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Identification of Differential Tumor Subtypes of T1 Bladder Cancer

ABSTRACT: Stage T1 bladder cancers have the highest progression and recurrence rates of all non-muscle invasive bladder tumors. T1 tumors are heterogeneous; while most T1 patients are treated with BCG, many will progress and die from bladder cancer, and particularly aggressive tumors could be treated by early cystectomy. To better understand the molecular heterogeneity of T1 cancers, we performed transcriptome profiling and unsupervised clustering, identifying five consensus subtypes of T1 tumors treated with reTUR, induction and maintenance BCG. The T1-LumGU subtype was associated with CIS (6/13, 46% of all CIS), had high E2F1 and EZH2 expression, and enriched E2F target and G2M checkpoint Hallmarks. T1-Inflam was inflamed and infiltrated with immune cells. While most T1 tumors were classified as luminal papillary, the T1-TLum subtype had the highest median Luminal Papillary score and FGFR3 expression, no recurrence events, and the fewest copy number gains. T1-Myc and T1-Early subtypes had the most recurrences (14/30 within 24 months), highest median MYC expression, and, when combined, had significantly worse recurrence-free survival than the other three subtypes. T1-Early had 5 (38%) recurrences within the first 6 months of BCG, and repressed IFN-alpha and IFN-gamma Hallmarks and inflammation. We developed a single-patient T1 classifier and validated our subtype biology in a second cohort of T1 tumors. Future research will be necessary to validate the proposed T1 subtypes and to determine if therapies can be individualized for each subtype.

ORGANISM(S): Homo sapiens

PROVIDER: GSE154261 | GEO | 2020/07/13

REPOSITORIES: GEO

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Project description:Full title: Predictive Gene Signatures as Strong Prognostic Indicators of the Effectiveness of Bacillus Calmetteâ??GuÃ©rin (BCG) Immunotherapy in Primary pT1 Bladder Cancers Intravesical BCG immunotherapy is effective in prevention of recurrence and progression in many cases of non-muscle invasive bladder cancer, but many patients fail to respond. This study identified predictive gene signatures in primary pT1 bladder cancer with BCG immunotherapy. Fourty-Eight patients with primary pT1 bladder cancer treated with BCG immunotherapy were used. Microarray gene expression analysis of the 48 primary bladder cancers was carried out. Predictive gene signatures were individually selected based on the recurrence and progression status. Among 43,148 unique genes, 424 and 287 candidate predictive genes that could predict recurrence and progression, respectively, were selected. Time to recurrence or progression was shorter for patients with poor-predictive gene signatures than good-predictive gene signatures (log-rank test, p <0.001, respectively). Validation of predictive gene signatures with RT-PCR was nearly identical to those of microarray (log-rank test, p <0.05, respectively). In multivariate regression analysis, predictive gene signatures were the only independent predictors of recurrence (HR 3.38, p = 0.048) or progression (HR 10.49, p = 0.048) in validation cohorts. Predictive gene signatures have strong diagnostic value for determining the response to intravesical BCG immunotherapy in primary pT1 bladder cancer. Keywords: Gene expression, Bladder cancer, BCG Total RNA, extracted from the fresh frozen tissues of 48 pT1 bladder cancers, was isolated by TRIzol reagent (Life Technologies, NY, USA), according to the manufacturer's protocol. The quality and integrity of the RNA were confirmed by agarose gel electrophoresis and ethidium bromide staining, followed by visual examination under ultraviolet light. Five-hundred nanograms of total RNA were used for labeling hybridization according to the manufacturerâ??s protocol (Illumina HumanWG-6 BeadChip, version 2, Illumina, Inc., San Diego, CA, USA). Arrays were scanned with an Illumina Bead Array Reader confocal scanner (BeadStation 500GXDW; Illumina, Inc.) according to the manufacturer's instructions. Initial microarray gene expression data were obtained using Bead Studio software with gene expression analysis module (version 3.1.3, Illumina, Inc.).

Project description:Background: Neoadjuvant chemotherapy (NAC) is the standard treatment for muscle-invasive bladder cancer (MIBC), yet 40% of patients progress, emphasizing the need for biomarkers predictive for response or chemoresistance. Gene expression-based subtypes may serve as biomarkers, though which subtypes will respond, notably when it comes to the basal subtype, remains contentious. Patients and methods: This post hoc study analyzed 300 NAC-treated patients enrolled in the GETUG/AFU VESPER trial, with transurethral diagnostic formalin-ﬁxed parafﬁn-embedded which underwent pathological review before being sequenced. ‘Mixed’ subtype was deﬁned for tumors displaying at least two different Consensus molecular subtypes in separate regions. We evaluated the association between molecular subtypes and outcome after NAC. Tumors with remaining tissue at cystectomy (n ¼ 83) were compared with pre-treatment tumors. Results: Cases were classiﬁed basal/squamous (Ba/Sq) (n ¼ 84), luminal unstable (n = 57), stroma-rich (n = 53), mixed (n = 48), luminal papillary (n ¼ 39), luminal non-speciﬁc (n = 18), and neuroendocrine-like (n ¼ 1), with 30/48 mixed cases including a Ba/Sq component. Compared with other molecular subtypes in a multivariate Cox model, Ba/Sq (pure or mixed) patients had an increased hazard ratio (HR) of progression-free survival [HR 2.0, 95% conﬁdence interval (CI) 1.36-3.0]. Mixed tumors were associated with decreased metabolic activity that could account for chemoresistance. Ba/Sq and mixed non-responders mostly maintained their subtype at cystectomy and have fewer myeloid dendritic cells after NAC. Tumors classiﬁed luminal papillary at transurethral resection of the urinary bladder tumor exhibited an increase in T CD4þ and macrophage signatures after NAC. Other subtypes did not show signiﬁcant immune changes after NAC. Our study design relied on detailed pathological review, which precluded evaluating the mixed subtype in published datasets. Furthermore, the sample size for post-NAC analyses constrained the statistical power of these ﬁndings. Conclusions: Our ﬁndings underscore the importance of recognizing intra-tumor heterogeneity in MIBC and its role in chemoresistance associated with Ba/Sq subtype, and provide valuable insights that could help future treatment development and improve patient outcomes.

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Identification of Differential Tumor Subtypes of T1 Bladder Cancer

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