Near haploidy in breast cancer: a particular pathway of chromosome evolution.

In a series of 260 cytologically abnormal breast cancers studied in our laboratory, we observed a single case of near-haploid karyotype: 27,X, +der(1;16)(q10;p10), +7, +14, +15. A review of published cases of near-haploid malignancies suggests that near haploidy belongs to a process of chromosome evolution distinct from that of most epithelial cancers in which hypodiploidy is strongly associated with the occurrence of unbalanced structural rearrangements. In near-haploid tumors, chromosome loss is independent from chromosome rearrangements and may not be associated with an adverse prognosis.