Recurring breakpoints of 1p13 approximately p22 in osteochondroma.

Cytogenetic studies of osteochondromas are scarce but have previously shown recurring clonal aberrations involving chromosome 8. We have studied a series of eight tumors and have found recurring aberrations not only involving chromosome 8, but also chromosome 1 in five of the seven abnormal tumors. Surprisingly, three of the chromosome 1 aberrations involved pericentric inversions. Four tumors showed aberrations involving the region 1p13 approximately p22 by mechanisms including inversion, insertion, and translocation. These findings indicate that aberrations of chromosome 1p, in a region spanning 1p13 approximately p22, may be nonrandomly involved in the cytogenetic progression of osteochondroma.