Tumor B7-H1 and B7-H3 Expression in Squamous Cell Carcinoma of the Lung

Aberrant expression of immunomodulatory proteins B7-H1 and B7-H3 by malignant cells may contribute to tumoral immune evasion. Immunohistochemistry for B7-H1 and B7-H3 was performed on 214 resected pulmonary squamous cell carcinoma specimens: 42 of 214(19.6%) were positive for B7-H1, and 189 of 214(88.3%) were positive for B7-H3. These markers do not have independent prognostic value but are commonly expressed by tumor cells in pulmonary squamous carcinomas. Background: Pulmonary squamous cell carcinoma has a poor prognosis, and new therapeutic targets are needed. The aberrant expression of the immunomodulatory proteins B7-H1 and B7-H3 by malignant cells may contribute to tumoral immune evasion. Data about the expression of these proteins by squamous cell carcinoma of the lung are limited. Materials and Methods: Immunohistochemistry for B7-H1 and B7-H3 was performed on 214 resected pulmonary squamous cell carcinoma specimens. Results: At the last follow-up, 171 of 214 (80%) of patients were deceased (median survival time, 3.76 years). Forty-two (19.6%) of 214 cases showed positivity with B7-H1, with a range of 5% to 60% of cells that stained positively. A total of 189 (88.3%) of 214 cases showed positivity with B7-H3, with a range of 5% to 80% of cells staining positively. By using multivariate analysis, no degree of B7-H1 or B7-H3 positivity was significantly associated with patient outcome. Conclusions: Although B7-H1 and B7-H3 are not of independent prognostic value, they are commonly expressed on a subset of tumor cells in pulmonary squamous cell carcinomas. Known interaction of the B7-H proteins with cytotoxic T-lymphocyte antigen-4 may make them attractive candidate biomarkers for response to immunomodulatory therapeutics, eg, ipilimumab, and warrants further study. Clinical Lung Cancer, Vol. 14, No. 2, 157-63 (c) 2013 Elsevier Inc. All rights reserved.