Genentech laughs off $43.7 billion buyout offerYou're forgiven if you don't know there's a company a few miles north of Google that pulls in more than $10 billion a year selling drugs. Genentech makes the cancer treatment Avastin, the arthritis and lymphoma drug Rituxan, and the breast cancer fighter Herceptin, each of which bring in a few billion a year. Its stock, which trades under the symbol DNA, nearly touched $100 a share yesterday, a three-year high. Market cap is just over $100 billion, not far behind Google's $118 billion. Once you know all that, it's not surprising that the company nixed a buyout offer from Roche, its majority shareholder. San Francisco's bid to become the world's biotech center is moving more slowly than planned, but just you wait another ten years. These little drug companies are going to get a lot bigger.