Programmed death-ligand 1 (PD-L1) expression in tumour cell and tumour infiltrating lymphocytes of HER2-positive breast cancer and its prognostic value

• Published in: Scientific reports Vol. 7; no. 1; pp. 11671 - 10
• Main Authors: Kim, Ahrong, Lee, So Jeong, Kim, Young Keum, Park, Won Young, Park, Do Youn, Kim, Jee Yeon, Lee, Chang Hun, Gong, Gyungyub, Huh, Gi Yeong, Choi, Kyung Un
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 15.09.2017; Nature Publishing Group UK
• Subjects: Adult; Aged; Aged, 80 and over; Apoptosis; B7-H1 Antigen - analysis; Breast cancer; Breast Neoplasms - diagnosis; Breast Neoplasms - pathology; ErbB-2 protein; Female; Gene expression; Gene Expression Profiling; Humans; Immunohistochemistry; Immunotherapy; L1 protein; Lymphocytes; Lymphocytes, Tumor-Infiltrating - pathology; Microarray Analysis; Middle Aged; Paraffin; PD-1 protein; PD-L1 protein; Prognosis; Tumors; Young Adult
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-11905-7

Immunotherapy targeting PD-1/PD-L1 axis showed benefits in cancer. Prognostic significance of tumour infiltrating lymphocytes (TILs) has been determined. We evaluated PD-L1 protein expression in tumour cells and TILs, PD-L1 mRNA level and various histopathologic factors including TILs using 167 formalin-fixed paraffin embedded tissues and 39 fresh tissue of HER2-positive breast cancer. TILs level and PD-L1 expression in tumour cells and TILs were significantly correlated one another. PD-L1 positivity in tumour cells was associated with high histologic grade and high TILs level (p < 0.001, both). High PD-L1 immunoscore in TILs and high total immunoscore (in tumour cells and TILs) of PD-L1 were correlated with high histologic grade (p = 0.001 and p < 0.001, respectively), absence of lymphovascular invasion (p = 0.012 and p = 0.007, respectively), negative hormone receptor expression (p = 0.044 and p = 0.001, respectively) and high TILs level (p < 0.001, both). High PD-L1 mRNA expression was associated with high TILs level (p < 0.001, both). PD-L1 positivity in tumour cells was associated with better disease-free survival in HR-/HER2+ breast cancer (p = 0.039). PD-L1 expression in tumour cells and TILs are significantly associated with TILs level in HER2-positive breast cancer. PD-L1 expression in tumour cells might be positive prognostic factor in HR-/HER2+ breast cancers.