* FTSEurofirst 300 up 0.7 pct
* Ukraine rebels hand over black boxes from Malaysian plane
* Actelion top riser as results revive M&A speculation
By Francesco Canepa
LONDON, July 22 (Reuters) - European stocks rebounded on Tuesday with traders hoping for an easing of tensions between Russian and the West after pro-Russian rebels agreed to hand over the black boxes from the Malaysian plane downed in Ukraine last week.
By 0721 GMT, the pan-European FTSEurofirst 300 index was up 0.7 percent at 1,364.75 points.
Heightened tensions between Russia and the West following the plane incident and the prospect of harsher Western sanctions on Russia, combined with escalating violence after Israel's ground offensive in Gaza, have weighed on equities in the past week and traders expected the market to remain jittery.
"There will probably be some relief early on but with some risk-off remaining," Mike Reuter, a broker at Tradition, said. "There's no resolution to the conflict. Fighting in Donetsk continues and the Gaza conflict is also ongoing."
European Union foreign ministers were scheduled on Tuesday to discuss further penalties against Russia, but the most they are expected to do is to speed up the implementation of sanctions against individuals, and possibly companies, agreed in principle last week before the plane was brought down.
"Co-operative steps from the pro-Russian rebels have soothed traders' fears that East-West relations are about to resemble the Cold War era," Capital Spreads dealer Jonathan Sudaria said in a trading note.
Actelion, Europe's largest biotech company, was the top FTSEurofirst 300 riser, gaining 4 percent after it hiked its 2014 profit forecast for the second time this year.
While the firm's chief executive said his strategy to stay independent was supported by shareholders, traders speculated on possible bids from larger firms such as AstraZeneca, Roche, GlaxoSmithKline or Novartis.
"Actelion is the answer to AstraZeneca's chronic pipeline shortage, GlaxoSmithKline's need for expansion and would be an easy morsel for Roche or Novartis to digest," Hobart Capital Markets trader Justin Haque said.
Elsewhere, corporate updates were less upbeat with French media group Publicis Group and Norwegian aluminium producer Norsk Hydro both disappointing.
Their shares fell 5 percent and 2.4 percent, respectively.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Editing by Louise Ireland)