Gene amplification and overexpression of HER2 in renal cell carcinoma.

Abstract

To determine the frequency of HER2 genetic abnormalities in renal cell carcinoma (RCC) and hence assess the potential suitability of Herceptin immunotherapy. Tumours from 27 patients with RCC were assessed; all patients had undergone nephrectomy. Benign renal tissue from the nephrectomy specimens was studied in seven patients. Gene amplification was assessed using fluorescent in-situ hybridization, and protein over-expression using immunohistochemistry. Twenty-four patients had clear cell renal carcinoma, two had papillary renal carcinoma and one a sarcomatoid variant carcinoma. There was no HER2 amplification in the tumours or the benign renal tissue. Polysomy 17 was detected in 11 of 27 tumours (41%) and increased HER2 copy number in seven (26%). Both polysomy 17 and increased HER2 copy number were absent in the benign renal tissue. Three tumours (11%) and six of the seven benign renal tissue samples over-expressed the HER2 protein. HER2 amplification is absent and protein over-expression uncommon in RCC. This casts doubt on the suitability of Herceptin in the treatment of RCC.