It would be great to transfer breast tissue from one to the other, but technically this would be predicament with breast cancer.
It is possible to perform breast enlargement by fat grafting (taking fat from another place on the body). It would be better to take that fat from your abdomen or legs. Fat grafting is a new technique for breast augmentation and so far we have seen changes in mammograms which are easily identified as benign (not cancerous) but this has not been studied long term. If you are young, you don't have much fat tissue in your breasts - they are more fibrous so it is difficult to use the other breast as a donor site for fat anyways. Good luck!