So many things wrong with that article.
For one, it's not a cell that's a laser. It's a cell that's being used as basically a living LED inside a series of mirrors/lenses that is used to create a laser. Basically, it's not using a cell to create a LASER, but sticking a cell INSIDE a laser to act as the light source... When it's activated by another, higher energy laser.
As such, it has no future applications that I can see inside the body, as you would actually need to surgically implant the lenses around the cell you want to study.
Adding recombinant GFP to human cells, on the other hand, is something that's been around for at least the last 15 years- it's great technology, and it lets you do a lot with imaging cells. It's one of the techniques I use for determining the effectiveness of the drugs I design, and it has a lot of potential in easy sensing of certain cell states...
But using it as an activatable internal laser to treat diseases? I highly doubt it.
For one thing (as I mentioned earlier) it isn't a laser without the optics! They haven't created a "living laser"... Heck, they'd be better off using any of the luminescent proteins (firefly luciferase, etc) instead- then they wouldn't need the high energy pulse to feed the fluorescence.
GFP (or any other fluorophore) is always an energy loss- it takes in high energy light, and then emits much lower energy light in a non-direction specific manner, losing both energy and coherence.
I also love how the article cuts out the second part of Bern's discussion on the topic:
Michael Berns wrote:
But he says that the technique might more feasibly be used to study individual cells than for medical applications. He points out that external light is needed to stimulate the laser action, which would be difficult in the body, potentially limiting the technique to thin-tissue systems or cells in culture or suspension.