Why is there soy in my tuna?

I am a big fan of Dr. Oz and being so he brought up the topic of soy and breast cancer. Since cancer runs in my family I do what I can to watch what I eat ( sometimes it is cake that I watch... I am not perfect, it is yummy...and there goes my diet once again....) Anyways, he said that eatting the whole soy bean apears to be safe, but having it added to things in in not it's whole form might not be healthy. Soy converts into estorgen, in case you did not know this. So I was reading lables and was very surprised to find soy in my tuna. Look in your pantry and see if it is in yours. It is found in cereal, salad dressing, some breads and who knows what else. I cannot help but wonder if this is safe for young girls? I will be calling the makers of my tuna tomorrow and ask them why is soy in there-- I bet they don't know, just seemed like a good idea. I want to buy food that is what it is, not made up of parts of everything, if I want that I know lunch meat is a good way to find all the fillers I can ever want ( hey, it does taste fine, just saying) . There was a cereal I once bought and loved it very much, then they got the idea to add lots of sugar to it and change up the product completely. I knew they did not sell the cereal well but that was due to how much they were trying to sell it for. Anyways, I wrote them and they responded with rudeness and they lost me from every buying any of their products again.
My rant is over, just wanted to point out to look at your tuna and see what you really have.