The following gene polymorphisms known to be associated with neuropsychiatric disorders were investigated:
A. The STin2 VNTR in the serotonin transporter SLC6A4 gene;
B. The 30-bp VNTR in the monoamine oxidase A MAOA gene;
C. The Val158Met polymorphism in the catechol-ortho-methyltransferase COMT gene;
D. The promoter region C-521T polymorphism and the 48 VNTR in the third exon of the dopamine receptor DRD4 gene.
The STin2 12R/10R variant of the SLC6A4 gene and the -521T/T homozygosity of the DRD4 gene tended to be overrepresented in PC patients with unfavorable disease prognosis.
These gene variants are regarded as protective against schizophrenia, and the observed trend may be directly related to a reduced PC risk described for schizophrenia patients.
Oncotarget published "The presence of polymorphisms in genes controlling neurotransmitter metabolism and disease prognosis in patients with prostate cancer: a possible link with schizophrenia" reported that polymorphisms of neurotransmitter metabolism genes were studied in patients with prostate cancer (PC) characterized by either reduced or extended serum prostate-specific antigen doubling time corresponding to unfavorable and favorable disease prognosis respectively.