US STOCKS-Futures down slightly as trade, inflation worries persistReuters... * Pfizer drops as quarterly revenue misses estimates. * Fed begins two-day policy meeting. * Oil slips on worries about Iran sanction. * Futures down: Dow 0.13 pct, S&P 0.04 pct, Nasdaq 0.08 pct (Adds comments, details, updates prices). By Sruthi ...and more »