* EU vote campaigning suspended after lawmaker shot dead
* Looming Brexit vote has been rattling markets
* Energy shares down as oil tumbles
* Dow up 0.32 pct, S&P up 0.05 pct, Nasdaq down 0.13 pct (Updates to late afternoon)
By Lewis Krauskopf
June 16 (Reuters) - Wall Street erased losses on Thursday as investors sought to digest the implications of a British lawmaker's death on the country's impending referendum to leave the European Union.
The S&P 500 index edged higher after five straight sessions of losses, a day after the Federal Reserve left interest rates unchanged but signaled it still planned two hikes this year.
A British member of Parliament was shot dead in the street in northern England, causing the temporary suspension of campaigning for next week's referendum on EU membership. The lawmaker, Jo Cox, had been a vocal supporter of Britain remaining in the European Union.
The prospect of Britain's voting to leave in the June 23 referendum has been rattling markets.
"We're seeing a move in the pound rallying off its lows, the Treasuries coming off of their highs and the stocks coming off of their lows because of that," said Lou Brien, market strategist at DRW Trading in Chicago. "People are anticipating that this could be one of those things that turns a vote back in favor of remain."
The Dow Jones industrial average was up 55.81 points, or 0.32 percent, at 17,695.98, the S&P 500 gained 1.02 points, or 0.05 percent, at 2,072.52 and the Nasdaq Composite dipped 6.32 points, or 0.13 percent, at 4,828.62.
A sixth-straight day of losses would mark the S&P's worst losing streak since August.
Global stocks have been under duress for a week amid looming uncertainty about the British vote and a focus on central bank policy.
Fed Chair Janet Yellen on Wednesday acknowledged the need to see clear signs of economic strength before lifting rates.
The S&P is up more than 1 percent for the year, rebounding since mid-February with help from higher oil prices.
However, on Thursday energy shares were one of the worst-performing sectors, down 0.2 percent, as oil slumped to one-month lows.
The CBOE Volatility index, the most notable gauge of Wall Street anxiety, shot up to a 4-month high. After weeks of calm, the index has risen significantly this week.
Merck shares rose 2.5 percent, propping up the Dow and the S&P, after positive clinical trial results for cancer drug Keytruda.
Shares of Cavium fell 17.6 percent after the chipmaker said it would buy network equipment maker QLogic for about $1.36 billion. QLogic shares rose 9.5 percent.
NYSE declining issues outnumbered advancers by a 1.55-to-1 ratio ; on the Nasdaq, a 1.75-to-1 ratio favored decliners.
The S&P 500 posted 13 new 52-week highs and 4 new lows; the Nasdaq recorded 19 new highs and 50 new lows. (Additional reporting by Karen Brettell and Saqib Iqbal Ahmed in New York and Yashaswini Swamynathan in Bengaluru; Editing by Don Sebastian and Nick Zieminski)