Somatic mutations in the GNAQ gene at codon 209, resulting in constitutive activation of GNAQ, were detected in 7/19 (37%) tumors, including 6/12 melanocytomas, 0/3 intermediate-grade melanocytomas, and 1/4 melanomas.
The results of this study suggest that GNAQ mutated uveal melanomas do not exhibit a higher deregulation of proliferation or higher activation of the MAPK signalling pathway than uveal melanomas without GNAQ overactivation.
Somatic GNAQ mutations at codon 209 have been identified in approximately 50% of uveal melanomas and have been reported to be oncogenic through activating PLCβ/PKC/Erk1/2 pathways.
The mutations, such as those in NRAS, BRAF, GNAQ and GNA11, promote the growth of melanoma cells in most part through the mitogen-activated protein kinase (MAPK) pathway.
Deep sequencing studies show that 4.2% of tumours carry activating mutations in GNAS (encoding Gαs), and that oncogenic activating mutations in genes encoding Gαq family members (GNAQ or GNA11) are present in ~66% and ~6% of melanomas arising in the eye and skin, respectively.
GNAQ mutations are present in uveal melanocytomas and in a case of transformation to melanoma, implicating GNAQ-dependent mitogen activation signals, in the pathogenesis of uveal melanocytoma.
These G-alpha protein mutations occur in the genes GNAQ and GNA11 and are seen at a high frequency in uveal melanomas, those melanomas that begin in the eye.
To examine whether GNAQ and GNA11 somatic mutations previously identified in uveal melanomas of Caucasians are associated with uveal melanomas in Chinese patients.