The pulmonary metastasis of mammaryadenocarcinomas in MMTV-PyMT mice depends on hematopoietic cells, includingCD4+ T cells, macrophages and TGFβsignaling.34 To verify therole of Bcl-3 in the pulmonary metastasis of cancer cells, we transferredwild-type (WT) bone marrow into lethally irradiatedBcl-3-sufficient or Bcl-3-deficient MMTV-PyMT mice. The gene discussed is BCL3; the disease is cancer.