Keeping an Eye on Ocular Melanoma

Although mutations in BRAF and NRAS — which affect signaling in the MAP kinase pathway — are frequently found in common cutaneous melanomas, the molecular basis for other melanocytic tumors is still unknown. The driving force behind ocular melanomas and some intradermal melanocytic proliferations, which do not show BRAF or NRAS mutations, has not yet been identified. A few years ago, mice with germline activating mutations of the G protein GNAQ gene were found to harbor increased numbers of intradermal melanocytes, resulting in a hyperpigmentation phenotype. Investigators made use of this observation to study other, less common pigmented tumors.

These researchers found GNAQ mutations in 24 of 29 blue nevi, 1 of 2 malignant blue nevi, and 22 …