Diagnostic utility of the B-cell lineage markers CD20, CD79a, PAX5, and CD19 in paraffin-embedded tissues from lymphoid neoplasms.

The specificity and sensitivity of CD19, CD20, CD79a, and PAX5 for detection of B-cell lineage lymphoma/leukemia derivation was determined on tissue microarrays containing 148 Hodgkin lymphomas, 358 B-cell and 16 T-cell lymphomas, 50 myelomas, and 69 acute leukemias. In mature lymphoid neoplasms, receiver-operating characteristic curve analysis showed CD20 to be the most sensitive, and CD20 and CD79a the most specific markers for B-lineage derivation. CD19 had the weakest specificity, because it was expressed in 3 T-cell lymphomas, but its sensitivity was better than CD79a. In Hodgkin lymphoma cases, the presence of B-cell markers in Hodgkin and Reed-Sternberg cells decreased in the following order: PAX5>CD20>CD79a>CD19. CD19 and PAX5 were not detectable in myelomas. In acute leukemia, CD20 turned to be the most specific, and PAX5 and CD19 the most sensitive markers for B-lineage derivation. In conclusion, an optimal B-cell lineage panel for daily routine on paraffin-embedded tissues should consist of CD20 and CD79a, and eventually, PAX5 for mature lymphoid neoplasms and PAX5 and CD19, and eventually, CD20 in (acute) precursor cell leukemias, because they cover most of the sensitivity and specificity needed.