Background: Cystatin C is found to be down regulated in prostate cancer and modifies invasion of prostate
cancer cells via MAPK/Erk and androgen receptor pathways. In this work, we detected the frequency of cystatin
C gene single nucleotide polymorphism different variants and its relation to the serum levels of both total
testosterone and PSA.
Methods: The study was conducted on (50) cases of newly diagnosed Prostatic cancer patients and another age
and sex-comparable (50) healthy individuals as a control group. All were investigated for the frequency of
Cystatin C gene polymorphism, serum total testosterone and serum PSA.
Results: Cystatin C gene (BB) variant was detected in 16.0% of cases and 4.0% in controls which showed
significant difference with p value=0.046 as compared with (AA) and (AB) variants where (AA) variant was
detected in 56.0% of cases and 64.0% in controls which showed no significant difference with p value =0.414,
and (AB) variant was detected in 28.0% of cases and 32.0% in controls which also showed no significant
difference with p value = 0.663. The serum PSA levels in cases were from 30 to 150 (ng/ml) and in controls
were from 0.0 to 3.4 (ng/ml) which showed high significant difference between both groups with p value =
0.000. Serum PSA Levels was higher in the mutant type (BB) than the wild type (AA). As in wild type (AA) the
serum PSA levels ranged from 31.5 to 150 (ng/ml) and mutant type (BB) the serum PSA levels ranged from 65to 149.3 (ng/ml). Serum total testosterone levels in cases ranged from 2 to 7 (ng/ml) and in controls ranged from
2 to 7 (ng/ml) which showed no significant difference with p value = 0.574.
Conclusions: Cystatin C gene polymorphism particularly allelic variant B (CST3 BB) mutant type was
significantly associated with the susceptibility to prostate cancer. (CST3 BB) mutant type and PSA were
associated with the susceptibility to prostate cancer, but testosterone was not associated.