B7-H3 expression in NSCLC and its association with B7-H4, PD-L1 and Tumor Infiltrating Lymphocytes

Background and Purpose: <p>The immune checkpoint PD-1 and its receptor B7-H1 (PD-L1) are successful therapeutic targets in cancer but less is known about other B7 family members.  Here, we determined the expression level of B7-H3 protein in non-small cell lung cancer (NSCLC) and evaluated its association with tumor infiltrating lymphocytes (TILs), PD-L1, B7-H4 and major clinico-pathological characteristics is in 3 NSCLC cohorts.</p> <p>Experimental design:</p> <p>We used multiplexed automated quantitative immunofluorescence (QIF) to assess the levels of B7-H3, PD-L1, B7-H4 and TILs in 634 NSCLC cases with validated antibodies. Associations between the marker levels, major clinico-pathological variables and survival were analyzed.</p> <p>Results: </p> <p>Expression of B7-H3 protein was found in 80.4% (510/634) of the cases. High B7-H3 protein level (top 10 percentile) was associated with poor overall survival (p <0.05). Elevated B7-H3 was consistently associated with smoking history across the 3 cohorts, but not with sex, age, clinical stage and histology. Co-expression of B7-H3 and PD-L1 was found in 17.6% of the cases (112/634) and with B7-H4 in 10% (63/634). B7-H4 and PD-L1 were simultaneously detected only in 1.8% of NSCLCs (12/634). The expression of B7-H3 was not associated with the levels of CD3, CD8 and CD20 positive TILs.</p> <p>Conclusion:</p> <p>B7-H3 protein is expressed in the majority of NSCLCs and is associated with smoking history. High levels of B7-H3 protein has a negative prognostic impact in lung carcinomas. Co-expression of B7-H3 with PD-L1 and B7-H4 is relatively low, suggesting a non-redundant biological role of these targets.

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