U.S. S&P 500 futures,the world's most liquid, tumbled as much as 2.5 percent to 4-month lows in Asian trade on Tuesday as the sell-off triggered by worries about inflation showed no sign of abating, indicating Wall Street could be set for another brutal day. Futures fell to as low as 2,542, the weakest levels since early October, and 11.7 percent below their record peak of 2,878.5 touched on Jan. 29. S&P futures were last down 1.6 percent while Dow futures were last down 2.2 percent. The slide added to sharp falls over the past week. The S&P 500 index and...