Okay no, that's not how it works at all. The differences in DNA between cancer cell and non-cancerous cell are negligable when compared to the differences between mother DNA and zygote/fetal DNA. If those fetal cells escaped the placenta or uterus, the mother's immune system would attack them because they're not recognized as "self."
Sure, it's the mother's egg, until it isn't. It quickly becomes something else biologically at the moment of fertilization.
Again, the mother isn't making the cells, the zygote/fetal cells are making themselves.
It's clear you have some beliefs that are not backed up by science. You also did not understand my analogies. I'm sure you'll eventually learn this stuff in school.
Nope, I'm out. Bye