Multiplexed immunofluorescence identifies high stromal CD68+PD-L1+ macrophages as a predictor of improved survival in triple negative breast cancer

Abstract

Triple negative breast cancer (TNBC) comprises 10–15% of all breast cancers and has a poor prognosis with a high risk of recurrence within 5 years. PD-L1 is an important biomarker for patient selection for immunotherapy but its cellular expression and co-localization within the tumour immune microenvironment and associated prognostic value is not well defined. We aimed to characterise the phenotypes of immune cells expressing PD-L1 and determine their association with overall survival (OS) and breast cancer-specific survival (BCSS). Using tissue microarrays from a retrospective cohort of TNBC patients from St George Hospital, Sydney (n = 244), multiplexed immunofluorescence (mIF) was used to assess staining for CD3, CD8, CD20, CD68, PD-1, PD-L1, FOXP3 and pan-cytokeratin on the Vectra Polaris™ platform and analysed using QuPath. Cox multivariate analyses showed high CD68+PD-L1+ stromal cell counts were associated with improved prognosis for OS (HR 0.56, 95% CI 0.33–0.95, p = 0.030) and BCSS (HR 0.47, 95% CI 0.25–0.88, p = 0.018) in the whole cohort and in patients receiving chemotherapy, improving incrementally upon the predictive value of PD-L1+ alone for BCSS. These data suggest that CD68+PD-L1+ status can provide clinically useful prognostic information to identify sub-groups of patients with good or poor prognosis and guide treatment decisions in TNBC.

GM-CSF derived from the inflammatory microenvironment potentially enhanced PD-L1 expression on tumor-associated macrophages in human breast cancer

“…In a representative PD-L1-positive breast cancer case, many Iba1 and PD-L1 double-positive cells were observed infiltrating the cancer stroma (Fig. 1A), and this observation was consistent with a previous report 18 . Lymphocyte-derived factors are well known to be stimulators that induce PD-L1 expression; however, no studies on the association between breast cancer-derived factors and PD-L1 expression on human macrophages have been published.…”

“…In breast cancer, recent studies have indicated that PD-L1 is mainly expressed on immune cells, especially on TAMs 18 . PD-L1 expression on cancer cells (cut-off value: 1%) and immune cells (cut-off value: 10%) were detected in 12% and 28% of breast cancer samples, respectively, and high PD-L1 expression in immune cells predicted a better clinical course 19 .…”

Case Report: Favorable Response and Manageable Toxicity to the Combination of Camrelizumab, Oxaliplatin, and Oral S-1 in a Patient With Advanced Epstein–Barr Virus-Associated Gastric Cancer

“…Compared with EBVnGC, the density of PD-L1+ tumor infiltrating immune cells was significantly greater in EBVaGC (10). Interestingly, several studies have shown that the quantity of PD-L1+CD68+macrophage may serve as an independent prognostic factor for survival or be significantly associated with favorable outcome to immunotherapy-based treatment in other malignancies, such as non-small-cell lung cancer, testicular lymphoma, and breast cancer (13)(14)(15). Hence, the quantity of PD-L1+CD68+macrophage may also serve as both an independent prognostic factor of EBVaGC and an effective predictor of EBVaGC in immunotherapy.…”

The Landscape of Tumor-Infiltrating Immune Cells in Feline Mammary Carcinoma: Pathological and Clinical Implications

“…Finally, in human breast cancer, the infiltration of immune cells, particularly in the most aggressive tumor subtypes (HER2-positive, triple negative basal-like and normal-like) has been associated with better outcome [ 49 ]. Indeed, recent studies in patients with triple negative tumors found that the presence of abundant sCD8 + T cells and sCD68 + macrophages are associated with good prognosis [ 50 , 51 ]. Accordingly, in this study, the data obtained showed that triple negative normal-like mammary carcinoma had high percentages of sCD3 + , sCD8 + and sCD68 + immune cells when comparing with other FMC subtypes.…”