Flow cytometry of breast carcinoma. III. Possible altered kinetics in axillary lymph node metastases.

The cell cycle distribution of human mammary carcinoma was determined by flow cytometry in 21 cases and compared with that of the same tumor concurrently metastatic in regional lymph nodes. The percentage of S-phase cells in the nodal metastasis as compared to the primary tumor was significantly lower in estrogen-binding-positive tumors than in estrogen-binding-negative tumors. Since we do not have evidence of clonal evolution in the metastases, it is possible that there is a local inhibitory effect of the lymph node on tumor cell proliferation in the case of some estrogen-binding-positive tumors.