Cyclic nucleotide phosphodiesterases in normal and malignant human tissues.

Biopsy samples were obtained from tumor tissue and surrounding normal tissue from the same organs of the same patients in 25 patients. Adequate studies could be performed on all parameters in 18 tissue pairs: 12 malignant melanomas, 4 sarcomas, and 2 others. Significantly higher levels of cAMP low affinity phosphodiesterases were found in the tumors as compared to the controls. Similar differences were seen in the high affinity cAMP phosphodiesterases, but these were of borderline significance. High affinity cGMP phosphodiesterase levels did not differ significantly between normal and neoplastic tissue samples. Low affinity cGMP phosphodiesterases were not detectable in either tissues. These studies together with earlier experimental findings suggest possible auxiliary therapeutic trials with phosphodiesterase inhibitors.