Instead, the overwhelming majority of B-MF derived from highly FACS-purified CD45.2+ B-cell precursors of the B-cell lineage tracer Mb1-EYFP+ mice only expressed CD45.2 after in vitro co-differentiation with CD45.1+ monocyte/macrophages or adoptive transfer in tumor-bearing CD45.1+ mice. This evidence concerns the gene CD79A and neoplasm.