Correlation of cytologic findings and chromosomal instability detected by fluorescence in situ hybridization in breast fine-needle aspiration specimens from women at high risk for breast cancer

Cytologic evaluation of ductal lavage or random periareolar fine-needle aspiration (FNA) specimens has been proposed to improve risk stratification of women at high risk for breast cancer. However, cytologic assessment of morphologic changes is subjective. To assess the utility of fluorescence in situ hybridization (FISH) in the categorization of breast lesions, we prospectively evaluated 32 random periareolar FNA specimens from 27 women at high risk for breast cancer. Cytologic specimens were prepared using the thin preparation technique, and diagnoses were made on the basis of previously published criteria. Specimens were also evaluated by FISH for chromosomes 1, 8, 11, and 17. Monosomy was defined as the loss of one signal or both signals in >20% of cells, and polysomy was defined as the presence of ≥3 signals in >6% of cells. Cytologic smears from seven invasive ductal carcinomas and nine benign breast specimens from women at low risk for breast cancer were included for comparison. In the high-risk group, cytologic findings were nonproliferative epithelium (NPE) in 16 cases and hyperplasia in 16 cases. Chromosomal aberrations were detected in 11 (69%) of 16 NPE cases, 14 (89%) of 16 hyperplasia cases, seven (100%) of seven carcinoma cases, and none of the low-risk cases. High-risk cases had significantly more monosomy of chromosomes 1, 11, and 17 and polysomy of chromosome 8 compared to low-risk cases and significantly less polysomy of chromosomes 1, 8, 11, and 17 compared to patients with cancer. There were no significant differences in monosomy or polysomy of individual chromosomes or a combination of chromosomes between the NPE and hyperplasia groups. This study shows that aberrations of chromosome number are common in high-risk women irrespective of cytologic findings. Studies evaluating the association between specific patterns of chromosomal polysomy and progression to malignancy may be warranted.