The specificity of this monoclonal antibody to its intended target was validated by HuProtTM Array, containing more than 21,000, full-length human proteins. The PAX5 gene is a member of thepaired box (PAX)family of transcription factors. The central feature of this gene family is a novel, highly conservedDNA-binding domain, known as thepaired box. The PAX proteins are important regulators in early development, and alterations in the expression of their genes are thought to contribute toneoplastic transformation. The PAX5 gene encodes theB-celllineage specific activator protein (BSAP) that is expressed at early, but not late stages of B-cell differentiation. Its expression has also been detected in developing CNS and testis; therefore, PAX5 gene product may not only play an important role in B-cell differentiation, but also in neural development andspermatogenesis.