EGF-r gene copy number changes in renal cell carcinoma detected by fluorescence in situ hybridization.
Expression of epidermal growth factor receptor (EGF-r) is a frequent event in renal cell carcinoma (RCC). To investigate the role of EGF-r gene copy number changes related to EGF-r overexpression, 50 RCC specimens were examined by fluorescence in situ hybridization (FISH) and immunohistochemistry. Dual-labelling FISH with a repetitive pericentromeric probe for chromosome 7 and a probe for the EGF-r gene (at 7p13) was performed to analyse the EGF-r copy number in relation to chromosome 7 copy number on a cell-by-cell basis. Polysomy 7 was frequent in all histological types of RCC. Chromosome 7 polysomy was found in 26 of 35 clear cell (74 per cent), nine of nine papillary, and three of three chromophobe RCCs. EGF-r gene copy number was closely associated with the chromosome 7 copy number on a cell-by-cell basis. No EGF-r gene amplifications were found. EGF-r positivity was found in 37 of 50 cases (74 per cent) by immunohistochemistry. EGF-r positivity was more common in clear cell (81 per cent) than in papillary tumours (40 per cent; P = 0.029). Neither chromosome 7 nor EGF-r gene copy number was associated with EGF-r expression, indicating that an increased gene dosage is not a mechanism of EGF-r overexpression in RCC.
Institute of Pathology, University of Basel, Switzerland.
H
H
Moch
G
G
Sauter
T C
TC
Gasser
L
L
Bubendorf
J
J
Richter
J C
JC
Presti
F M
FM
Waldman
M J
MJ
Mihatsch
D002292:Carcinoma, Renal Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002897:Chromosomes, Human, Pair 7; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D018628:Gene Dosage; D015870:Gene Expression; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D019394:Ki-67 Antigen / Q000378:metabolism; D007680:Kidney Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism
D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D066246:ErbB Receptors