PD-L1 expression in invasive solid papillary breast carcinomas

Indian J Pathol Microbiol. 2022 Apr-Jun;65(2):311-315. doi: 10.4103/IJPM.IJPM_1229_20.


Background: Invasive solid papillary carcinomas (ISPC) are rare malignant neoplasms in the classification of WHO 2019 breast tumors.

Aims: We aimed to investigate the correlations between programmed cell death ligand-1 (PD-L1) expression status of tumor and immune cells and clinicopathological parameters by molecular classification of this rare morphological subtype. This study will contribute to the literature about the PD-L1 expression state of ISPCs for the first time.

Material and methods: The study included 19 invasive solid papillary carcinoma cases diagnosed between 2009 and 2019 in Pathology Department. Molecular subtyping was performed in 19 cases by immunohistochemical studies (ER/PR, Her-2/neu, Ki-67), and PD-L1 expression was evaluated in neoplastic and immune cells.

Results: PD-L1 expression was detected in 4 (21%) cases, 3 (75%) of them were in luminal B and 1 (25%) were in the luminal A group. The correlation between molecular subtypes and PD-L1 expression was statistically significant (P = 0.016). Patients with PD-L1 expression had a higher Ki-67 index than patients without PD-L1 expression (P = 0.037). In addition, there was a statistically significant correlation between PD-L1 expressions of intratumoral lymphocytes and PD-L1 expressions of neoplastic cells (P = 0.004).

Conclusions: While predicting the group that will benefit more from immunotherapy in solid papillary carcinoma cases, not only PD-L1 expression of tumor cells but also PD-L1 expression in tumor infiltrating lymphocyte (TIL) can help. In addition, PD-L1 staining rates of tumor cells as well as clinicopathological parameters (molecular subtype, high Ki-67 index, presence of TIL) can be predictive about immunotherapy.

Keywords: Breast carcinoma; immunohistochemistry; programmed cell death ligand-1; solid papillary carcinoma.

MeSH terms

  • Adenocarcinoma, Papillary*
  • B7-H1 Antigen / genetics
  • Biomarkers, Tumor / metabolism
  • Breast Neoplasms* / pathology
  • Carcinoma, Ductal, Breast*
  • Carcinoma, Papillary*
  • Female
  • Humans
  • Ki-67 Antigen / genetics
  • Ki-67 Antigen / metabolism
  • Lymphocytes, Tumor-Infiltrating
  • Prognosis


  • B7-H1 Antigen
  • Biomarkers, Tumor
  • Ki-67 Antigen