Wall St extends losses; biotechs drag Nasdaq
* The Dow Jones industrial average dropped 38.24 points, or 0.41 percent, to 9,242.73. The Standard & Poor's 500 Index dropped 5.95 points, or 0.59 percent, to 996.77. The Nasdaq Composite Index dropped 16.52 points, or 0.83 percent, to 1,976.53.
(Reporting by Chuck Mikolajczak; Editing by Padraic Cassidy)