Expression of metastatic markers in invasive lobular breast cancer (LBC) cells. (a) Co-expression of osteopontin (green) in invasive lobular carcinoma (ILC) cells positive for vimentin (red). Asterisks mark in situ lesions. (b) LBC cells with activated c-Src (green) coexpress the bone metastatic marker osteopontin (red). (c) Cxcr4, a marker for lymph node metastasis, was weakly expressed in the in situ lesions (left) and strongly expressed in the vast majority of invasive cancer cells (middle and right).