Are the colonial marines canon in the alien world?

From my understanding, interviews and such, the creative team went to a lot of trouble, with Fox's blessing, to write a story that would take place between 'Aliens' and 'Alien 3'; a story that would be, for all intents and purposes, considered canon.

Gearbox, along with Sega, worked closely with 20th Century Fox and Ridley Scott when designing the game so yea it's canon. [url=http://www.nowgamer.com/news/1021167/aliens_colonial_marines_has_ridley_scott_and_sid_mead_input.html]Aliens Colonial Marines Has Ridley Scott And Sid Mead Input[/url]

You know Sir Riddley Scott still has to keep his fans satisfied not the other way around. It really depends on how it is going to affect the story line/timeline. Its only when you cross franchises together is a roll of the dice.