Expression of PD-1/PD-L1 in primary breast tumours and metastatic axillary lymph nodes and its correlation with clinicopathological parameters

Chenxi Yuan,Jinming Yu,Qian Yu,Xinzhao Wang,Zhaoyun Liu,Zhiyong Yu,Mengxue Bian

doi:10.1038/s41598-019-50898-3

Abstract

The aim of this study was to compare the expression of PD-1/PD-L1 in primary breast tumours to that in metastatic axillary lymph nodes and to determine the correlation between the PD-1/PD-L1 status and clinicopathologic characteristics. In total, 47 paired breast tumour and metastatic axillary lymph node samples were collected in this study. Immunohistochemical technology was used to determine the positivity or negativity of PD-1/PD-L1. Other patient information was retrieved from medical records. Significant differences in PD-L1 expression were observed between primary breast tumours and paired axillary lymph nodes. We also observed that the presence of PD-1/PD-L1 positivity in metastatic lymph nodes was significantly associated with poor prognostic features, such as a high Ki-67 index (p = 0.048), a high TNM stage (p = 0.012), a large number of metastatic lymph nodes (p = 0.002), and a high histology grade (p = 0.029). Since heterogeneity exists, it is necessary to determine the PD-L1 status in both the primary tumour and metastatic lymph nodes.

Highlights

Breast cancer has a high incidence and mortality rate and is estimated to be the most common malignancy in females worldwide[1]
When the molecular phenotypes were taken into account, 10 patients each (21%) were diagnosed with the Luminal A subtype and the HER2 overexpressing subtype, 23 patients (49%) were diagnosed with the Luminal B subtype, and 4 patients (9%) were diagnosed with the triple-negative breast cancer (TNBC) subtype
In 2013, immunotherapy applied in the field of cancer treatment was selected as “the year’s breakthrough” by the editors of Science due to its ability to harness the immune system to battle tumours, marking a turning point in the history of cancer therapy[14]

Summary

Introduction

Breast cancer has a high incidence and mortality rate and is estimated to be the most common malignancy in females worldwide[1]. As a complex and highly heterogeneous disease, breast cancer can be classified into different subtypes based on its molecular features[2]. This categorization has great significance in guiding cancer treatment: hormone receptor-positive patients can benefit from endocrine therapy, while targeted therapy has been extensively utilized in human epidermal growth factor receptor-2-overexpressing (HER2+) patients. Www.nature.com/scientificreports antigen-presenting cells (APCs), such as B lymphocytes, macrophages, and tumour cells[7]. In view of the significance of the PD-1/PD-L1 axis in the immune environment of cancer[13], our study aimed to investigate PD-1/PD-L1 expression in both primary breast tumour tissue and ipsilateral axillary lymph node metastases. We elucidated the association between the PD-1/PD-L1 status and clinicopathological characteristics in breast cancer patients

Objectives

Methods

Results

Conclusion