CD155 Expression in Invasive Breast Carcinoma: Association with Immune Tumor Microenvironment.

BACKGROUND &

OBJECTIVE

CD155 is as an immune checkpoint molecule that interacts with various activating and inhibitory receptors on T- lymphocytes and natural killer (NK) cells in tumor microenvironment (TME). NK cells and tumor associated macrophages (TAMs) are major components of the immune TME.

METHODS

85 cases of invasive breast carcinoma (IBC) were evaluated for immunohistochemical expression of CD155, CD56, and CD163.

RESULTS

CD155 was positive in 52.9% of cases, and was significantly associated with larger sized, higher grade, advanced stage tumors, positive lymphovascular invasion (LVI), and aggressive molecular subtypes of IBC. High density of CD56 stained tumor infiltrating NK cells was detected in 30.6% of cases, which was significantly related to larger sized, higher-grade tumors, and aggressive molecular subtypes. High density of stromal TAMs was detected in 55.3% of cases, and was significantly associated with large tumor sizes, higher grade, advanced stage, positive LVI, and aggressive molecular subtypes. CD155 expression was significantly correlated with the densities of NK cells and TAMs in TME.

CONCLUSION

CD155 expression, high density of tumor infiltrating NK cells, and high density of stromal TAMs contribute to progression of IBC. CD155 can play an important immunoregulatory role in the TME.