Expression and distribution of programmed death receptor 1 and T cell immunoglobulin mucin 3 in breast cancer microenvironment and its relationship with clinicopathological features

Abstract

Objective: To explore the expression and distribution of programmed death receptor 1 (PD-1) and T-cell immunoglobulin mucin 3 (TIM-3) in breast cancer microenvironment and analyze the their correlation with the clinicopathological features. Methods: The specimens of tumor tissue and adjacent tissues from 30 patients with infiltrative breast cancer who were diagnosed as breast cancer from June 2016 to May 2017 in The First Hospital of Jiaxing were collected, and the specimen were divided into two parts along the center. After embedding and cryosectioning, the expression and distribution of PD-1 and TIM-3 protein in tumor tissues were observed by immunofluorescence staining. Another part of the specimen was cut and digested, and non-continuous density gradient centrifugation was used to extract tumor-infiltrating lymphocytes (TILs), real-time quantitative PCR (qRT-PCR) was used to detect the mRNA expression of PD-1 and TIM-3 in TILs. Meanwhile, the protein expression was determined by Western blotting. The relationship between the expression of PD-1 and TIM-3 and pathological parameters of breast cancer was analyzed with correlation analysis. Results: Immunofluorescence results showed that more PD-1 and TIM-3 positive cells were observed in the tumor tissues compared with the tumor-adjacent tissues. The qRT-PCR showed that the expression of PD-1 and TIM-3 mRNA in TILs were both significantly higher than those in paracancerous tissues (3.09±0.38 vs 1.26±0.23, 3.42±0.31 vs 1.57±0.29, t=4.16, 4.37, both P<0.05). At the protein level, the expression of PD-1 and TIM-3 in tumor tissue lymphocytes(0.66±0.08, 0.80±0.11) was significantly higher than those in cancerous tissues(0.10±0.01, 0.26±0.02) (t=6.79, 4.57, both P<0.05). There were significant differences in the expression of PD-1, TIM-3 mRNA in the TILs between the different tumor histological grades, tumor sizes, lymph node metastasis (t=2.22-2.99, all P<0.05). Correlation analysis showed that there was a significant positive correlation between the expression of PD-1 and TIM-3 in tumor tissues (r=0.616, P<0.01). Conclusions: In the breast cancer microenvironment, PD-1, TIM-3-mediated signaling pathway plays an important role in the occurrence and development of breast cancer, it provides a new basis for the combination therapy of breast cancer.