During the rise of Protestantism, for various unsubstantiated reasons the following parts were removed from the Bible.
The Book of Tobit
The Book of Judith
The Wisdom of Solomon
The Book of Sirach [Ecclesiasticus]
The Writings of Baruch
The First and Second Books of the Macabees
Two Chapters of Daniel and the Song of the Hebrew Children in the fiery furnace (Daniel 3:25-90)
My question is this : if 7 books + some chapters are missing from the KJV of today's Bible : What makes you think that other alterations in the form of mistranslations , additions etc.. weren't made ?