Myriad Genetics' ($MYGN) stock dropped 9% on Sept. 30, driven down by investors reacting to what appeared to be a proposed 48% Medicare reimbursement cut for one of the company's signature cancer diagnostic tests. It turns out there was no reduction, as the number came from a clerical error. Myriad was quick to advertise what happened, a major analyst firm upgraded the stock and then the price rebounded, closing Tuesday at $25.31, up 7.7%. But the one-day investor mini-panic over Myriad's situation underscored the industry's vulnerabilities once insurance coverage becomes uncertain. Story