Short answer is yes you can. But it really depends on what style you are going for also. Using more malt extract doesn't necessarily mean that you your beer will be better, stronger, yes, but not always better. Good luck with it and let us know how it comes out.
Also let us know what else you are using in there, i.e. any specialty grains, what hops?
"Yes, I am a pirate two hundred years too late. The cannons don't thunder there's nothin' to plunder,
I'm an [under] forty victim of fate, Arriving too late, arriving too late."