There’s an interesting interview here (via Ta-Nehisi Coates) about an African-American woman named Henrietta Lacks whose cervical cancer cells were taken as samples in 1951, shortly before her death, and were found to reproduce in a culture so quickly and efficiently that they revolutionized research on human tissue. They called them HeLa cells, and her family knew nothing about it until twenty-five years later, when her daughter Deborah was contacted by researchers who were interested in getting a sample of her own cells.
There is no earthly way that Octavia Butler didn’t know about this when she was writing Dawn. The heroine with whom the frightening, inexplicable alien falls in love/lust mainly due to her body’s fascinating ability to develop tumors? I think that is what a metaphor looks like.