Volume 153, Issue 3 pp. 571-583
CANCER GENETICS AND EPIGENETICS

Mutational evolution after chemotherapy-progression in metastatic colorectal cancer revealed by circulating tumor DNA analysis

Sheehyun Kim

Sheehyun Kim

Department of Genomic Medicine, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Yongjun Cha

Yongjun Cha

Center for Colorectal Cancer, National Cancer Center, Research Institute and Hospital, Goyang, South Korea

Search for more papers by this author
Yoojoo Lim

Yoojoo Lim

Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Hanseong Roh

Hanseong Roh

IMBdx, Inc., Seoul, South Korea

Search for more papers by this author
Jun-Kyu Kang

Jun-Kyu Kang

IMBdx, Inc., Seoul, South Korea

Search for more papers by this author
Kyung-Hun Lee

Kyung-Hun Lee

Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea

Cancer Research Institute, Seoul National University, Seoul, South Korea

Search for more papers by this author
Min Jung Kim

Min Jung Kim

Department of Surgery, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Ji Won Park

Ji Won Park

Department of Surgery, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Seung-Bum Ryoo

Seung-Bum Ryoo

Department of Surgery, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Hwang-Phill Kim

Hwang-Phill Kim

IMBdx, Inc., Seoul, South Korea

Search for more papers by this author
Seung-Yong Jeong

Seung-Yong Jeong

Department of Surgery, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Kyu Joo Park

Kyu Joo Park

Department of Surgery, Seoul National University Hospital, Seoul, South Korea

Search for more papers by this author
Sae-Won Han

Corresponding Author

Sae-Won Han

Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea

Cancer Research Institute, Seoul National University, Seoul, South Korea

Correspondence

Sae-Won Han, Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, South Korea.

Email: [email protected]

Search for more papers by this author
Tae-You Kim

Tae-You Kim

Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea

IMBdx, Inc., Seoul, South Korea

Cancer Research Institute, Seoul National University, Seoul, South Korea

Search for more papers by this author
First published: 16 May 2023

Sheehyun Kim and Yongjun Cha contributed equally to this work.

Abstract

Emerging new mutations after treatment can provide clues to acquired resistant mechanisms. Circulating tumor DNA (ctDNA) sequencing has enabled noninvasive repeated tumor mutational profiling. We aimed to investigate newly emerging mutations in ctDNA after disease progression in metastatic colorectal cancer (mCRC). Blood samples were prospectively collected from mCRC patients receiving palliative chemotherapy before treatment and at radiological evaluations. ctDNA from pretreatment and progressive disease (PD) samples were sequenced with a next-generation sequencing panel targeting 106 genes. A total of 712 samples from 326 patients were analyzed, and 381 pretreatment and PD pairs (163 first-line, 85 second-line and 133 later-line [≥third-line]) were compared. New mutations in PD samples (mean 2.75 mutations/sample) were observed in 49.6% (189/381) of treatments. ctDNA samples from later-line had more baseline mutations (P = .002) and were more likely to have new PD mutations (adjusted odds ratio [OR] 2.27, 95% confidence interval [CI]: 1.40-3.69) compared to first-line. RAS/BRAF wild-type tumors were more likely to develop PD mutations (adjusted OR 1.87, 95% CI: 1.22-2.87), independent of cetuximab treatment. The majority of new PD mutations (68.5%) were minor clones, suggesting an increasing clonal heterogeneity after treatment. Pathways involved by PD mutations differed by the treatment received: MAPK cascade (Gene Ontology [GO]: 0000165) in cetuximab and regulation of kinase activity (GO: 0043549) in regorafenib. The number of mutations revealed by ctDNA sequencing increased during disease progression in mCRC. Clonal heterogeneity increased after chemotherapy progression, and pathways involved were affected by chemotherapy regimens.

Graphical Abstract

What's new?

Mutations that arise during treatment for metastatic colorectal cancer (mCRC) can fuel the development of treatment-resistant tumors. Tracking the mutational evolution of mCRC, however, is challenged by limitations in existing approaches. Here, the authors investigated newly emerging mutations by sequencing circulating tumor DNA (ctDNA) from progressive mCRC patients following conventional treatments. Mutations that emerged in association with treatment were identified in half of progressive disease samples. New mutations were dominantly subclonal variants and were more frequently observed in later-line treatments and RAS/BRAF wild-type tumors. The findings cast new light on relationships between emergent mutations and treatment in progressive mCRC.

CONFLICT OF INTEREST STATEMENT

Yongjun Cha received consulting fees from IMBdx; Yoojoo Lim, Hanseong Roh and Jun-Kyu Kang are employees of IMBdx; Hwang-Phill Kim is an employee and stock owner of IMBdx; Sae-Won Han received honoraria and a research fund from IMBdx and Tae-You Kim is a co-founder and stock owner of IMBdx. The other authors declare no competing interest.

DATA AVAILABILITY STATEMENT

All the NGS data of ctDNA sequencing are available on the NCBI Sequence Read Archive (SRA) database with links to BioProject (https://www.ncbi.nlm.nih.gov/bioproject/) accession number PRJNA933526. The data that support the findings of our study are available from the corresponding author upon reasonable request.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.