The Expression of PD-L1, CD47, CD4, and CD8 in Breast Cancer before and after Neoadjuvant Chemotherapy and Their Relationship with Clinicopathological Features and Prognosis
Authors: He Chenyu , Zhu Mingzhi , Huang Huifen , Chen Dong , Ren Huayan , Li Wencai , Gao Dongling , Gu Yuanting 
Published: April 2022

Abstract
Purpose: Several studies discussed different chemotherapy drugs that have influenced the expression of PD-L1 and CD47 in vitro and in vivo experiments. However, in breast cancer, neoadjuvant chemotherapy (NAC) influence on the changes of PD-L1 and CD47 trends is still controversial. In this study, we retrospectively investigated the effects of NAC on the expression of PD-L1, CD47, and tumor infiltrating lymphocytes (TILs) in breast cancer. The correlation between different immune indicators. As well as its relationship with clinicopathological features and prognosis. Methods: A total of 77 patients with invasive breast cancer who underwent NAC between May 2016 to July 2017 were included. Immunohistochemistry was used to detect the expression of PD-L1, CD47, CD4, and CD8 in breast biopsy tissues before NAC and tumor resected tissues after NAC. Paired Chi-square test was used to analyze the changes of PD-L1, CD47, CD4, and CD8 before and after NAC. The relationship between the expression of PD-L1 and CD47 before NAC and clinicopathological features of patients was evaluated by the Chi-square test. Spearman correlation analysis was used to discuss the correlations in the four indicators and their correlations with chemotherapy efficacy. Disease-free survival (DFS) and overall survival (OS) were compared in each immune indicator before and after NAC. Results: (1) Among 77 patients, a total of 16 cases showed pathological complete response (pCR) after NAC, in which the expression of PD-L1 and CD47 was not counted in the paired Chi-square according to the judgment standard. CD47expression after NAC was lower than before NAC in 61 patients (23.0% vs 55.7%, P <0.001). CD4 expression after NAC also lower than before in 77 patients (63.6% vs 94.8%, P <0.001). There is no significant different in PD-L1 and CD8 expression (34.4% vs 31.1%; 97.4% vs 94.8%, P >0.05).(2) Before NAC, CD47 expression was correlated with age ( P =0.048) and histological grade ( P =0.015) in breast cancer tissues of the 77 patients. CD47 expression was not associated with ER, PR, Ki-67, HER-2, tumor diameter, grade, lymph node metastasis, molecular subtypes, and pTNM stage ( P >0.05). PD-L1 expression was not correlated with the above clinicopathological features ( P >0.05). (3) CD47 expression was correlated with PD-L1 before NAC( P <0.001). Other indicators do not correlate with each other( P >0.05). (4) The expression of CD4+T cells and CD8+T cells were positively correlated with non-pCR after NAC ( P =0.002, P =0.005). Other factors showed no relation with therapy efficacy( P >0.05). Before NAC, CD8+T cells expression was associated with DFS ( P =0.0365), while the expression of other factors was not associated with overall survival or DFS ( P > 0.05). Conclusion: NAC could influence the tumor immune microenvironment, such as the expression of CD47 and CD4, but have no effect on PD-L1 and CD8, which suggests that it is better to retest the immune indicators after chemotherapy to prevent negative patients could not benefit from immune therapy. CD47 expression was related to the patient’s age and histological grade before NAC. Innate immune response and adaptive immune response both participate in tumor immune escape procedures in breast cancer. After NAC, CD4+ T cells and CD8+ T cells tend to express more in the tumor. And patients with higher expression of CD8+ T cells are likely to have longer DFS.