The Relationship of CD8-Positive Cytotoxic T Lymphocytes and other Clinicopathologic Features with Survival in Breast Cancer

CD8-positive T lymphocytes are important part of cell-mediated immunity and play a central role in induction of immune response against tumor progression. So, these cells might have potential to be used in clinic along with other prognostic biomarkers; however no definite comparison on validation of this maker has been conducted. The purpose of this study was to assess the role of CD8-positive cells in breast cancer outcome and to compare the correlation of tumor-infiltrating CD8-positive cytotoxic lymphocyte density and clinicopathologic parameters with mortality and survival rates in breast cancer.
CD8-positive T cells were detected via immunohistochemistry using the paraffin-embedded tumor samples of 52 patients with breast cancer. Clinicopathologic data including tumor type and grade, lymph node involvement, stage, lymphovascular invasion, metastasis, relapse, patient's family history, and estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki67 markers were reviewed. Mortality and survival rates were obtained.
Findings: There were no statically significant correlations between presence of CD8 and mortality (P = 0.05) or survival (P = 0.09). Increased mortality rate was significantly associated with increased Ki67 (P = 0.045), lymph node metastasis (P = 0.020), higher stage (P = 0.020), metastasis (P > 0.001), and relapse (P = 0.008). In addition, overall survival was significantly associated with lymph node involvement (P = 0.003), higher stage (P = 0.009), metastasis (P = 0.020), negative PR (P = 0.020), and negative Ki67 (P = 0.010).
Although some previous studies reported CD8 as a prognostic marker to be complementary of tumor, node, and metastasis (TNM) staging, but our data did not show any correlation between the presence of CD8 with mortality or survival. The role of immunologic reaction in tumor microenvironment should be further validated using larger patient population with analysis of multiple immune cell lines together.