Ploidy Analysis by In Situ Hybridization of Interphase Cell Nuclei in Fine-Needle Aspirates From Breast Carcinomas: Correlation With Cytologic Grading

Fine-needle aspirates from 54 breast cancer patients were investigated for numeric aberrations in chromosomes 6, 7, 12, and 17 by in situ hybridization (ISH) of interphase cell nuclei. Ploidy findings were compared with cytologic grading of tumors. Aneuploidy was found in 73% of cases. Chromosomes 6 and 7 showed numeric abnormalities in 63% and 62% of cases, respectively, whereas chromosome 17 retained a disome pattern in 2/3 of the tumors. Thirteen cancers (28% of 47 with four analyzed probes) had a normal signal number in all four chromosomes. In 17 (36%), all four had signal gain. Another 17 showed a mixed disome/aneusome pattern. They presented a continuum of increasing numeric abnormalities, 82% disomy for chromosome 17, and 13 of them were grade 2, indicating intermediate biologic properties. Correlation between grading and ploidy was good, with 10 of 11 grade 1 carcinomas showing diploidy, whereas 33 of 36 grade 2 and 3 tumors had numeric aberrations.