Abstract 3182
Background
Clonal hematopoiesis (CH) leads to blood-derived somatic mutations in KRAS, NRAS and BRAF. Our aim is to identify the prevalence of CH-derived mutations in these three genes in metastatic colorectal cancer (mCRC) patients and reveal the practical clinical implication of these mutations on plasma cell-free DNA (cfDNA) genotyping.
Methods
We analyzed KRAS, NRAS and BRAF genotypes in plasma and matched tumor tissues of 236 mCRC patients through next-generation sequencing (NGS). Suspected CH mutations were defined as those only present in plasma with variant allelic frequencies (AFs) <5% and were confirmed by paired peripheral blood cells (PBCs) using droplet digital PCR (ddPCR). The hemopoietic lineage harboring a CH-derived mutation was analyzed through flow cytometry.
Results
We identified suspected CH mutations in twenty patients (8.4%, 20/236). Three of these patients (1.27%, 3/236) had a CH-derived KRAS mutation. Two of them had a KRAS G12X and the third had a KRAS Q61H. We did not detect CH-derived NRAS or BRAF mutations. Patients harboring a CH-derived mutation previously received chemotherapy treatment. In one CH-derived KRAS G12X case, the mutation was enriched in lymphocytes and persisted in cfDNA over the course of 4 months of therapy.
Conclusions
We confirmed the existence of CH-derived KRAS mutations in a small proportion of mCRC patients. This should be noted to prevent misclassification as tumor somatic mutations when performing cfDNA sequencing.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
The National Natural Science Foundation of China (81572064, 81772263, 81772511, 81602038), the Key Developing Disciplines of Shanghai Municipal Commission of Health and Family Planning (2015ZB0201), the Projects from the Shanghai Science and Technology Commission (16411952100), the Projects from Zhongshan Hospital, Fudan University (2018ZSLC05).
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
733 - Clinical experience: ramucirumab with FOLFIRI/XELIRI as a second line for patients with metastatic gastric cancer
Presenter: Tatiana Titova
Session: Poster Display session 2
Resources:
Abstract
2186 - Efficacy and safety of apatinib for the treatment of AFP-producing gastric cancer
Presenter: Ningning Li
Session: Poster Display session 2
Resources:
Abstract
3172 - Apatinib in combination with docetaxol and S1 chemotherapy in the first line treatment of metastatic gastric cancer
Presenter: Ling Xia
Session: Poster Display session 2
Resources:
Abstract
3982 - Parameters of local cellular immunity in metastatic gastric cancer
Presenter: Aleksandr Sagakyants
Session: Poster Display session 2
Resources:
Abstract
5102 - Germline pathogenic mutations in Chinese patients with gastric cancer identified by next-generation sequencing (NGS)
Presenter: Xiaotian Zhang
Session: Poster Display session 2
Resources:
Abstract
5012 - Inhibition of the PI3K pathway in HER2-positive gastric cancer
Presenter: Sinead Toomey
Session: Poster Display session 2
Resources:
Abstract
4803 - Investigation on gastric cancer susceptibility genes in Chinese early-onset diffuse gastric cancer
Presenter: Yi Feng
Session: Poster Display session 2
Resources:
Abstract
4778 - A correlation analysis between survival rate and the characteristic gene of gastric cancer based on bioinformatics analysis
Presenter: Yi-wen Zhang
Session: Poster Display session 2
Resources:
Abstract
4805 - Phase I study of apatinib combined with POF (paclitaxel plus FOLFOX) in patients (pts) with treatment-naïve advanced gastric cancer (TNAGC)
Presenter: Rongbo LIN
Session: Poster Display session 2
Resources:
Abstract
3248 - Second-line palliative systemic treatment for synchronous metastatic esophagogastric cancer: a population-based study
Presenter: Willemieke Dijksterhuis
Session: Poster Display session 2
Resources:
Abstract