Flow cytometric analysis of DNA ploidy in primary, metastatic and recurrent breast cancers

Although there have been many studies analyzing the heterogeneity of DNA ploidy either in primary breast cancer or between the primary and synchronous metastatic lesions of breast cancer, few studies have been made regarding a comparison of DNA ploidy between the primary and recurrent lesions of breast cancer. Flow cytometric analyses for DNA ploidy were performed on both the primary lesions and the matching synchronous metastatic lymph nodes of 104 breast cancers and on both the primary and matching recurrent lesions of 31 breast cancers. A concordance of DNA ploidy between the primary lesions and the matching metastatic lymph nodes was found in 80 (77%) cases, while a concordance of DNA ploidy between the primary and matching recurrent lesions was found in 22 (71%) cases. Forty-six (94%) of 49 cases showed less than an 8.0% difference in the DNA indices of the aneuploid peaks between the primary lesions and the metastatic lymph nodes, while 13 (87%) of 15 cases showed less than 15.0% difference in the DNA indices between the primary and recurrent lesions. The aneuploid group and the heterogeneity group, divided according to the comparison of DNA ploidy between the primary and synchronous metastatic lesions, had a worse disease-free survival than that of the diploid group (p=0.0426 and p=0.0503, respectively). In conclusion, the majority of DNA ploidies are consistent among the primary, synchronous metastatic and recurrent lesions of breast cancer. The existence of aneuploidy itself may also play a prognostic role in breast cancer.