BRAF, NRAS and KIT sequencing analysis of spindle cell melanoma.
BACKGROUND
Spindle cell melanoma represents a rare but distinct subset of melanoma, and its genomic spectrum has not been fully defined.


METHODS
We searched our institutional database for patients with a diagnosis of pure spindle cell-type melanoma whose tumors had been analyzed for BRAF, NRAS, and KIT mutations using pyrosequencing technique.


RESULTS
We identified 24 patients with spindle cell melanoma, including 10 patients with desmoplastic melanoma, whose tumors had been analyzed for at least one of the three genes. The median Breslow thickness was 2.6 mm, and the most common site of the primary melanoma was the trunk, followed by the head and neck region. BRAF, NRAS and KIT genomic sequencing was performed successfully in 20, 18 and 14 patients, respectively. Among the 20 melanomas with completed BRAF-sequencing analysis, 6 (30%) harbored a mutation, of which 5 (83%) had a V600E mutation and 1 (17%) had a V600R mutation. None of the melanomas harbored NRAS or KIT mutations.


CONCLUSIONS
As has been reported in other common types of melanoma, V600 BRAF mutation is the most common mutation of those tested in spindle cell melanoma. NRAS or KIT mutation appears to be rare, if not completely absent.
Department of Melanoma Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Jinhyun
J
Kim
Alexander J
AJ
Lazar
Michael A
MA
Davies
Jade
J
Homsi
Nicholas E
NE
Papadopoulos
Wen-Jen
WJ
Hwu
Agop Y
AY
Bedikian
Scott E
SE
Woodman
Sapna P
SP
Patel
Patrick
P
Hwu
Kevin B
KB
Kim
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004252:DNA Mutational Analysis; D005260:Female; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008545:Melanoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D009154:Mutation; D015689:Oncogene Protein p21(ras) / Q000235:genetics* / Q000378:metabolism; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics* / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism; D012878:Skin Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
D019009:Proto-Oncogene Proteins c-kit; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D015689:Oncogene Protein p21(ras)