Are HeLa cells edible?
I think HELA cells are edible, although from moral point of view this would be cannibalism.

Despite they are cancer cells, they are safe for foreign organism, because any ate matter is destroyed. Even if these cells were implanted into another being by surgery, they will be safe since immunity will recognize them as foreign and kill. They are much less cancerous for recipient than just foreign.

Remember, then when we are eating meat, we don't care if cow or pig had cancer. Even if we avoid eating explicit tumors, we can still eat metastatic cells from sick animals. I think this happening all the time and has no consequences.

Simultaneously HELA cells are dangerous for other cell cultures in laboratory. There were several cases, when other cultures were infected by HELA cells and crowd out. HELA cells were traveled by air and on objects unexpectedly. Scientists were not ready for this phenomenon.