It will most likely work fine. There is the potential that a standard audio cable might allow RF interference into the signal but that's probably a groundless worry in most cases (pun intended). In fact, if the RF interference is high enough, it can even be induced into the DMX recommended data cable. Noise is noise.
Meanwhile, I think a little background is in order on the connector history.
So, the ANSI standard connector for DMX is a five pin XLR. The reason this was originally selected by David Cunningham at Colortran (and others) was because three pin XLR's were already used for microphone and other audio cables, four pin XLRs were used in many headset systems, so therefore due to the relative rarity of five pin XLR's, it would be unlikely that someone would see an audio connector and inadvertently plug it into a DMX circuit.
At the end of the day, DMX only uses three pins (pin one, two, and three). as a result, if you really wanted to use a three pin XLR for your DMX circuit, you could. A lot of cheap “disco “ lighting equipment does, in fact, use three pin XLR's already. Look on eBay or Amazon and you will see cheap lighting equipment and cords employing three pin XLR's.
