By Benjamin Horney (March 3, 2016, 3:55 PM EST) -- Fujifilm Holdings Corp. and Canon Inc. have emerged as front-runners to buy Toshiba Corp.'s struggling medical equipment unit, The Wall Street Journal reported on Thursday, with a deal expected to potentially be worth as much as $6 billion. The end of this week marks the finale of the second round of bidding, the report noted, and Toshiba could choose a single bidder to enter into exclusive negotiations with as soon as next week. The news comes after reports earlier this week had a sale of the unit worth as much as $4.4 billion, with other interested suitors including KKR & Co. LP and Konica Minolta Inc. Rumors that the unit was on the chopping block first sprouted in late January....