Amplification of oncogenes in mammary carcinoma shown by fine-needle biopsy.
 A procedure that measures the amplification of oncogenes in human cancer cells is described.
 The cells were obtained by fine-needle biopsy to allow repeated sampling from individual metastases.
 A drawback was the low number of cells obtained, but this could be overcome by using a slot-blot hybridization technique to measure gene amplification.
 Two patients with mammary cancer (primary tumors or metastases), analyzed for the levels of amplification of the oncogene erb-B2, are described in detail.
 This technique is suitable for analyzing alterations occurring during cancer progression and for identifying subgroups of mammary cancer with different characteristics.
