Frequent mutations in the MITF pathway in melanoma.
Microphthalmia-associated transcription factor (MITF) is involved in melanocyte cell development, pigmentation and neoplasia. To determine whether MITF is somatically mutated in melanoma, we compared the sequence of MITF from primary and metastatic lesions to patient-matched normal DNA. In the 50 metastatic melanoma tumor lines analysed, we discovered four samples that had genomic amplifications of MITF and four that had MITF mutations in the regions encoding the transactivation, DNA binding or basic, helix-loop-helix domains. Sequence analysis for SOX10, a transcription factor, which both acts upstream of MITF and synergizes with MITF, identified an additional three samples with frameshift or nonsense mutations. Microphthalmia-associated transcription factor and SOX10 were found to be mutated in a mutually exclusive fashion, possibly suggesting disruption in a common genetic pathway. Taken together we found that over 20% of the metastatic melanoma cases had alterations in the MITF pathway. We show that the MITF pathway is also altered in primary melanomas: 2/26 demonstrated mutations in MITF and 6/55 demonstrated mutations in SOX10. Our findings suggest that altered MITF function during melanomagenesis can be achieved by MITF amplification, MITF single base substitutions or by mutation of its regulator SOX10.
National Human Genome Research Institute, Bethesda, MD, USA.
Julia C
JC
Cronin
John
J
Wunderlich
Stacie K
SK
Loftus
Todd D
TD
Prickett
Xiaomu
X
Wei
Katie
K
Ridd
Swapna
S
Vemula
Allison S
AS
Burrell
Neena S
NS
Agrawal
Jimmy C
JC
Lin
Carolyn E
CE
Banister
Phillip
P
Buckhaults
Steven A
SA
Rosenberg
Boris C
BC
Bastian
William J
WJ
Pavan
Yardena
Y
Samuels
D045744:Cell Line, Tumor; D018389:Codon, Nonsense; D016368:Frameshift Mutation; D011905:Genes, ras / Q000502:physiology; D006801:Humans; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D009362:Neoplasm Metastasis; D048493:Proto-Oncogene Proteins B-raf / Q000378:metabolism; D055757:SOXE Transcription Factors / Q000235:genetics / Q000502:physiology; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
D018389:Codon, Nonsense; D051739:Microphthalmia-Associated Transcription Factor; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf