TO GO WITH AFP STORY BY MARC BURLEIGH -

TO GO WITH AFP STORY BY MARC BURLEIGH - A laboratory worker gives back ticks into a tube after exctracting saliva from them, at the molecular centre of Butantan Institute, in Sao Paulo, Brazil, on August 25, 2009. One of nature's repulsive little blood-sucking parasites, the tick, could yield a future cure for cancers of the skin, liver and pancreas, Brazilian researchers have discovered. They have identified a protein in the saliva of a common South American tick, Amblyomma cajennense, that apparently reduces and can even eradicate cancerous cells while leaving healthy cells alone. AFP PHOTO/Mauricio LIMA (Photo credit should read MAURICIO LIMA/AFP via Getty Images)