J.K.
I haven't made this in years since my kids were young, but once I put in some cream cheese, and it was awesome!! About a half of a big block. Anyway, I continued to make it that way until they decided that they hated pasta with tuna.
Oh and for the bread crumbs, I used to tear apart some bread, and dip it in melted butter, and layer it on top of the tuna casserole before I baked it, butter side up. It will get all crispy and yummy!