Many investors expected today's move in GlaxoSmithKline (NYSE:GSK), with shares of GSK stock plunging more than 8% in early afternoon trading. That's because, on Friday, a Delaware judge ruled that expert witnesses would be allowed to testify in court that the company's discontinued Zantac heartburn medication may have caused cancer. This ruling will allow 70,000 lawsuits to proceed, alleging that Zantac caused cancer. Many investors in the U.K.-based drugmaker hoped the courts would dismiss this request, b ...