Retrospective evaluation of c-erbB-2 oncogene amplification using competitive PCR in collecting duct carcinoma of the kidney.

PURPOSE: To evaluate retrospectively c-erbB-2 oncogene amplification in paraffin embedded specimens of collecting duct carcinoma of the kidney (CDC) with competitive polymerase chain reaction (PCR). MATERIALS AND METHODS: Eleven CDC specimens were evaluated with a novel PCR procedure for oncogene amplification measurement, which provides sensitive and accurate results even in presence of low-quality DNA, unsuitable for Southern blot techniques. RESULTS: c-erbB-2 oncogene amplification was present in 5 out of 11 cases (45%) with a number of copies ranging from 4 to 12. All patients presenting oncogene amplification decreased within one year, while 50% (3/6) of those without amplification are alive with a mean follow-up of 42 months. CONCLUSIONS: The high incidence of c-erbB-2 oncogene amplification in CDC further characterizes this tumor as a separate entity from renal cell carcinoma, and shows some genetic characteristics in common with transitional cell carcinoma.