HeLa cells are an immortal line of cells taken from the Cervical Cancer of an unsuspecting African American woman called Henrietta Lacks in 1951. She was a poor 31 year old who lay dying in the segregated ward in Baltimore at the John Hopkins Hospital.

The sample of the tumor cells was taken by the hospitals gynecologist and passed on to Dr George Gey. Dr Gey in his quest to cells of human diseases in his laboratory had so far failed to keep alive any specimens, as human cells died in laboratory conditions. To his amazement the HeLa cells named after the initials of Henrietta Lacks survived.

Most laboratories today which maintain tissue cultures are using HeLa cells to further research. They helped in the development of the polio vaccine and the cells have been cultured so many times that they now weigh several times their unsuspecting donor's weight.