title: Extracellular activity of cyclic AMP-dependent protein kinase as a biomarker for human cancer detection: distribution characteristics in a normal population and cancer patients.
abstract: The overexpression of cyclic AMP (cAMP)-dependent protein kinase (PKA) has been reported in patients with cancer, and PKA inhibitors have been tested in clinical trials as a novel cancer therapy. The present study was designed to characterize the population distribution of extracellular activity of cAMP-dependent protein kinase (ECPKA) and its potential value as a biomarker for cancer detection and monitoring of cancer therapy. The population distribution of ECPKA activity was determined in serum samples from a Chinese population consisting of a total of 603 subjects (374 normal healthy volunteers and 229 cancer patients). The serum ECPKA was determined by a validated sensitive radioassay, and its diagnostic values (including positive and negative predictive values) were analyzed. The majority of normal subjects (>70%) have undetectable or very low levels of serum ECPKA. In contrast, the majority of cancer patients (>85%) have high levels of ECPKA. The mean ECPKA activity in the sera of cancer patients was 10.98 units/mL, 5-fold higher than that of the healthy controls (2.15 units/mL; P < 0.001). In both normal subjects and cancer patients, gender and age had no significant influence on the serum ECPKA. Among factors considered, logistic analysis revealed that the disease (cancer) is the only factor contributing to the elevation of ECPKA activity in cancer patients. In conclusion, ECPKA may function as a cancer marker for various human cancers and can be used in cancer detection and for monitoring response to therapy with other screening or diagnostic techniques.
authors.affiliation: Division of Clinical Pharmacology, Department of Pharmacology and Toxicology, University of Alabama at Birmingham, VH 113, Box 600, 1670 University Boulevard, Birmingham, AL 35294, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Mao
authors.initials: M
authors.lastname: Li
authors.forename: Wenyao
authors.initials: W
authors.lastname: Lin
authors.forename: Wenquan
authors.initials: W
authors.lastname: Wang
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Rayburn
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.forename: Deng
authors.initials: D
authors.lastname: Chen
authors.forename: Xinsen
authors.initials: X
authors.lastname: Yue
authors.forename: Fuming
authors.initials: F
authors.lastname: Shen
authors.forename: Feng
authors.initials: F
authors.lastname: Jiang
authors.forename: Jie
authors.initials: J
authors.lastname: He
authors.forename: Wu
authors.initials: W
authors.lastname: Wei
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Zeng
authors.forename: Ruiwen
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000097:blood; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000097:blood*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000201:enzymology* / Q000453:epidemiology; D011237:Predictive Value of Tests
chemical_list: D014408:Biomarkers, Tumor; D017868:Cyclic AMP-Dependent Protein Kinases