I have searched the net and I have not been able to come up with an clear answer.
Edit: Here is the para quoted from Nature http://www.nature.com/news/medical-research-cell-division-1.13273 "So began WI-38, a strain of cells that has arguably helped to save more lives than any other created by researchers. Many of the experimental cell lines available at that time, such as the famous HeLa line, had been grown from cancers or were otherwise genetically abnormal. *WI-38 cells became the first 'normal' human cells available in virtually unlimited quantities to scientists and to industry and, as a result, have become the most extensively described and studied normal human cells available to this day".*