Expression and amplification of therapeutic target genes in retinoblastoma.
OBJECTIVE
We set out to evaluate alterations of the therapeutic target genes KIT (CD 117), EGFR, and HER-2 in human retinoblastoma.


METHODS
Ninety-five formalin-fixed, paraffin-embedded retinoblastomas were brought into a tissue microarray (TMA) format. Immunohistochemistry was performed to analyze the expression of CD117, EGFR, and HER-2. Fluorescence in situ hybridization (FISH) was utilized for detection of EGFR amplifications. Three tumors with strong CD117 positivity were sequenced for KIT exon 11 mutations.


RESULTS
Detectable CD117 expression was seen in 19% of all interpretable cases. Sequence analysis of the three tumors with the strongest CD117 expression revealed no mutations. EGFR was positive in 14% of all cases. No EGFR amplification was observed by FISH, however. All tumors were negative for HER-2 expression.


CONCLUSIONS
Our data suggest that selected cases of retinoblastoma may be candidates for anti-EGFR and imatinib mesylate (STI571) therapy.
Bösch
Doris
D
Universitäts-Augenklinik Basel, Mittlere Strasse 91, 4056, Basel, Switzerland.
Pache
Mona
M
Simon
Ronald
R
Schraml
Peter
P
Glatz
Katharina
K
Mirlacher
Martina
M
Flammer
Josef
J
Sauter
Guido
G
Meyer
Peter
P
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D005784:Gene Amplification / Q000502:physiology*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D018734:Genes, erbB-2 / Q000235:genetics*; D006801:Humans; D007124:Immunoenzyme Techniques; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics*; D019572:Retinal Neoplasms / Q000235:genetics*; D012175:Retinoblastoma / Q000235:genetics*
D066246:ErbB Receptors; D019009:Proto-Oncogene Proteins c-kit