* Futures off: Dow 21 pts, S&P 2.5 pts, Nasdaq 3 pts
NEW YORK, March 23 (Reuters) - U.S. stock index futures ticked lower on Monday following strong gains in major indexes last week, as investors eyed negotiations over the future of Greece in the euro zone and as oil prices fell further.
* German Chancellor Angela Merkel and Greek Prime Minister Alexis Tsipras were set to meet in Berlin, and Tsipras' list of reform proposals will be given to the Eurogroup of euro zone finance ministers. Merkel has repeatedly said nobody should expect a solution from their Monday meeting.
* Oil prices fell further, with Brent dropping 1 percent below $55 a barrel and U.S. crude down 2 percent to $45.60, after top exporter Saudi Arabia said it would mull cutting output if other producers outside OPEC do so, too.
* Gilead Sciences shares fell 3.8 percent in premarket trading. A report by Bloomberg said the company told healthcare providers nine patients taking its hepatitis C drugs Harvoni or Sovaldi, along with a heart treatment, developed abnormally slow heartbeats and one died of cardiac arrest.
* Traders will likely keep an eye on the U.S. dollar, which remains in a strong footing as the Federal Reserve is seen tightening monetary policy some time later this year, diverging from most major central banks which are easing policy. The 20-day correlation between the dollar index and S&P 500 e-mini futures sits at -0.8.
Futures snapshot at 7:34 a.m. EDT (1134 GMT):
* S&P 500 e-minis were down 2.5 points, or 0.12 percent, with 88,212 contracts changing hands.
* Nasdaq 100 e-minis were down 3.25 points, or 0.07 percent, in volume of 17,149 contracts.
* Dow e-minis were down 21 points, or 0.12 percent, with 15,422 contracts changing hands.
Reporting by Rodrigo Campos; Editing by Bernadette Baum