Short answer: Yes.
Both home and commercial brewers substitute hops all the time. However, there is a lot to consider.
a) Substituting bittering hops - early in the boil - you need to calculate the amounts based on difference in AA%
b) Substituting dry hops - in the carboy - you need to pick hops that have similar flavors.
c) Substituting aroma hops - late in the boil - you need to factor in both a and b.
There are lots of charts available concerning substitutions: http://www.rooftopbrew.net/?page_id=239
For instance, Centennial is sometimes described as "super cascade". Adjusted properly, you can use it in recipes that call for Cascade.