NEW YORK, July 23 (Reuters) - U.S. stock index futures dropped in late trade on Thursday as a string of disappointing results from companies, including Amazon.com Inc and Microsoft Corp, sparked caution.
* Nasdaq futures fell 8.50 points, while S&P 500 futures shed 3.70 points, and Dow futures slipped 25 points. (Reporting by Ellis Mnyandu; Editing by Jan Paschal )