An immunohistochemical analysis of a newly developed, mouse monoclonal p40 (BC28) antibody in lung, bladder, skin, breast, prostate, and head and neck cancers.

Context: Immunohistochemistry is important to the pathologist for accurate diagnosis of lung cancer. In recent studies, a rabbit polyclonal p40 (RPp40) antibody demonstrated equivalent staining versus anti-p63 in lung squamous cell carcinoma, and superior specificity because it stains a lesser percentage of lung adenocarcinoma.

Objectives: To develop an anti-p40 mouse monoclonal antibody (MMp40) for immunohistochemistry, and to evaluate its sensitivity and specificity in normal and neoplastic tissues, with emphasis on lung cancer.

Design: The MMp40 (BC28) antibody was developed and tested for specificity and sensitivity on normal (n = 34) and neoplastic tissues (n = 493). Staining of MMp40, p63, and RPp40 were directly compared in lung cancers, and MMp40 was evaluated in breast, bladder, skin, prostate, and head and neck cancers. Benign prostate glands and prostatic intraepithelial neoplasia were also tested in a direct comparison of MMp40 versus p63.

Results: The MMp40 provided equivalent staining versus RPp40 and p63 in lung squamous cell carcinoma, but stained a lesser percentage of lung adenocarcinoma than p63 did. The MMp40 staining was observed in a greater percentage of urothelial carcinomas, squamous and basal cell skin cancers, and head and neck cancers of squamous cell origin. No breast-infiltrating ductal carcinomas or prostatic adenocarcinomas were stained. The MMp40 expression in basal cells of prostate glands and prostatic intraepithelial neoplasia were almost identical to those of p63.

Conclusion: The MMp40 (BC28) monoclonal antibody is a high-quality screening antibody for determining squamous cell carcinoma in lung cancers, skin cancers of squamous or basal cell origin, squamous cell head and neck cancers, and urothelial carcinomas.