A HeLa cell (also Hela or hela cell) is an immortal cell line used in medical research.
HeLa cells are termed "immortal" in that they can divide an unlimited number of times in a laboratory cell culture plate as long as fundamental cell survival conditions are met (i.e. being maintained and sustained in a suitable environment).
These cells proliferate abnormally rapidly, even compared to other cancer cells.
The cell line was derived from cervical cancer cells taken from Henrietta Lacks, who died from her cancer in 1951.
(From the Wikipedia).