CALCA and prostate adenocarcinoma: The circulating levels of CGRP in prostatic adenocarcinoma correlate with the presence of diarrhea, and both the plasma levels of CGRP and the associated diarrhea have been found to be resistant to octreotide, a somatostatin analog commonly used in an attempt to mitigate tumor-associated symptoms (Shulkes et al., 1991).