The mouse monoclonal antibody p40 [BC28] recognizes an epitope unique to the p40 protein and may have applications in cases where p63 has traditionally been used. To date, p63 [clone 4A4] has been a frequently used marker for lung squamous cell carcinoma (SCC), as well as for bladder, breast, prostate, and head and neck cancers. p63 [4A4] recognizes both the p63 and p40 proteins (1). As a result, p63 [4A4] has proven to be a sensitive marker for lung SCC; however, it suffers from specificity limitations due to reactivity in a subset of lung adenocarcinomas (ADC). In contrast, p40 is selectively expressed in lung SCC, offering an opportunity for improved specificity (2). p40 (M) [clone BC28] recognizes an epitope unique to p40, which may result in diminished reactivity in lung ADC and increased specificity.
In recent studies, staining with a rabbit polyclonal anti-p40 antibody was equivalent to p63 [4A4] in sensitivity for lung SCC, but p40 exhibited markedly superior specificity due to staining in fewer cases of lung adenocarcinoma compared to p63 (1-3). This new mouse monoclonal anti p40 [BC28] demonstrated similar sensitivity and specificity, staining 97% (65/67) cases of lung SCC and 0% (0/71) cases of lung ADC (see Performance Characteristics). p40 has also been reported in combination with TTF-1 in a method to improve specificity for SCC vs. ADC, while preserving limited tissue specimens (3,4).
Changes in expression of p40 have been implicated in other neoplastic tissues, including bladder, prostate, breast and head and neck cancers (5-8). p40 (M) [BC28] was found to be a sensitive marker in each of these tissues (see Performance Characteristics). Studies have strongly supported the routine use of p40 as an alternative for p63 (1,2).