* Oil stocks underperform after overnight oil prices' drop
* Sun Corp soars after report FBI enlisted help of its subsidiary
* Hitachi Transport soars on report it will tie up with Sagawa
* U.S. jobs data eyed - traders
By Ayai Tomisawa
TOKYO, March 30 (Reuters) - Japan's Nikkei share average edged down on Wednesday morning as the dollar dropped against the yen after U.S. Federal Reserve Chair Janet Yellen called for caution on raising interest rates.
The Nikkei dropped 0.4 percent to 17,031.54 in midmorning trade.
Federal Reserve Chair Janet Yellen said on Tuesday the U.S. central bank should proceed "cautiously" as it looks to raise interest rates, because inflation has not yet proven durable against the backdrop of looming global risks to the U.S economy.
U.S. stocks rose overnight, but with the stronger yen hurting sentiment, Japanese equities were sold.
Traders said that the Fed's monetary policy will likely remain a big catalyst in the market, and U.S. jobs data, which is scheduled to be released on Friday, is cautiously watched.
"Most people will likely stay on the sidelines before they take positions, and the jobs data is carefully monitored because it could move the currency market," said Hikaru Sato, a senior technical analyst at Daiwa Securities.
Oil shares underperformed, with Inpex Corp falling 2.2 percent and Japan Petroleum Exploration shedding 1.5 percent after oil prices tumbled overnight before rebounding in Asian morning trade.
Exporters languished after the dollar dipped to 112.79 yen , recoiling from a two-week high of 113.805.
Toyota Motor Corp fell 0.7 percent and Nissan Motor Co shed 1.4 percent.
Outperforming the market was electronics maker Sun Corp , jumping as much as 22 percent to a near six-month high. The Nikkei reported that the U.S. Federal Bureau of Investigation may have enlisted the help of Israel's Cellebrite, which was acquired by Sun Corp, to access information on an encrypted iPhone belonging to a suspect in a terrorism investigation.
Last week, Sun Corp's shares soared after the Yedioth Ahronoth newspaper reported that the provider of mobile forensic software is helping the FBI's attempt to unlock an iPhone used by one of the San Bernardino, California shooters.
Also outperforming the market was Hitachi Transport System , which jumped 9 percent after the Nikkei business daily reported that the logistics company will form a "comprehensive partnership" with truck delivery firm Sagawa Express.
The broader Topix dropped 0.2 percent to 1,374.76 and the JPX-Nikkei Index 400 declined 0.2 percent to 12,417.73. (Reporting by Ayai Tomisawa; Editing by Eric Meijer)