ABSTRACT
Alteration in peripheral blood lymphocytes [PBLs] is usually investigated to provide an evidence of the host immune responses to tumor antigens. The tumor infiltrating NK cells interact most closely with the tumor cells and more accurately reflect tumor host interactions. To analyze peripheral blood and tumor associated Natural Killer [NK] cells in patients with breast cancer by immunophenotyping. Twenty women suffering from breast cancer were examined; 12 of them were confirmed histologically to be invasive ductal carcinoma. PBL and tissue samples from patients and matched control group were processed for analysis by flow cytometry. Results of PBL analysis indicated a significant [P<0.05] increase in both the total number and activated NK cells in invasive ducal carcinoma patients compared to normal controls. No significant differences were noticed in the percent of NK cells and their activation marker expression in intra tumor lesion of the invasive ductal carcinoma and other tumors compared to benign lesions, however a decrease in the total NK number and activated NK cells was observed with progression of the tumor. Data of this investigation conclude that the total and activated NK cell number increase in peripheral blood of patients with breast cancer. The relationship between peripheral blood and intratumor NK cells needs more clarification, however, a decrease in intratumor NK cell number and their activation status occurs with tumor progression