Without a doubt dogs can do this. I have always had a dog/cat around me as I do not believe we were meant to live 'separate' from animals, being animals ourselves. Animals are far more in tune with what we call the 'unseen' that we are sometimes sceptical about.They enrich life in an amazing way. To animals, the 'unseen' is a perfectly normal part of life, which is why they often know well before hand if an unpleasant event is going to occur. As well as smelling the cancer, the dog knows that this is a potential threat, which is why a dog can be very pushy about drawing attention to it. In animals, there is a much more 'smoother'and open flow between their conscious and their subconcious minds, whereas we tend to block ours, as we are drawn in to mundane monotonous everyday tasks. And we have the nerve to think we are 'superior' to them.