And you said--
 

--there was protein in your blood and urine that they started a cancer search for.

That immediately makes me think you may be one of those people with a monoclonal gammopathy, which is known to cause neuropathy. This happens when rogue proteins are produced by the bone marrow--monoclonal antibodies, or M-proteins--which sometimes signal the beginning of a blood cancer process, but sometimes have uncertain clinical significance; in fact, there is a documented condition known as MGUS--monoclonal gammopathy of uncertain significance--in which neuropathy is quite common, as the monoclonals tend to react to components of peripheral nerve.

Take a look at:

http://neuromuscular.wustl.edu/antibody/mprotein.htm