NRAS A146T

In this cohort with population-based and real-world patients, no differences in patient characteristics or treatment modalities were seen between different RAS mt, except a higher frequency of right-colon primaries among KRAS mt compared with NRAS mt. KRAS -G12S conferred a worse OS compared with some other KRAS mt, whereas no other differences in OS were seen. It therefore seems as if different RAS mt behave quite similar.

P2 | "According to liquid biopsy before second- and third-line therapies, treatment sequences are: FOLFIRI + cetuximab (first-line), FOLFOX + cetuximab (second-line); irinotecan + cetuximab (third-line) in patients with plasma ctDNA RAS/BRAFV600E WT tumors. In patients with RAS/BRAFV600E mutant tumors, second-line is FOLFOX + bevacizumab, while third-line is regorafenib or trifluridine/tipiracil (investigator's choice)... Both tumor tissue- and liquid biopsy-based comprehensive genomic profiling by NGS identify additional molecular alterations, that could be involved in resistance to anti-EGFR monoclonal antibodies, as compared to PCR-based tumor tissue analysis. CAPRI 2-GOIM trial will determine if NGS would allow better selection of RAS/BRAFV600E WT mCRC patients for the most appropriate treatments through three sequential lines of therapies."

KRAS mutated CRC patients in North Africa have been identified with incidence closer to the European figures. Beside established anti-CRC treatment, better understanding of the causality of CRC can be established by combining epidemiology and genetic/epigenetic on CRC etiology. This approach may be able to significantly reduce the burden of CRC in North Africa.

However, we also found mutations that are specific for one sister cell line only, pointing to individual subclones of the primary tumor as originating cells. Our data show that sequential sister cell lines can be used to study the clonal development of tumors and to elucidate the function of common and clone-specific mutations.

We report the NRAS mutation is common in cutaneous RDD, and NRAS A146T was the most frequent mutation in this cohort. Mutations in the NRAS gene can activate the RAS/MAPK signaling and have been reported to be associated with various cancers. It indicates that NRAS mutation in MAPK/ERK pathway may involve the pathogenesis of cutaneous RDD.

Notably, leukemias and MPDs frequently have mutations in KRAS and NRAS at either codon 12 or 61. Our GEMMs recapitulate the tissue-specificity of RAS mutations observed in patients and highlight the unique oncogenic activity of KrasQ61R.

In addition, this shows that high p53 expression in the pretreatment biopsy was associated with an incomplete response in surgical resection specimens after neoadjuvant treatment, and a HER-2 score 3+ can be a predictive factor of distant metastasis and local recurrence. Larger, prospective, and more studies are needed.

Legal entity responsible for the study The author. Funding Has not received any funding.