Familial gastrointestinal stromal tumor syndrome: phenotypic and molecular features in a kindred.
OBJECTIVE
Members of a family with hereditary gastrointestinal stromal tumors (GISTs) and a germline KIT oncogene mutation were evaluated for other potential syndrome manifestations. A tumor from the proband was analyzed to compare features with sporadic GISTs.


METHODS
Members of a kindred in which six relatives in four consecutive generations comprised an autosomal dominant pattern of documented GISTs and cutaneous lesions underwent physical examination, imaging studies, and germline KIT analysis. A recurrent GIST from the proband was studied using microarray, karyotypic, immunohistochemical, and immunoblotting techniques.


RESULTS
In addition to evidence of multiple GISTs, lentigines, malignant melanoma, and an angioleiomyoma were identified in relatives. A previously reported gain-of-function missense mutation in KIT exon 11 (T --> C) that results in a V559A substitution within the juxtamembrane domain was identified in three family members. The proband's recurrent gastric GIST had a 44,XY-14,-22 karyotype and immunohistochemical evidence of strong diffuse cytoplasmic KIT expression without expression of actin, desmin, or S-100. Immunoblotting showed strong expression of phosphorylated KIT and downstream signaling intermediates (AKT and MAPK) at levels comparable with those reported in sporadic GISTs. cDNA array profiling demonstrated clustering with sporadic GISTs, and expression of GIST markers comparable to sporadic GISTs.


CONCLUSIONS
These studies provide the first evidence that gene expression and mechanisms of cytogenetic progression and cell signaling are indistinguishable in familial and sporadic GISTs. Current investigations of molecularly targeted therapies in GIST patients provide opportunities to increase the understanding of features of the hereditary syndrome, and risk factors and molecular pathways of the neoplastic phenotypes.
Li
Frederick P
FP
Dana-Farber Cancer Institute, 44 Binney St, Boston, MA 02115, USA. fli@partners.org
Fletcher
Jonathan A
JA
Heinrich
Michael C
MC
Garber
Judy E
JE
Sallan
Stephen E
SE
Curiel-Lewandrowski
Clara
C
Duensing
Anette
A
van de Rijn
Matt
M
Schnipper
Lowell E
LE
Demetri
George D
GD
D000328:Adult; D000368:Aged; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000235:genetics* / Q000473:pathology*; D020869:Gene Expression Profiling; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D010375:Pedigree; D010808:Physical Examination; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D015398:Signal Transduction; D013577:Syndrome
D019009:Proto-Oncogene Proteins c-kit