The reliability of microspectrophotometric and flow cytometric nuclear DNA measurements in adenocarcinomas of the breast.

The reliability of microspectrophotometric (MSP) and flow cytometric (FCM) nuclear DNA measurements has been studied in 50 human breast adenocarcinomas. The tumor material was obtained by means of fine-needle aspiration biopsy, and all samples except one were found to be highly representative. The results confirm earlier observations that a good correlation exists between modal value (MV) determined by MSP and DNA index (DI) determined by FCM. However, when tumors were classified into low and high malignant variants according to FCM/DI, FCM/S-phase percentages, and MSP histogram types, the concordance was less pronounced. This was found to be due mainly to the fact that in near-diploid tumors a discrepancy exists between MSP and FCM ploidy, as well as between MSP distribution pattern and the estimated percentages of cells in the S-phase region. Another source of discrepancy was observed in tumors with stemlines in the normal tetraploid region, including cells with highly scattered aneuploid DNA values. These tumors were judged by MSP as aneuploid/high malignant and by FCM as euploid/low malignant. In view of this discrepancy, we conclude that the simple determination of the stemline position by MSP/MV or FCM/DI is not sufficient for adequate cytochemical malignancy grading of breast carcinomas. We suggest that a combination of ploidy and percentage of cells scattered outside the modal peaks is a more sensitive method for optimal cytochemical malignancy grading in breast carcinomas.

Cytophotometrical and biochemical characterization of nonpalpable, mammographically detected mammary adenocarcinomas.

Fifty nonpalpable, mammographically detected, invasive breast carcinomas were analysed with respect to DNA distribution pattern, steroid receptor content, and histopathological criteria. No significant histomorphological differences were found as compared to palpable breast carcinomas. In contrast, DNA distributions of palpable and nonpalpable tumors differed. Ninety percent of these relatively small breast carcinomas were found to exhibit nuclear DNA amounts within the diploid and tetraploid regions of normal breast epithelium. In earlier findings in palpable breast carcinomas, 55% are of the diploid-tetraploid type. The mean cellular content of the estrogen receptor was 1.0 fmole/microgram DNA in this group of mammographically detected carcinomas, which is significantly higher than in routinely detected, ie, larger, breast carcinomas. It is suggested that, despite the histomorphological findings, nonpalpable, mammographically detected breast carcinomas are dominated by biologically highly differentiated, slowly proliferating carcinomas with a favourable prognosis.