In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 35, No. 15_suppl ( 2017-05-20), p. 4529-4529
Abstract:
4529 Background: SCBC is rare and its underlying biology poorly understood. Molecular profiling can shed light on the biology and identify treatment targets and biomarkers. Methods: A retrospective review of 63 patients (pts) with biopsy-confirmed SCBC at Cleveland Clinic (1994-2015) was performed. Percentage of small cell component (SC%) was defined by independent pathology review. DLL3 and PD-L1 protein expression were measured by IHC in 53 pts. Gene expression analysis was done in 38 primary SCBC tumor samples, 1 metastatic sample, and 5 normal bladder tissue samples (44 total) from the same cohort using HTG EdgeSeq OBP Assay with probes for 2568 genes. Analysis was performed via the RNAseq workflow (Partek Genomics Suite). Results: Among 63 identified pts, median age was 71 (39-90), 83% were men, median SC% was 100% (range 5-100%), median follow-up was 16.6 months and estimated median overall survival (OS) was 22.8 months. Unsupervised hierarchical clustering of gene expression patterns from 44 samples produced 4 distinct clusters. Pts with tumors in cluster 1 (that also included normal samples) did not have metastasis at diagnosis or distant recurrence, both of which were over-represented in the other 3 clusters. Kaplan-Meier analysis revealed a trend towards longer OS in cluster 1 patients (log rank p = 0.065). Higher gene expression of PRC1, NCAM1 (CD56) and DLL3 correlated with higher SC%, as did lower gene expression of ERBB2, PD-L1 and HPGD (p 〈 0.01). PD-L1 protein expression (≥1% cells) was noted in 30% of pts but did not correlate with outcome, SC%, DLL3 protein expression, or PD-L1 gene expression. DLL3 protein expression (≥1% cells) was noted in 68% of pts and DLL3 〉 10% correlated with decreased OS (p = .03). Higher DLL3 protein expression correlated with DLL3 gene expression (Spearman r = 0.70, p 〈 .01) and with SC% (r = .33, p = .01). Conclusions: This is the first study to reveal distinct gene expression patterns that define aggressive behavior, metastatic potential and outcomes in SCBC. The prognostic value of differential gene expression networks and the presence of underlying genomic and epigenetic alterations is the subject of ongoing prospective validation in a larger cohort.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2017.35.15_suppl.4529
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2017
detail.hit.zdb_id:
2005181-5
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