c-Kit expression and mutations in phyllodes tumors of the breast.
BACKGROUND
Phyllodes tumors (PTs) represent uncommon fibroepithelial lesions of the breast that express c-Kit and platelet-derived growth factor receptor-alpha, similar to gastrointestinal stromal tumors (GISTs). 'Activating' mutations in these genes underlie responsiveness of GISTs to imatinib. Standard treatment for breast PTs is wide local excision, with no role for targeted therapies.


METHODS
c-Kit (CD117) expression was investigated by immunohistochemistry in 17 cases of breast PTs. Fourteen of these cases were also subjected to KIT mutation analysis by dideoxynucleotide sequencing.


RESULTS
Five out of 17 (29%) tumors showed weak stromal staining for CD117. No previously described 'activating' mutations were found in exons 9, 11, 13, or 17 of the KIT gene. A silent germline point mutation was found in exon 17 of one case.


CONCLUSIONS
These data do not suggest a pathogenetic role for KIT in breast PTs. Inhibition of c-Kit signaling is unlikely to be helpful in this condition.
Department of Medicine, Section of Hematology-Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126, USA. pbose@mcvh-vcu.edu
Prithviraj
P
Bose
S Terence
ST
Dunn
Jian
J
Yang
Richard
R
Allen
Christian
C
El-Khoury
Arafat
A
Tfayli
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D009367:Neoplasm Staging; D003557:Phyllodes Tumor / Q000235:genetics* / Q000473:pathology; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism; D015996:Survival Rate
D014408:Biomarkers, Tumor; D019009:Proto-Oncogene Proteins c-kit