Major noise from a Gibson semi-hollow! Help!

Hi experts. Hope you can help.

I recently took out my '92 Gibson Tennessean (it's a remake of the old Gretsch Tennessean) and plugged into a Korg processor and then to a small Marshall practice amp. I'm getting major buzzing from the guitar (yes, I've isolated the source) -- when I touch the metal part of the cable or the humbucker pickup with my finger, then buzzing goes away.

Is there something wrong with the guitar's wiring?

Thanks!!!