US STOCKS-Wall St drops as China hits commodities, Greece crisis drags
* Euro zone summit on Greece proposal to start at 1600 GMT
* China slowdown fears drags commodities towards 2015 lows
* AMD slumps after cutting quarterly revenue forecast
* Shake Shack falls after Morgan Stanley rating cut
* Indexes down: Dow 1.15 pct, S&P 1.12 pct, Nasdaq 1.73 pct (Adds details, comment, updates prices)
By Tanya Agrawal
July 7 (Reuters) - U.S. stocks fell more than 1 percent on Tuesday, with the S&P 500 index trading below a key technical mark, as concerns of a slowdown in China weighed on commodity prices and investors fretted over aid talks for Greece as it runs out of cash.
The declines pushed the S&P and the Dow Jones Industrial Average into negative territory for the year, while the Nasdaq fell to a two-month low a day ahead of the start of the earnings season in the United States.
A euro zone summit, starting at 12 p.m. ET (1600 GMT) in Brussels, will decide if Greek Prime Minister Alexis Tsipras' latest proposal is enough to keep the country in the euro zone. Continuación...