Abstract 3423: Determining neoadjuvant cisplatin-based chemosensitivity in muscle invasive bladder cancer through differential gene and miRNA expression analysis

Abstract

Abstract Background: Muscle invasive bladder cancer (MIBC) neoadjuvant responders as opposed to nonresponders demonstrated significantly improved 5-year cancer specific survival and reduced nodal positivity rates. Identification of chemo responsive cohorts would not only facilitate targeted delivery of chemotherapy to those most likely to benefit, but also avoid morbidity and delayed surgical intervention in patients unlikely to derive benefit. We evaluated the role of gene and miRNA expression profiles in initial TURBT (transurethral resection of bladder tumor) specimens of patients before undergoing neoadjuvant chemotherapy and subsequent radical cystectomy. Pathological response at time of cystectomy was used to classify initial TURBT specimens as responders (pT0) versus non-responders (≥pT2). Differential expression of gene and miRNA between the two groups may help stratify patients being considered for neoadjuvant chemotherapy. Methods: TURBT specimens from patients with MIBC were preserved in FFPE tissue blocks before patients subsequently received cisplatin-based neoadjuvant chemotherapy. A total of 13 pT0 and 17 ≥pT2 patients were selected and matched for age, gender and tumor stage. RNA was extracted from FFPE blocks using an Ambion total nucleic acid isolation kit. mRNA was sequenced using Illumina TruSeq RNA Access Library and NextSeq technology. Gene counts were assessed by ht-seq counts and differential expression using DESeq2. Pathway analysis was performed using GAGE. Differential expression of 754 miRNAs was analyzed using the TaqMan openarray miRNA panel. Results: In responders, a gene-set enrichment analysis revealed significant upregulation of genes in the hsa00190 pathway (implicated in oxidative phosphorylation), hsa03040(spliceosome function). In non-responders, there was significant upregulation of genes in the hsa04510 pathway (focal adhesion), hsa04512 (ECM-receptor interaction), hsa04310(Wnt signaling), hsa04350(TGF-beta signaling) and hsa04010 (MAPK signaling). For the miRNA analysis, significant upregulation of miR-23a, miR-27a, miR-135b, miR-145, miR-422a was seen in responders, and miR-93, miR-107, miR-339-3p, miR-532 in non-responders. Using a random forest classification, a significant proportion of non-responders were correctly identified compared to responders. Conclusion: Gene and miRNA expression in initial MIBC TURBT specimens may be used as an aid in predicting neoadjuvant non-responders. Increasing the sample size is needed to further validate our findings and may lead to a successful chemotherapy prediction model. Citation Format: Neal Murphy*, Paras Shah*, Annette Lee, Thomas Bradley, Manish Vira, Ilya Korsunsky, Andrew Shih, Oksana Yaskiv, Zachary Kozel, Anthony Liew, Houman Khalili, Xinhua Zhu. Determining neoadjuvant cisplatin-based chemosensitivity in muscle invasive bladder cancer through differential gene and miRNA expression analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3423.