To investigate the requirement for Lpd in metastasis, we tested the effect of reducing Lpd expression in MDA-MB-231-LM2 cells (further referred to as LM2), a highly metastatic derivative of MDA-MB-231 breast cancer cells,26 on their ability to metastasize from an orthotopic mammary tumor to the lungs. The gene discussed is RAPH1; the disease is breast carcinoma.