FLOW CYTOMETRIC DNA ANALYSIS OF BREAST CANCERS WITH PREDOMINANCE OF CARCINOMA IN-SITU - A COMPARISON OF THE PREMALIGNANT AND MALIGNANT COMPONENTS

Flow cytometric DNA analysis was performed on unfixed frozen tissue sa mples from 48 cases of invasive breast cancer (IC) with a predominance of ductal carcinoma in situ (DCIS), In 15 cases the samples contained only the DCIS component, in 17 cases only the IC component, whereas i n 16 cases separate samples from the DCIS as well as the IC part withi n the individual lesion were available, In the latter 16 cases, comple te or partial accordance in DNA ploidy between DCIS and IC was found i n 12 cases,,whereas no correspondence could be demonstrated in the rem aining 4 cases, possibly due to intratumoral DNA heterogeneity, Compar ison of the DNA index distribution in samples of DCIS and IC from the 48 cases showed concordant results except for the DNA hyperdiploid sub class, in which 6 clones were found in the DCIS portion compared to 18 clones in the IC portion, S-phase fractions were also comparable in t he two groups, A comparison of the DCIS component from the present ser ies of breast cancers to our previous series of pure DCIS also showed similar results with respect to the DNA index distribution, DNA hetero geneity, and S-phase fraction, No differences could be demonstrated be tween DCIS with and without invasion, The results indicate that the DN A ploidy pattern of breast cancer, as detected by flow cytometric DNA analysis, is established at the preinvasive stage of carcinogenesis.