* Staples, Home Depot fall after earnings
* More AstraZeneca investors disprove of Pfizer rejection
* Aeroflex jumps, to be acquired by Cobham for $1.46 bln
* Futures up: Dow 10 pts, S&P 0.75 pt, Nasdaq 4.25 pts
By Chuck Mikolajczak
NEW YORK, May 20 (Reuters) - U.S. stock index futures were little changed on Tuesday, after the S&P 500 advanced for two straight days and investors assessed some of the final corporate results of earnings season.
* Home Depot lost 1.6 percent to $75.25 in premarket trade after the home improvement retailer reported lower-than-expected quarterly sales as its spring selling season got off to a slow start.
* Staples Inc tumbled 10.6 percent to $11.97 after the office supply retailer posted first-quarter earnings and forecast a decline in sales in the current quarter.
* U.S. stocks rose on Monday, with a rally in high-growth names among Internet and biotech shares pushing the Nasdaq to a gain of nearly 1 percent, as investors shrugged off recent concerns about stock valuations and the economy's growth prospects.
* S&P 500 e-mini futures 0.75 point and were roughly even with fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average e-mini futures gained 10 points and Nasdaq 100 e-mini futures 4.25 points.
* U.S.-listed shares of AstraZeneca advanced 2.1 percent to $72.10 in premarket after its twelfth largest shareholder, Schroders, joined a chorus of investor disapproval over its rejection of a takeover offer by Pfizer and urged it back into talks.
* Aeroflex Holding Corp jumped 25.8 percent to $10.45 before the opening bell. British aerospace and defense supplier Cobham is buying the U.S. communications equipment maker for $1.46 billion.
* The pan-European FTSEurofirst 300 index slipped on Tuesday as Vodafone, the world's second-largest mobile network operator, sank after reporting huge impairment costs.
* MSCI's broadest index of Asia-Pacific shares outside Japan slipped about 0.3 percent. But Japan's benchmark Nikkei stock average bucked the downtrend to break a four-session losing streak. (Editing by Bernadette Baum)