CD68, CD86 and CD163 Expression Profile in Breast Cancer Molecular Subtypes

Abstract

Background and aimBreast cancer (BC) is the second most common global cause of cancer deaths among women. Several immune cells are identified in the tumor microenvironment of BC patients, including tumor‐associated macrophages. We aimed at exploring the expression of distinct functional phenotypes using macrophages’ markers, where CD68 is a pan‐macrophage marker, CD86 is a marker expressed in polarized M1 subtype, and CD163 is expressed in M2 polarized subtype.MethodsA retrospective study was performed using 90 formalin‐fixed paraffin‐embedded BC specimens for the immunohistochemical analysis of CD68, CD86 and CD163. Also, an in silico tool, UALCAN, was used on a larger cohort (n=1,081) of BC patients to investigate the expression of these markers. The macrophages’ markers were then associated with the clinicopathological parameters of BC patients. Triple‐negative BC cell line “CAL‐51” and luminal BC cell line “MCF‐7” were used to collect their respective supernatants that were added to THP‐1 derived macrophages. Then CD86 and CD163 were assessed using western blot.ResultsThe pan‐marker of macrophages, CD68, along with the M1 CD86 marker and M2 CD163 marker, showed positive results in all the 90 investigated patients (Figure 1). CD86 expression was significantly associated with body mass index (BMI) and Ki‐67 proliferation marker. On the other hand, CD163 was significantly correlated with tumor size, estrogen, progesterone receptors, and BC molecular subtypes. Moreover, the high expression of CD86 and CD163 showed unfavorable outcome and survival of BC patients. In silicoanalysis revealed a significant increase in the CD86 expression in BC patients, especially in the triple‐negative subtype. Similarly, CD163 expression was found to be higher in the triple‐negative subgroup compared to the luminal group (Figure 2A). Additionally, in vitro work showed that the macrophages induced from the monocytic THP‐1 cell line express high levels of CD163 upon the exposure to conditioned media collected from the luminal BC cell line “MCF‐7”, thus showing M2 phenotype. On the contrary, CD163 expression was reduced upon the exposure to the conditioned media collected from the triple‐negative BC cell line “CAL51”, indicating more M1 phenotype (Figure 2B).ConclusionTumor‐associated macrophages are associated with cancer progression and molecular subtypes. Hence, identifying the macrophages polarization profiles in each molecular subtype might aid their use as potential therapeutic targets.