The Shadow Chaser by John Matthews
Description from Amazon:
Andre Lemoine, one of the world's leading geneticists, is on the verge of the medical breakthrough of the century: a link with rare primates that could unlock a vital key in the search for a cure for AIDS and cancer.
But part of Andre's quest is driven by a pressing medical threat within his own family, and when his breakthrough brings him into conflict with two ambitious ruthless rivals - it plunges Andre into the race of his life; a race which takes Andre from the dark jungles of Africa and Brazil to the seamy backstreets of Paris and Philadelphia. A nightmare world of thieves, hookers and pimps, lab bombers and FBI agents - far removed from the safety of his lab bench.
For Andre the stakes have never been higher. Because, as the threat to those Andre loves looms stronger, it becomes a race through the shadows of his family's dark past to, ultimately, face death head-on.