CD8-positive memory T cells in tumor-draining lymph nodes of patients with breast cancer

Human immunological memory is a hallmark of the adaptive immune system and plays an important role in the development of effective immune responses against tumors. In the present study, we aimed to determine the frequencies of CD8 memory T cell subsets including T stem cell memory (TSCM) in tumor-draining lymph nodes of patients with breast cancer (BC). Mononuclear cells were obtained from axillary lymph nodes of 52 untreated patients with BC and stained for CD8, CCR7, CD45RO, CD95 markers to detect different subtypes of memory cells in the CD8 lymphocyte population. Data were acquired on four-color flow cytometer and analyzed with CellQuest Pro software. We observed that 47.65 ± 2.66% of CD8 lymphocytes expressed the CD45RO, a marker for memory T cells. Statistical analysis showed that the total frequency of central memory T cells (TCM) and their subset with low CD45RO expression was significantly higher in tumor-involved nodes compared to tumor-free ones (P = 0.024 and P = 0.017, respectively). The level of CD95 expression (based on mean fluorescence intensity) on the surface of TCM, their CD45RO and CD45RO subsets, and TSCM was higher in patients with stage II compared to those in stage I (P