Comparative study of interphase cytogenetics, flow cytometric analysis, and nuclear grade of fine-needle aspirates of breast carcinoma.

The correlation between DNA ploidy and S-phase fraction (SPF) by flow cytometry (FCM) and the detection of numerical chromosomal abnormalities (NCA) by interphase cytogenetics (IC) involving chromosomes 8 and 12 was studied in 20 human breast lesions (17 breast carcinomas, 2 fibroadenomas, and 1 sclerosing adenosis). Initial diagnosis was performed on fine-needle aspiration biopsy (FNAB) material with subsequent histologic confirmation. FCM was performed on formalin-fixed paraffin-embedded tissue while IC by fluorescence in situ hybridization (FISH) was done on alcohol fixed FNAB materials. Sixteen (80%) cases showed concordance between FCM and IC with respect to the presence or absence of aneuploidy. The remainder of the cases (20%), which were all malignant neoplasms, showed discrepancies between the two methods, all four were DNA-diploid with low SPF by FCM but showed various NCA by IC. Nuclear grades (NG) of all the malignant samples were also evaluated and correlated with both FCM and IC studies. Although a good correlation was observed between NG and FCM, a better correlation was seen between NG and IC. This study shows that although IC by FISH correlated well with FCM analysis, it can detect NCA in DNA-diploid, low SPF tumors. It also correlates well with the NG of the tumor. The increased sensitivity provided by IC in detecting aneuploidy may be of great prognostic significance in low stage, DNA-diploid, low SPF breast carcinomas.