For a long time, researchers who were curious enough to ask were told that HeLa cells were named after "Helen Lane" or "Helen Larson." Medical journals wrote about the line and a few did mention Henrietta's real name, but few people paid attention. That part just wasn't considered important.
The real Henrietta Lacks was a young African-American mother living outside of Baltimore, Maryland. While pregnant with her fifth child, she felt what she described to cousins as a "knot." After childbirth, Lacks experienced abnormal bleeding. Her doctor discovered a lump on her cervix and sent a sample of it to a lab. The result was a diagnosis of cervical cancer. The only hospital in the area at the time that would treat African-American patients was Johns Hopkins, so that's where Lacks went for treatment.
While her husband and children often waited in the car outside, she endured radiation treatments (which were done at the time by inserting tubes of radium around her cervix and sewing them into place) as well as X-ray treatments. The cancer spread despite these and other treatments, however, and caused Lacks horrible pain. She died in the hospital at the age of 31 on October 4, 1951. She had been diagnosed just nine months earlier.
During her radiation treatments, a doctor removed some tissue samples from Lacks' cervical tumor. She had signed the usual forms consenting to treatment for her cancer, but was not asked for her permission to remove the tissue samples, nor was she informed that it had been done, but this wasn't unusual. The tissue was sent to Dr. Gey in the Tissue Culture Laboratory at Johns Hopkins. Dr. Gey had been trying to grow human cells in the lab for decades, but they always died within a few days. Lacks' cells were unique. He isolated one of them and got it to divide -- and it just kept going. He named the line HeLa.