Chromogranin A expression linked to prostate cancer biochemical failure
MedWire News: Chromogranin A (CHGA) polymorphisms and expression and endothelin-1 expression are both linked to prostate cancer risk, with expression of chromogranin A also predicting biochemical failure, say Japanese researchers.
Previous studies have indicated that CHGA expression is associated with prostate cancer and plasma endothelin-1 levels are increased in advanced prostate cancer. However, the link between CHGA polymorphisms and prostate cancer is unclear and the associations between CHGA and endothelin-1 have not been investigated.
Norihiko Tsuchiya, from Akita University School of Medicine, and colleagues therefore used polymerase chain reaction-restriction fragment length polymorphism testing to determine the presence of two CHGA polymorphisms in DNA samples from 435 prostate cancer patients and 316 age-matched male healthy controls.
In addition, CHGA and endothelin-1 expression was assessed using immunohistochemistry (IHC) in prostate specimens from 114 prostate cancer patients who underwent radical retropubic prostatectomy and 27 bladder cancer patients who had radical cystectomy.
The team reports in the Journal of Urology that there was no significant association between the rs9658635 polymorphism of CHGA and prostate cancer risk. In contrast, the GG and GC genotypes of the Glu264Asp CHGA polymorphism were linked to a significantly increased risk for prostate cancer compared with the CC genotype, at odds ratios of 2.05 and 1.97, respectively. Neither of the polymorphisms were associated with clinical stage or Gleason score.
CHGA grade on IHC was significantly associated with Gleason score and increased clinical stage. Furthermore, CHGA IHC grade was an independent predictor of possible biochemical failure following radical retropubic prostatectomy. While endothelin-1 grade on IHC was significantly associated with a higher Gleason score, there was no association with clinical stage or the risk for biochemical failure.
The researchers also note that CHGA polymorphisms were not significantly associated and there was no association between CHGA and endothelin-1 expression.
They conclude: "A CHGA genetic variant may modify prostate cancer carcinogenesis and CHGA expression may be a useful biomarker to predict the higher malignant potential of localized prostate cancer and biochemical failure after radical retropubic prostatectomy.
"Thus, results suggest that CHGA is involved in prostate cancer carcinogenesis and progression."
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By Liam Davenport