Juno Therapeutics Inc. is widely tipped as a potentially hot IPO if and when the immunotherapy company decides to go public. The question is whether VC enthusiasm has left enough upside for public investors.

Juno, which was founded only last year, already closed a $134 million B round this month, on top of the $176 million it raised in three closes of an A round from a VC syndicate that included Arch Venture Partners