NEW YORK, Oct 23 (Reuters) - U.S. stocks extended losses on Friday, with the Nasdaq turning negative, weighed by biotechnology and chipmaker shares including Broadcom Corp (BRCM.O: Quote, Profile, Research).

Among the top decliners was software company CA Inc (CA.O: Quote, Profile, Research), down 11 percent to $21.28.

The Nasdaq rose more than 1 percent at the open lifted by gains in Amazon.com (AMZN.O: Quote, Profile, Research) and Microsoft Corp (MSFT.O: Quote, Profile, Research).

The Dow Jones industrial average .DJI dropped 65.90 points, or 0.65 percent, to 10,015.41. The Standard & Poor's 500 Index .SPX dropped 7.98 points, or 0.73 percent, to 1,084.93. The Nasdaq Composite Index .IXIC dropped 1.89 points, or 0.09 percent, to 2,163.40. (Editing by Kenneth Barry)