Prognosis and predictive value of KIT exon 11 deletion in GISTs.
BACKGROUND
KIT exon 11 mutations are observed in 60% of gastrointestinal stromal tumours (GIST). Exon 11 codes for residues Tyr568 and Tyr570, which play a major role in signal transduction and degradation of KIT. Our aim was to compare the outcome of patients with deletion of both Tyr568-570 (delTyr) and the most frequent deletion delWK557-558 (delWK).


METHODS
Pathology and clinical characteristics of 68 patients with delTyr (n=26) or delWK (n=42) were reviewed and compared.


RESULTS
GISTs with delTyr were more frequently extragastric than those with delWK (69 vs 26%, P<0.0005). After curative surgery, median relapse-free survival were 10.8 and 11.1 months for patients with delTyr (n=14) and delWK (n=29), respectively (P=0.92). All patients treated with imatinib for a non-resectable or metastatic GIST had an objective response (n=15) or a stable disease (n=21) as best response, regardless of mutation. Median progression-free survival with imatinib were 21.9 and 18.9 months for patients with GIST with delTyr (n=14) and delWK (n=22), respectively (P=0.43).


CONCLUSIONS
In this large retrospective series, the type of KIT exon 11 mutation was correlated with the origin of GIST, but not with prognosis or response to imatinib.
Bachet
J-B
JB
EA4340 Epidémiologie et Oncogénesè des Tumeurs Digestives, Faculté de Médecine PIFO, UVSQ, Guyancourt, France.
Hostein
I
I
Le Cesne
A
A
Brahimi
S
S
Beauchet
A
A
Tabone-Eglinger
S
S
Subra
F
F
Bui
B
B
Duffaud
F
F
Terrier
P
P
Coindre
J-M
JM
Blay
J-Y
JY
Emile
J-F
JF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D018572:Disease-Free Survival; D005091:Exons; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D017353:Gene Deletion; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D011743:Pyrimidines / Q000627:therapeutic use; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D019009:Proto-Oncogene Proteins c-kit