Light micrograph of HeLa cells. Cell nuclei (blue) and actin fibres and tubulin in the cell cytoskeleton (both yellow) are visible here. HeLa cells are an immortal human epithelial cell line derived from a cancerous tumor of the cervix (adenocarcinoma). It was established in 1951 from a biopsy taken from Henrietta Lacks and was the first human cell line to survive and grow in the laboratory. Henrietta's cells were originally used in this way without permission from her or her family which raises issues about ethics and privacy. HeLa cells have been used extensively around the world in many different fields of research, including cancer research, immunology and vaccine development. Width of image is 200 micrometres.