||B-Cell Transcription Factor
||Pax-5 is expressed primarily in pro-, pre-, and mature B-cells, but not in plasma cells. Pax-5 exceeds the specificity and sensitivity of L26 (CD20) because of its earlier expression in B-cell differentiation and its ability to detect all committed B-cells, including classic Hodgkin's lymphoma. It has not been detected in any multiple myelomas or solitary plasmacytomas and is negative in anaplastic large cell lymphoma of T- and null cell type (ALCL).
Labels the nuclei of basal or progenitor cells of stratified squamous and transitional epithelia. Useful as a myoepithelial marker for in situ vs infiltrating breast carcinoma and is lost in prostatic adenocarcinoma.