Expression of programmed cell death-ligand 1 in invasive breast cancer and its clinical significance / 肿瘤研究与临床

ABSTRACT

Objective:To explore the expression of programmed cell death-ligand 1 (PD-L1) in invasive breast cancer and its relationship with clinicopathological characteristics.Methods:A total of 651 paraffin-embedded specimens of newly diagnosed invasive breast cancer patients including 98 cases of triple-negative breast cancer (TNBC) in the Affiliated Nanjing Drum Tower Hospital of Medical School of Nanjing University from January 2018 to August 2019 were collected. The immunohistochemical EnVision method was used to detect the expression of PD-L1 protein in tumor cells of breast invasive cancer and infiltrating lymphocytes. The expression rate of PD-L1 in tumor cells of cancer section tissues and tumor interstitial lymphocytes ≥1% was positive and < 1% was negative.Results:The positive expression rate of PD-L1 expression in breast invasive carcinoma was 47.0% (306/651), among which the positive expression rate of TNBC was 69.3% (68/98). PD-L1 had a high positive expression rate in patients with high World Health Organization (WHO) grade, large tumor size, vascular invasion, advanced pathological stage, negative estrogen receptor (ER) expression, negative progesterone receptor (PR) expression, positive p53, positive CK5/6, positive epidermal growth factor receptor (EGFR), and high Ki-67 value (all P < 0.05). In TNBC, PD-L1 had a high positive expression rate in patients with high WHO grade, invaded nerves, high Ki-67 value, positive CK5/6, and positive EGFR (all P < 0.05). Multivariate analysis showed that WHO grade ( HR = 1.511, 95% CI 1.139-2.003, P = 0.004), Ki-67 value ( HR = 1.847, 95% CI 1.259-2.709, P = 0.002), p53 expression ( HR = 2.083, 95% CI 1.487-2.916, P < 0.01), and EGFR expression ( HR = 3.490, 95% CI 2.002-6.086, P < 0.01) were independent influencing factors of PD-L1 expression. Conclusions:PD-L1 is highly expressed in invasive breast cancer, especially in TNBC. It could be used as a potential treatment target for patients with invasive breast cancer.