Mammary carcinoma. Comparison of nuclear DNA content from in situ and infiltrative components.

Twenty-eight mammary carcinomas were analyzed with respect to their nuclear DNA content. Ten of the carcinomas were entirely in situ (noninfiltrative) while 18 showed areas of both infiltrative and noninfiltrative growth. The DNA content of individual tumor cells was measured in sections from the original paraffin-embedded specimens. In the tumors that had noninfiltrative as well as infiltrative zones, DNA analyses were performed in both areas. Comparison between the DNA patterns obtained from these different areas of the same tumor showed very close agreement. Both groups of tumors (those with and those without areas of invasion) contained some cases that showed a euploid DNA pattern and some cases that showed an aneuploid pattern. Furthermore, analysis of the DNA content of regional lymph node metastases in seven of the invasive cases did not show an increased aneuploidy in the metastases. The results suggest that, in mammary carcinomas, invasive and noninvasive tumors cannot be distinguished by DNA analysis and that tumor progression does not seem to be associated with a significant alteration of the nuclear DNA content.