sampling was associated with decreased odds of definitive intervention in low (odds ratio [OR] 0.89, p=0.003) and grade group 2 (GG2) FIR (OR 0.83, p=0.002) patients. Super-extended sampling was associated with decreased odds of definitive intervention in prostate-specific antigen (PSA) 10-20 FIR patients (OR 0.65, p=0.02). Super-extended sampling was associated with decreased odds of upgrading to ≥GG2 disease in low-risk (OR 0.45, p=0.032) and to ≥GG3 disease in GG2 FIR patients (OR 0.67, p=0.044). CONCLUSIONS: This population-based analysis demonstrates that extended/super-extended sampling at diagnosis is associated with significantly decreased odds of AS discontinuation and pathologic upgrading in low/FIR AS patients. This highlights the significance of extended tissue sampling at initial biopsy to appropriately risk-stratify AS patients and minimize AS discontinuation rates.

Limitations of Prostate Biopsy in Detection of Cribriform and Intraductal Prostate Cancer.

BACKGROUND: The presence of cribriform morphology and intraductal carcinoma (IDC) in prostate biopsies and radical prostatectomy specimens is an adverse prognostic feature that can be used to guide treatment decisions. OBJECTIVE: To assess how accurately biopsies can detect cribriform morphology and IDC cancer by examining matched biopsy and prostatectomy samples. DESIGN, SETTING, AND PARTICIPANTS: Patients who underwent radical prostatectomy at The Princess Margaret Cancer Centre between January 2015 and December 2022 and had cribriform morphology and/or IDC in the surgical specimen were included in the study. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used detection sensitivity to evaluate the level of agreement between biopsy and prostatectomy samples regarding the presence of cribriform morphology and IDC. RESULTS AND LIMITATIONS: Of the 287 men who underwent radical prostatectomy, 241 (84%) had cribriform morphology and 161 (56%) had IDC on final pathology. The sensitivity of prostate biopsy, using radical prostatectomy as the reference, was 42.4% (95% confidence interval [CI] 36-49%) for detection of cribriform morphology and 44.1% (95% CI 36-52%) for detection of IDC. The sensitivity of prostate biopsy for detection of either IDC or cribriform morphology was 52.5% (95% CI 47-58%). Among patients who underwent multiparametric magnetic resonance imaging-guided biopsies, the sensitivity was 54% (95% CI 39-68%) for detection of cribriform morphology and 37% (95% CI 19-58%) for detection of IDC. CONCLUSIONS: Biopsy has low sensitivity for detecting cribriform morphology and IDC. These limitations should be incorporated into clinical decision-making. Biomarkers for better detection of these histological patterns are needed. PATIENT SUMMARY: Prostate biopsy is not an accurate method for detecting two specific types of prostate cancer cells, called cribriform pattern and intraductal prostate cancer, which are associated with unfavorable prognosis.

The Antiarrhythmic Drug, Dronedarone, Demonstrates Cytotoxic Effects in Breast Cancer Independent of Thyroid Hormone Receptor Alpha 1 (THRα1) Antagonism.

Previous research has suggested that thyroid hormone receptor alpha 1 (THRα1), a hormone responsive splice variant, may play a role in breast cancer progression. Whether THRα1 can be exploited for anti-cancer therapy is unknown. The antiproliferative and antitumor effects of dronedarone, an FDA-approved anti-arrhythmic drug which has been shown to antagonize THRα1, was evaluated in breast cancer cell lines in vitro and in vivo. The THRα1 splice variant and the entire receptor, THRα, were also independently targeted using siRNA to determine the effect of target knockdown in vitro. In our study, dronedarone demonstrates cytotoxic effects in vitro and in vivo in breast cancer cell lines at doses and concentrations that may be clinically relevant. However, knockdown of either THRα1 or THRα did not cause substantial anti-proliferative or cytotoxic effects in vitro, nor did it alter the sensitivity to dronedarone. Thus, we conclude that dronedarone's cytotoxic effect in breast cancer cell lines are independent of THRα or THRα1 antagonism. Further, the depletion of THRα or THRα1 does not affect cell viability or proliferation. Characterizing the mechanism of dronedarone's anti-tumor action may facilitate drug repurposing or the development of new anti-cancer agents.

Differential roles of RET isoforms in medullary and papillary thyroid carcinomas.

The RET receptor tyrosine kinase mediates cell proliferation, survival and migration in embryogenesis and is implicated in the transformation and tumour progression in multiple cancers. RET is frequently mutated and constitutively activated in familial and sporadic thyroid carcinomas. As a result of alternative splicing, RET is expressed as two protein isoforms, RET9 and RET51, which differ in their unique C-terminal amino acids. These isoforms have distinct intracellular trafficking and associated signalling complexes, but functional differences are not well defined. We used shRNA-mediated knockdown (KD) of individual RET isoforms or of total RET to evaluate their functional contributions in thyroid carcinoma cells. We showed that RET is required for cell survival in medullary (MTC) but not papillary thyroid carcinoma (PTC) cells. In PTC cells, RET depletion reduced cell migration and induced a flattened epithelial-like morphology. RET KD decreased the expression of mesenchymal markers and matrix metalloproteinases and reduced anoikis resistance and invasive potential. Further, we showed that RET51 depletion had significantly greater effects on each of these processes than RET9 depletion in both MTC and PTC cells. Finally, we showed that expression of RET, particularly RET51, was correlated with malignancy in a panel of human thyroid tumour tissues. Together, our data show that RET expression promotes a more mesenchymal phenotype with reduced cell-cell adhesion and increased invasiveness in PTC cell models, but is more important for tumour cell survival, proliferation and anoikis resistance in MTC models. Our data suggest that the RET51 isoform plays a more prominent role in mediating these processes compared to RET9.

The effects of lymph node status on predicting outcome in ER+ /HER2- tamoxifen treated breast cancer patients using gene signatures.

BACKGROUND: Lymph node (LN) status is the most important prognostic variable used to guide ER positive (+) breast cancer treatment. While a positive nodal status is traditionally associated with a poor prognosis, a subset of these patients respond well to treatment and achieve long-term survival. Several gene signatures have been established as a means of predicting outcome of breast cancer patients, but the development and indication for use of these assays varies. Here we compare the capacity of two approved gene signatures and a third novel signature to predict outcome in distinct LN negative (-) and LN+ populations. We also examine biological differences between tumours associated with LN- and LN+ disease. METHODS: Gene expression data from publically available data sets was used to compare the ability of Oncotype DX and Prosigna to predict Distant Metastasis Free Survival (DMFS) using an in silico platform. A novel gene signature (Ellen) was developed by including patients with both LN- and LN+ disease and using Prediction Analysis of Microarrays (PAM) software. Gene Set Enrichment Analysis (GSEA) was used to determine biological pathways associated with patient outcome in both LN- and LN+ tumors. RESULTS: The Oncotype DX gene signature, which only used LN- patients during development, significantly predicted outcome in LN- patients, but not LN+ patients. The Prosigna gene signature, which included both LN- and LN+ patients during development, predicted outcome in both LN- and LN+ patient groups. Ellen was also able to predict outcome in both LN- and LN+ patient groups. GSEA suggested that epigenetic modification may be related to poor outcome in LN- disease, whereas immune response may be related to good outcome in LN+ disease. CONCLUSIONS: We demonstrate the importance of incorporating lymph node status during the development of prognostic gene signatures. Ellen may be a useful tool to predict outcome of patients regardless of lymph node status, or for those with unknown lymph node status. Finally we present candidate biological processes, unique to LN- and LN+ disease, that may indicate risk of relapse.

Identification and evaluation of network modules for the prognosis of basal-like breast cancer.

PURPOSE: Basal-like breast cancer (BLBC) is a molecular subtype of breast cancer associated with poor clinical outcome, although some patients with BLBC experience long-term survival. Apart from nodal status, current clinical/histopathological variables show little capacity to identify BLBC patients at either high- or low-risk of disease recurrence. Accordingly, we sought to develop a network based genomic predictor for predicting the outcome of patients with BLBC. EXPERIMENTAL DESIGN: We performed network analysis on global gene expression profiling data of BLBCs, and identified BLBC network modules associated with AP-1 transcription, G-protein coupled receptors, and T-, B-, and NK-cells that are significant predictors of BLBC patient survival. RESULTS: In gene expression and tissue microarray (TMA) validation cohorts of 210 and 102 BLBC patients, respectively, the identified network modules were robustly associated with patient outcome. In the gene expression validation cohort, the Kaplan-Meier estimate for 10-year survival in the low-risk group was 90%, whereas in the high-risk group it was a 56%. In the TMA cohort, the Kaplan-Meier estimate for 10-year survival in the low-risk group was 98%, whereas in the high-risk group it was 71%. CONCLUSIONS: The capacity to distinguish between patients with BLBC at high- or low-risk of recurrence at the time of diagnosis could permit timely intervention with more aggressive therapeutic regimens in those patients predicted to be high-risk, and to avoid such therapy in low-risk patients.

Multiple functional effects of RET kinase domain sequence variants in Hirschsprung disease.

The REarranged during Transfection (RET) gene encodes a receptor tyrosine kinase required for maturation of the enteric nervous system. RET sequence variants occur in the congenital abnormality Hirschsprung disease (HSCR), characterized by absence of ganglia in the intestinal tract. Although HSCR-RET variants are predicted to inactivate RET, the molecular mechanisms of these events are not well characterized. Using structure-based models of RET, we predicted the molecular consequences of 23 HSCR-associated missense variants and how they lead to receptor dysfunction. We validated our predictions in biochemical and cell-based assays to explore mutational effects on RET protein functions. We found a minority of HSCR-RET variants abrogated RET kinase function, while the remaining mutants were phosphorylated and transduced intracellular signals. HSCR-RET sequence variants also impacted on maturation, stability, and degradation of RET proteins. We showed that each variant conferred a unique combination of effects that together impaired RET protein activity. However, all tested variants impaired RET-mediated cellular functions, including cell transformation and migration. Our data indicate that the molecular mechanisms of impaired RET function in HSCR are highly variable. Although a subset of variants cause loss of RET kinase activity and downstream signaling, enzymatic inactivation is not the sole mechanism at play in HSCR.

RET-mediated cell adhesion and migration require multiple integrin subunits.

CONTEXT: The RET receptor tyrosine kinase is an important mediator of several human diseases, most notably of neuroendocrine cancers. These diseases are characterized by aberrant cell migration, a process tightly regulated by integrins. OBJECTIVE: Our goals were to investigate the role of integrins in RET-mediated migration in two neoplastic cell models: the neural-derived cell line SH-SY5Y, and the papillary thyroid carcinoma cell line TPC-1. We also evaluated whether multiple integrin subunits have a role in RET-mediated cell migration. DESIGN: We evaluated the expression and activation of integrins in response to RET activation using standard cell adhesion and migration (wound-healing) assays. We examined focal adhesion formation, using integrin-paxillin coimmunoprecipitations and immunofluorescence, as an indicator of integrin activity. RESULTS: Our data indicate that ß1 integrin (ITGB1) is expressed in both SH-SY5Y and TPC-1 cell lines and that these cells adhere strongly to matrices preferentially associated with ITGB1. We showed that RET can activate ITGB1, and that RET-induced cell adhesion and migration require ITGB1. Furthermore, we showed that ß3 integrin (ITGB3) also plays a role in RET-mediated cell adhesion and migration in vitro and ITGB3 expression correlates with RET-mediated invasion in a mouse tumor xenograft model, suggesting that RET mediates the activity of multiple integrin subunits. CONCLUSIONS: Our data are the first to show that multiple integrin subunits contribute to cell adhesion and migration downstream of RET, suggesting that coordinated signaling through these pathways is important for cell interactions with the microenvironment during tumor invasion and progression.