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Comparison of KRAS status between primary colorectal tumor and metastasis or recurrent tumor
Previous NGS experiments showed that distinct parts of the same tumor showed different mutation profiles. Additionally, primary tumors and their metastases can differ in their mutational pattern. In this study, we compare KRAS mutation status between colorectal primary cancer tissue and recurrent/metastatic sites.
Four patients with metastatic colorectal adenocarcinoma were screened for KRAS mutations by Idylla automated testing on two different tissues belonging to the same patient before treatment (primary tumor vs. metastatic/ 2 different primary site sections/ primary tumor vs. recurrent tumor).
KRAS screening showed perfect concordance in 2 patients (G12 mutation and KRASwtrespectively). One patient had a KRAS mutation in codon 146 in a colon primary tumor and no mutation in recurrent tumor tissue, nor in nodule metastases. Another patient has no mutation in the primary sigmoid tumor and a K117N KRAS mutation on the liver metastasis biopsy.
Even if high concordance is noted between primary and metastatic tumors for the KRAS mutation according to literature, passenger mutations could change the deal, and primary tumor tissue will not be sufficient for a therapeutic decision.
The authors.
Has not received any funding.
All authors have declared no conflicts of interest.
