How can merely doing genetic engineering on one cell lead to curing of oral cancer which contains many cancerous cells. Similarly how can any genetic disorder be treated using genetic engineering as they can't do genetic engineering on trillions of cells present in a person

How can merely doing genetic engineering on one cell lead to curing of

1.	How can merely doing genetic engineering on one cell lead to curing of oral cancer which contains many cancerous cells. Similarly how can any genetic disorder be treated using genetic engineering as they can't do genetic engineering on trillions of cells present in a person
Answer» How can merely doing genetic engineering on one cell lead to curing of oral cancer which contains many cancerous cells. Similarly how can any genetic disorder be treated using genetic engineering as they can't do genetic engineering on trillions of cells present in a person