Tilman Todenhöfer

Impact of Molecular Subtypes in Muscle-invasive Bladder Cancer on Predicting Response and Survival after Neoadjuvant Chemotherapy

BACKGROUND An early report on the molecular subtyping of muscle-invasive bladder cancer (MIBC) by gene expression suggested that response to neoadjuvant chemotherapy (NAC) varies by subtype. OBJECTIVE To investigate the ability of molecular subtypes to predict pathological downstaging and survival after NAC. DESIGN, SETTING, AND PARTICIPANTS Whole transcriptome profiling was performed on pre-NAC transurethral resection specimens from 343 patients with MIBC. Samples were classified according to four published molecular subtyping methods. We developed a single-sample genomic subtyping classifier (GSC) to predict consensus subtypes (claudin-low, basal, luminal-infiltrated and luminal) with highest clinical impact in the context of NAC. Overall survival (OS) according to subtype was analyzed and compared with OS in 476 non-NAC cases (published datasets). INTERVENTION Gene expression analysis was used to assign subtypes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Receiver-operating characteristics were used to determine the accuracy of GSC. The effect of GSC on survival was estimated by Cox proportional hazard regression models. RESULTS AND LIMITATIONS The models generated subtype calls in expected ratios with high concordance across subtyping methods. GSC was able to predict four consensus molecular subtypes with high accuracy (73%), and clinical significance of the predicted consensus subtypes could be validated in independent NAC and non-NAC datasets. Luminal tumors had the best OS with and without NAC. Claudin-low tumors were associated with poor OS irrespective of treatment regimen. Basal tumors showed the most improvement in OS with NAC compared with surgery alone. The main limitations of our study are its retrospective design and comparison across datasets. CONCLUSIONS Molecular subtyping may have an impact on patient benefit to NAC. If validated in additional studies, our results suggest that patients with basal tumors should be prioritized for NAC. We discovered the first single-sample classifier to subtype MIBC, which may be suitable for integration into routine clinical practice. PATIENT SUMMARY Different molecular subtypes can be identified in muscle-invasive bladder cancer. Although cisplatin-based neoadjuvant chemotherapy improves patient outcomes, we identified that the benefit is highest in patients with basal tumors. Our newly discovered classifier can identify these molecular subtypes in a single patient and could be integrated into routine clinical practice after further validation.

Development of a new outcome prediction model in carcinoma invading the bladder based on preoperative serum C‐reactive protein and standard pathological risk factors: the TNR‐C score

Study Type – Prognosis (case series)

Continuous Flow Deformability‐Based Separation of Circulating Tumor Cells Using Microfluidic Ratchets

Circulating tumor cells (CTCs) offer tremendous potential for the detection and characterization of cancer. A key challenge for their isolation and subsequent analysis is the extreme rarity of these cells in circulation. Here, a novel label-free method is described to enrich viable CTCs directly from whole blood based on their distinct deformability relative to hematological cells. This mechanism leverages the deformation of single cells through tapered micrometer scale constrictions using oscillatory flow in order to generate a ratcheting effect that produces distinct flow paths for CTCs, leukocytes, and erythrocytes. A label-free separation of circulating tumor cells from whole blood is demonstrated, where target cells can be separated from background cells based on deformability despite their nearly identical size. In doping experiments, this microfluidic device is able to capture >90% of cancer cells from unprocessed whole blood to achieve 10(4) -fold enrichment of target cells relative to leukocytes. In patients with metastatic castration-resistant prostate cancer, where CTCs are not significantly larger than leukocytes, CTCs can be captured based on deformability at 25× greater yield than with the conventional CellSearch system. Finally, the CTCs separated using this approach are collected in suspension and are available for downstream molecular characterization.

AR-V7 Transcripts in Whole Blood RNA of Patients with Metastatic Castration Resistant Prostate Cancer Correlate with Response to Abiraterone Acetate

Purpose: The expression of AR‐V7 (androgen receptor splice variant) 7 in circulating tumor cells has been associated with resistance to abiraterone and enzalutamide in patients with metastatic castration resistant prostate cancer. We used a sensitive, whole blood reverse transcriptase‐polymerase chain reaction assay that does not require circulating tumor cell enrichment to correlate outcomes of abiraterone with whole blood expression of AR‐V7 and other prostate cancer associated transcripts. Materials and Methods: We assessed the expression of AR‐V7, FOXA1, GRHL2, HOXB13, KLK2, KLK3 and TMPRSS2:ERG mRNA in 2.5 ml whole blood from each of 27 patients with metastatic castration resistant prostate cancer and 33 controls without cancer as the discovery cohort. Cycle threshold values of controls with the highest gene expression were set as the threshold for a positive test. Thresholds were then applied to a validation cohort of 37 patients with metastatic castration resistant prostate cancer who were commencing abiraterone. Gene expression was correlated with the prostate specific antigen response rate using the chi‐square test, and with time to prostate specific antigen progression and overall survival using the log rank test. Results: In the discovery cohort 3 of 27 patients (11.1%) with metastatic castration resistant prostate cancer were AR‐V7 positive vs 4 of 37 (10.8%) in the validation cohort. In the validation cohort patients with a positive AR‐V7 test had a lower prostate specific antigen response rate (0% vs 42%, p = 0.27) together with shorter median prostate specific antigen progression (0.7 vs 4.0 months, p <0.001) and median overall survival (5.5 vs 22.1 months, p <0.001). Conclusions: Reverse transcriptase‐polymerase chain reaction detection of AR‐V7 transcripts in whole blood was associated with inferior outcomes in patients treated with abiraterone. These results reinforce the potential usefulness of AR‐V7 as a prognostic and predictive biomarker for metastatic castration resistant prostate cancer.

Thymidine kinase and cancer monitoring

Thymidine kinases (TK) have a key function in the synthesis of DNA. Two isoenzymes have been characterized: TK1 is cell cycle-dependent and present in the cytoplasm whereas TK2--located in mitochondria--is cell cycle-independent. The diagnostic and prognostic role of TK1 has recently been investigated. TK1 might be helpful for screening and monitoring of human malignancies. TK1 may also serve as a prognostic factor for progression. Herein, we summarize the status of TK1 for cancer monitoring and point out its use as a proliferation marker. A comprehensive overview about the association of TK-1 with various entities is given.

A new prognostic model for cancer-specific survival after radical cystectomy including pretreatment thrombocytosis and standard pathological risk factors

Study Type – Prognosis (cohort series)

Current status of molecular markers for prognostication and outcome in invasive bladder cancer

Whats known on the subject? and What does the study add?

Insulin Receptor Isoforms A and B as well as Insulin Receptor Substrates-1 and -2 Are Differentially Expressed in Prostate Cancer

Aims/Hypothesis In different cancers types, insulin receptor isoform composition or insulin receptor substrate (IRS) isoforms are different to healthy tissue. This may be a molecular link to increased cancer risk in diabetes and obesity. Since this is yet unclear for prostate cancer, we investigated IR isoform composition and IRS balance in prostate cancer compared to benign and tumor adjacent benign prostate tissue and brought this into relation to cell proliferation. Methods We studied 23 benign prostate samples from radical cystectomy or benign prostatic hyperplasia surgery, 30 samples from benign tissue directly adjacent to prostate cancer foci and 35 cancer samples from different patients. RNA expression levels for insulin receptor isoforms A and B, IRS-1, IRS-2, and IGF-1 receptor were assessed by quantitative real-time RT-PCR. In addition, RNA- and protein expression of the cell cycle regulator p27Kip1 was quantified by real-time RT-PCR and immunohistochemistry. Results Insulin receptor isoform A to B ratio was significantly higher in cancer as well as in tumor adjacent benign prostate tissue compared to purely benign prostates (p<0.05). IRS-1 to IRS-2 ratios were lower in malignant than in benign prostatic tissue (p<0.05). These altered ratios both in cancer and adjacent tissue were significantly associated with reduced p27Kip1 content (p<0.02). Interestingly, IGF-1 receptor levels were significantly lower in patients with type 2 diabetes (p = 0.0019). Conclusions/Interpretation We found significant differences in the insulin signaling cascade between benign prostate tissue and prostate cancer. Histological benign tissue adjacent to cancer showed expression patterns similar to the malignancies. Our findings suggest a role of the insulin signaling pathway in prostate cancer and surrounding tissue and can hence be relevant for both novel diagnostic and therapeutic approaches in this malignancy.

The prognostic value of hematological and systemic inflammatory disorders in invasive bladder cancer.

Purpose of review In contrast to the large amount of evidence reporting on the oncological significance of various clinicopathological and molecular parameters for survival in invasive bladder cancer, alterations of preoperative hematological and systemic inflammatory parameters have not been sufficiently addressed in the literature so far. Recent findings Pretreatment serum C-reactive protein was recently incorporated in a new outcome prediction model, termed Tumor Node Resection C-reactive protein score, and demonstrated a significant increase in the predictive accuracy of standard pathologic risk factors for cancer-specific survival after radical cystectomy. The presence of preoperative thrombocytosis is associated with multiple hematologic disorders in invasive bladder cancer and higher tumor aggressiveness suggesting that platelets play a role in tumor growth and metastasis formation. In patients undergoing second-line chemotherapy for metastatic disease, pretreatment lower hemoglobin level was identified as an independent prognostic factor for overall survival. Summary The degree of systemic inflammation and hematological disorders in invasive bladder cancer is often associated with more aggressive disease. The incorporation of hemoglobin levels, serum C-reactive protein and platelet counts into current nomograms might improve significantly the predictive accuracy of standard clinicopathological risk factors and provide improved prognostication for counseling more selectively the use of chemotherapy in the neoadjuvant, adjuvant and metastatic setting.

Combined application of cytology and molecular urine markers to improve the detection of urothelial carcinoma

The sensitivity of cytology for the detection of urothelial carcinoma (UC) is limited. Newer methods such as fluorescence in situ hybridization (FISH), immunocytology (uCyt+), and protein markers have been developed to improve urine‐based detection of UC. As only little is known regarding the combined application of these markers, we investigated whether combinations of 4 of the most broadly available tests (cytology, FISH, uCyt+, and nuclear matrix protein 22 [NMP22‐ELISA]) may improve their diagnostic performance.