Chemotherapeutic sensitivity in colorectal cancer expressing low RNA of wild type homologous recombination genes.

Authors

null

Daniel Walden

Mayo Clinic Arizona, Phoenix, AZ

Daniel Walden , Sachin Deshmukh , Felipe Batalini , Binbin Zheng-Lin , Sharon Wu , Joanne Xiu , Bennett Adam Caughey , John H Strickler , Wolfgang Michael Korn , Emil Lou , Daniel H. Ahn , Christina Wu , Sanjay Goel , Anthony F. Shields , Tanios S. Bekaii-Saab

Organizations

Mayo Clinic Arizona, Phoenix, AZ, Caris Life Sciences, Phoenix, AZ, Mayo Clinic, Phoenix, AZ, Department of Medicine, Duke University Medical Center, Durham, NC, Duke University Medical Center, Durham, NC, Caris MPI, Phoenix, AZ, University of Minnesota, Minneapolis, MN, Mayo Clinic Arizona, Scottsdale, AZ, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, Barbara Ann Karmanos Cancer Institute, Detroit, MI, Mayo Clinic Cancer Center Scottsdale, Phoenix, AZ

Research Funding

No funding received
None.

Background: Homologous recombination deficient (HRD) colorectal cancer (CRC) has improved overall survival (OS) when exposed to DNA damaging agents (DDA) oxaliplatin (OX) and irinotecan (IR). However, this OS benefit is only observed in HRD mutated CRC. Low expression of wild type (WT) BRCA1 RNA displays prolonged OS in ovarian cancer; this finding has not been investigated in CRC or outside BRCA. We investigate if low expression of WT HR genes is associated with prolonged OS in response to DDA. Methods: A total of 12,860 CRC patients tumor biopsies were analyzed by next-generation sequencing (592, NextSeq; WES, WTS NovaSeq). Patients with HRD mutations and MSI-H were excluded (N = 935). 11,925 patients were included in the analysis. A total of 11 core (BARD1, BLM, BRCA1, BRCA2, BRIP1, MRE11, NBN, PALB2, RAD50, RAD51, RAD51B) and 7 related (BAP1, WRN, DNMT3A, ERCC1, FANCA, FANCF, RECQL4) HR genes were analyzed. Samples were classified by RNA expression percentiles within the studied cohort. Real world OS was extracted from insurance claims and calculated using Kaplan-Meier estimates for molecularly defined cohorts from first of OX or IR to last contact. Results: OS benefit is seen in low RNA expression (bottom 10%) compared to high expression (top 10%) of all core WT HR genes except RAD51B, BARD1 and BRCA2 in response to IR. We observe a progressively longer OS with lower associated RNA expression in response to DDA. OS of nearly 7 years was observed in low expressing BRCA1 and RAD51 following IR exposure and 4.5-year OS benefit when compared to high expression of these genes. OS benefit in response to OX was less robust but significantly prolonged in BRCA1 and BRIP1 (Table). Patients harboring HRD mutations had similar OS to WT HR RNA low (bottom 10%) in response to OX (HR = 0.75; p = 0.1) and IR (HR = 0.82; p = 0.36). Conclusions: Here we report a novel subclass of CRC defined as patients with low RNA expressing WT HR genes that exhibit differential sensitivity to DDA. Significantly longer survival is noted in CRC with low expression BRCA1, RAD51 and BLM, while post-OX survival was significantly prolonged with low expression of BRCA1, BRIP1 and FANCA. Further characterization of sensitive HR genes will better predict DDA sensitivity and impact treatment sequencing.

Gene – DDAHRTop 10% RNABottom 10% RNAp-valGene-DDAHRTop 10% RNABottom 10% RNAp-val
BRCA1-IR0.62
25.9 m
(N = 232)
80.5 m
(N = 197)
0.009BRCA1-OX0.6640.3 m
(N = 362)
61.5 m
(N = 358)
0.005
RAD51-IR0.5526.1 m
(N = 255)
80.5 m
(N = 231)
< 0.001RAD51-OX0.6961.8 m
(N = 406)
64.7 m
(N = 420)
0.008
BLM-IR0.5026.6 m
(N = 232)
53.3 m
(N = 205)
< 0.001BLM-OX0.6650.5 m
(N = 348)
61.8 m
(N = 389)
0.008
BRIP1-IR0.6026.6 m
(N = 234)
45.0 m
(N = 211)
0.007BRIP1-OX0.6747.3 m
(N = 336)
74.9 m
(N = 381)
0.009
FANCA-IR0.6325.0 m
(N = 224)
35.3 m
(N = 194)
0.01FANCA-OX0.6441.4 m
(N = 327)
60.9 m
(N = 357)
0.004

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Gastrointestinal Cancer—Colorectal and Anal

Track

Gastrointestinal Cancer—Colorectal and Anal

Sub Track

Epidemiology/Outcomes

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 3531)

DOI

10.1200/JCO.2023.41.16_suppl.3531

Abstract #

3531

Poster Bd #

231

Abstract Disclosures

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