Table 5.

KIT aberrations in melanoma subtype

SubtypeKIT mutationDomain affectedIncresed KIT copy number (no./total)aCD117 expression (no./total)b
AcralV489I; E490G; Y553N; I563V; W582stop; N566D + A829V; L576P; L576F + A636A; E633G; L637L + G648S; K642E; I817T; N822K; C844Y; F848L; W853stop; L859P + L865LECD; JMD; kinase; JMD + kinase3/238/23
MucosalQ556R; W557R; V559A; V560D; E561G; I571-L576del; L576P; E583G; K642E; L647F; I789T; D816N; N822K; N822Y; W853stopJMD; kinase1/1611/16
CSDV555I; I571M; K642E; L656R; Y846H; E849stopJMD; kinase1/61/6
Non-CSDP551L; I571-L576del; T632I+L637F; K642E; L831PJMD; kinase0/53/5
UPL576P; L576F; P577H; S645NJMD; kinase0/41/4

aThe threshold for KIT gene copy number increase was 3.40 copies of KIT relative to RNase P. “No/total” indicates for number of cases with increased KIT copy number to that of cases with KIT mutation.

bThe signal intensity of immunohistochemistry results were determined by 3 individual pathologists and scored as 0, 1, 2, and 3. Samples with signal intensity of scores 1, 2, or 3 were regarded as CD117 positive. “No/total” indicates for number of cases positive for CD117 to that of cases with KIT mutation.