Fluorescence in situ hybridization analysis of renal oncocytoma reveals frequent loss of chromosomes Y and 1

Purpose: Cytogenetic studies of a small number of renal oncocytomas have indicated that loss of chromosomes 1 and Y may be involved in the pathogenesis of this tumor. To evaluate these observations further we selected paraffin embedded renal oncocytoma specimens from 20 male and 10 female patients for fluorescence in situ hybridization analysis. Materials and Methods: Isolated nuclei were prepared from paraffin embedded specimens, and fluorescence in situ hybridization was performed with enumeration probes for chromosomes 1, 12, X and Y. Results: Tumors from 10 male (50%) and 4 female (40%) patients demonstrated chromosomal alterations. Loss of chromosome Y was observed in specimens from all 10 male patients, and loss of chromosome 1 or gain of chromosome 12 was noted in 5 and 2 of these specimens, respectively. Of the 4 female patients with chromosomal abnormalities 2 had loss of chromosome 1, 1 had gain of chromosome 1 and 1 had gain of chromosome 12. Conclusions: Our results confirm that loss of chromosomes Y and 1 is common in renal oncocytoma, and that the alterations are probably involved in the pathogenesis of this tumor.