The first suspects would be the cables, the card reader and the card. Of course it can be the camera too, after all it's just a mass produced electronic device and all of them fail eventually. Some sooner, some later. My bet is that it's not the camera though.
This is a bit off topic, but if the culprit happens to be the card, then this is the rare occasion when shooting uncompressed raw trumps lossless compressed, since in uncompressed files only the corrupted byte is "broken" (or a few bytes), but in compressed files all the bytes after the "broken" one are garbage.