Neuroblastoma RAS viral oncogene homolog (G12V variant) (NRAS G12V)

Neuroblastoma RAS viral oncogene homolog (NRAS) is a small GTPase that acts as a critical molecular switch in cellular signaling, alternating between an active GTP-bound state and an inactive GDP-bound state. The G12V variant is a common oncogenic mutation where glycine at position 12 is replaced by valine, a change that severely impairs GTP hydrolysis and locks the protein in a constitutively active conformation. This persistent activity drives aggressive cell proliferation and survival through the MAP kinase and PI3K pathways, contributing significantly to the pathogenesis of melanoma, colorectal cancer, and various leukemias. In clinical practice, NRAS G12V status is a vital biomarker, as its presence predicts poor response to EGFR-targeted monoclonal antibodies like cetuximab in colorectal cancer patients. While direct selective inhibitors for this specific variant are still largely in the developmental or clinical trial stages (such as pan-RAS inhibitors like RMC-6236), current management often relies on downstream inhibition of the MEK protein. Emerging strategies also include immunotherapeutic approaches such as TCR-engineered T-cell therapies designed to recognize the G12V neoantigen.

Other names

NRAS p.G12VNRAS p.Gly12ValNRAS Gly12ValNRAS G12V mutantN-ras G12VG12V mutant NRAS

The NRAS G12V mutation results in a single amino acid substitution (Glycine to Valine at position 12), which impairs the protein's intrinsic GTPase activity and renders it insensitive to GTPase-activating proteins (GAPs). This leads to the accumulation of NRAS in its active GTP-bound 'ON' state, resulting in constitutive activation of downstream signaling pathways, primarily the MAPK/ERK and PI3K/AKT cascades, which drive uncontrolled cell growth and survival. Therapeutic approaches include the use of MEK inhibitors to block downstream signaling or pan-RAS(ON) inhibitors that non-covalently bind the active state to disrupt effector interaction.