Renal oncocytomas with rearrangements involving 11q13 contain breakpoints near CCND1

Oncocytomas are typically benign epithelial tumors whose predominant feature is a massive accumulation of mitochondria in the cytoplasm. With the goal of identifying genes controlling mitochondrial proliferation, we studied three oncocytomas belonging to the cytogenetic subgroup with 11q13 rearrangements. Fluorescence in situ hybridization using bacterial artificial chromosome (BAC) clones showed that the 11q13 breakpoints in all three tumors were near the CCND1 (previously BCL1) gene and did not disrupt any other known gene. The rearrangement in one tumor consisted of a segmental duplication that included 11q13, suggesting that known mitochondrially targeted genes immediately distal to CCND1 may be involved in oncocytic proliferation.