DNA ploidy in intraductal breast carcinomas.

Cellular DNA-ploidy in 74 clinically detected intraductal breast carcinomas (IDCs) was analysed by flow cytometry. The histograms were classified as either diploid or aneuploid, and the DNA ploidy pattern compared with that of invasive breast carcinomas and normal breast tissue. All normal breast tissues were diploid while 28 (38%) of the IDCs were aneuploid, the DNA indices ranging from 1.32 to 2.00. The frequency of aneuploidy in invasive ductal carcinomas (73%) was significantly higher (P = 0.003), DNA index ranging from 1.34 to 2.92, compared with that in IDCs. Retrospectively, 14.5% of the patients had invasive breast cancer 16-166 months after the diagnosis of IDC. Neither DNA ploidy nor histopathological classification alone predicted clinical outcome, but patients with DNA diploid non-comedo IDC had a more favourable course.