Why Doesn't the Immune System Target Tumours?

Recently some people told me about how an Italian cardiologist is making a big fuss out of the fact that when he removes a tumour he finds fungal infections around it, the implication being the fungal infection is causing the tumour. Classic case of mis-attribution of cause. Despite the claims of the news article and\or researchers, this is not news. By way of example, look at the following graphic which is drawn from this research piece.

The article was published in November 2007. Yes, scientists love to claim they were the first to make the discovery! If you scroll down the link above you can download a powerpoint presentation pertaining to this issue. To gain some insight into why this finding is so important, read on.