Chromosome-specific aneusomy in carcinoma of the breast

Fluorescence in situ hybridization was performed on touch preparations from 55 primary infiltrating ductal carcinomas of the breast to determine numeric chromosome abnormalities. The frequency of aneusomy, measured by both nondisomy and chromosomal gain, was determined for chromosomes X, 4, 6-12, 17, and 18 with the use of chromosome-specific, α-satellite DNA probes. The presence of chromosome-specific numeric abnormalities was correlated with established clinicopathological parameters, including tumor size, lymph node involvement, tumor grade, estrogen receptor level, and menopause status. In addition, a case-control study was performed to explore a possible association between chromosome-specific aneusomy and recurrence in lymph-node-negative patients. Although chromosomes 8 and 6 were most frequently aneusomic, numeric abnormalities of chromosomes 4 and 11 were most strongly associated with established prognostic factors. For chromosomes 4 and 11, strong associations were found with tumor involvement of lymph nodes and increased tumor size, along with a weaker association with tumor grade. In addition, numeric abnormalities of the following chromosomes were associated with the corresponding prognostic factors: chromosomes X, 7, and 12 with lymph node status; chromosomes 10, 17, and 6 with tumor size; and chromosomes 7, 12, 17, and X with tumor grade. No correlations were observed with estrogen receptor level or menopause status. In the case-control study performed on isolated nuclei of paraffin-embedded tissue from lymph node-negative breast cancer patients (19 cases and 19 controls), the gain of chromosome 4 was correlated with disease progression. These findings suggest that chromosome-specific aneusomy is associated with certain established prognostic factors and may be associated with disease progression.