In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 37, No. 7_suppl ( 2019-03-01), p. 371-371
Abstract:
371 Background: Although the genomic landscape of LTUC is well studied, less is known about UTUC, including in the metastatic sites. We compared genomic features of metastatic UTUC and LTUC. Methods: We performed whole exome sequencing on 7 rapid autopsy patients with metastatic UC, with matched primary and metastatic tumor samples (N = 37). Single nucleotide variants (SNV) were identified using Mutect and Strelka. Focused analyses were performed on mutations with known significance in UC as well as mutations predicted to have functional impact using 11 mutation assessors. Genome scale copy number aberrations (CNA) were estimated using Sequenza (normalized for ploidy) to derive gene definition restricted copy number estimation outcomes. Multi-dimensional scaling (MDS) was used to visualize how copy number and mutation-derived genomic distances differed between LTUC and UTUC. Results: Three pts with UTUC (3 primary samples, 13 metastases) and four pts with LTUC (4 primary samples, 17 metastases) were examined. The majority of patients were male (5) and received cisplatin-based therapy (5). We found that SNV burden (mean mutation per megabase) was significantly higher in LTUC vs. UTUC overall (6.6 vs. 3.8, p = 0.001) and when stratified by primaries (6.1 vs. 2.9, p = 0.047); or metastases (6.7 vs. 4.1, p = 0.001). Mutational signature analysis revealed higher proportion of APOBEC signature in all LTUC vs. UTUC tumors. Both inter- and intra-individual genomic distances between primary and metastatic tissues were substantially larger in UTUC than LTUC, suggesting a wider spectrum of mutations at the level of individual nucleotides and chromosomal structure. Interestingly, Gene definition-restricted CNA analysis revealed MDM2 amplification exclusively in UTUC tumors which was associated with shallow p53 deletion. Conclusions: Metastatic UTUC appears to have a lower overall mutational burden but greater genomic variability compared to LTUC. Our relatively small dataset suggests that metastatic UTUC displays a greater spectrum of mutational divergence from LTUC which may partially explain differences in clinical behavior.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/JCO.2019.37.7_suppl.371
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2019
detail.hit.zdb_id:
2005181-5
