I really don't recommend using standard XLR cabling for DMX. DMX works much better using 120-ohm cabling as opposed to the 600-ohm cabling you're using for microphones. You'll get better reliability and performance.
Then again, I am running my DMX down 200 feet of 600-ohm cable down my main audio whip and it works just fine, not to mention all the other microphone cabling that goes on after that(up to another 100 feet maybe?). However, I am getting/building my own DMX cabling to my specifications soon. My suggestion: good labelling! Don't mix and match, you'll lose some of your top end using the 120-ohm cabling for microphones.