Prognostic importance of PD-L1, PTEN, PHH3 and Ki-67 expressions in invasive breast carcinomas

Introduction: Breast cancer is the most common cancer in women. Prognostic factors gain importance in determining the prognosis in breast cancer and preventing local recurrence and mortality. Where traditional prognostic factors are insufficient, new markers are needed to identify high-risk patients and guide treatment decisions. The aim of this study was to investigate the relationship between PD-L1, PTEN, PHH3 and Ki-67 immunohistochemical stain expressions with prognostic clinicopathological parameters in breast cancer. Materials and methods: In this study, lumpectomy and mastectomy materials of 85 patients who were treated and operated in Bolu Abant Izzet Baysal University Izzet Baysal Training and Research Hospital between 2014-2019 were evaluated retrospectively. Clinical information about the patients was obtained from the hospital information system. Pathological prognostic parameters were reevaluated on slides of surgical resection materials. As a result of immunohistochemical staining applied to 4 micron thick sections from formalinfixed, paraffin-embedded blocks, PD-L1 expression in tumor immunology and PTEN, PHH3 and Ki-67 expressions that have roles in the cell cycle were examined. Immunohistochemical staining results were compared with clinicopathological parameters proven to be related to prognosis. Descriptive statistics are given with frequency, percentage, average, and standard deviation values. To examine whether the prognostic factor measurements in the study are different according to PD-L1, PHH3, Ki-67 and PTEN positivity, Mann Whitney U test analysis was performed. In the study, p <0.05 was considered significant. The analyzes were made with the SPSS 25.0 program. Results: In the study, the mean age of 85 invasive breast carcinoma cases was 58.33 ± 12.50, 82 (96.4%) were female and 3 (3.6%) were male. PD-L1 positivity was observed in 21 (24%) of the patients, PTEN loss (H-score <90) in 42 (49.4%) cases, and PHH3 positivity in 36 (42.3%) cases. While Ki-67 expression was below 20% in 57 cases (67%), it was above 20% in 28 cases (33%). A statistically significant relationship was found between PD-L1 and large tumor size, high histological grade, multifocality, lymphovascular invasion, Ki-67 expression and estrogen and progesterone receptor negativity. A statistically significant relationship was found between PTEN loss and large tumor size, high histological grade, estrogen and progesterone receptor negativity. A statistically significant relationship was found between PHH3 and advanced age, large tumor size, high histological grade, multifocality, Ki-67 expression, estrogen and progesterone receptor negativity. A statistically significant relationship was found between Ki-67 and large tumor size, high histological grade, lymphovascular invasion, estrogen and progesterone receptor negativity. Conclusion: While PD-L1, PHH3 and Ki-67 expression was associated with poor prognostic parameters in breast carcinomas, a negative correlation was found with loss of PTEN. It is thought that the evaluation of PD-L1, PTEN, PHH3 and Ki-67 expressions can be a potential biomarker that can be used in predicting the prognosis of breast cancer, can contribute to the development of appropriate immunotherapy agents by understanding the immunological bases of the tumor, and may guide the development of targeted therapies.