Patients

The study involved 118 men—34 with newly diagnosed and untreated PC and 84 without PC. Ninety-one percent of the men with PC (n=31) were African Americans, and 9% were Caucasians. In the non-PC (control) group, 61.9% (n=52) were African Americans, 35.7% (n=30) were Caucasians, and 2.38% (n=3) were other. The age ranges were 49-75 and 49-78 years for PC patients and controls, respectively. All men participated in an ongoing PC screening and early detection program at Louisiana State University Health Sciences Center in New Orleans. Recommendation for transrectal ultrasonography of the prostate was offered to those participants whose prostate-specific antigen (PSA) level was higher than 2.5 ng/mL for definitive histopathological diagnosis or had an abnormal digital rectal examination. All participants diagnosed with PC and included in the study were diagnosed and treated by the senior author (WR) between 1999 and 2001. PSA samples comprising the control group were chosen from a pool of approximately 6,000 participants based on the following criteria: a) PSA <2.5 ng/ml in whom the likelihood of having PC is very low (n=70); b) PSA level >2.5 ng/ml, with a negative biopsy for PC (n=10); c) men ages of 49-78 years, and d) no specific symptoms or complaints at the time of study entry. Since this was a retrospective study, no information had been collected on the dietary intake of iron or factors known to affect iron status, such as smoking, or recent blood loss or donation. The study and consent were approved by the Institutional Review Board of Louisiana State University Health Sciences Center, and informed consent was obtained from all participants prior to screening.

Laboratory Tests

Various measurements were made on previously frozen (-80°C) serum samples. PSA levels were measured by the Bayer Immuno 1TM assay (Bayer Corporation, Tarrytown, NY). Serum ferritin levels were measured by enzyme immunoassay with commercial kits purchased from RAMCO (Houston, TX). Serum iron and TIBC were measured by colorimetry with kits purchased from Sigma (St. Louis, MO). Test samples, standards, and controls were assayed in duplicate according to manufacturer’s recommendations. TS was calculated by dividing serum iron by TIBC. Elevated body iron stores were defined as serum ferritin above 300 |ug/L and TS >50%. Reduced body iron stores were defined as serum ferritin less than 12 (ig/L and TS <16%. In those men with inflammation (see below), the threshold for reduced body iron stores was defined as serum ferritin <100 |iig/L. To rule out the presence of an inflammatory process—a factor known to increase serum ferritin and reduce serum iron (hence, TS), we measured serum levels of alpha 1-acid glycoprotein (AGP), C-reactive protein (CRP), antichymotrypsin (ACT), and ceruloplasmin (Cp) by radial immunodiffusion. Polyclonal antibodies against the various acute phase proteins produced in rabbits, and standard and control serum samples were purchased from Dako Corporation (Carpinteria, CA). Inflammation was recorded as being present when the concentration of at least two of the four acute phase proteins were above the cut-off points suggested by Dako Corporation or those reported in the literature: AGP >1 g/L, CRP >10 mg/L, ACT >500 mg/L, and Cp >500 mg/L.
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Statistical Analysis

Descriptive statistics, analysis of variance (ANO-VA), and correlation coefficients were performed by a microstatistical program (Microsoft Inc., Indianapolis, IN) as described in the literature. Since serum ferritin levels are skewed, they were logarithmically transformed before ANOVA was performed. Antilogarithm serum ferritin levels were recalculated to determine geometric means. Serum ferritin andTS were also compared by ANOVA as a function of PC status and age (years: <51,51-55,56-60,61-70, and 71), and inflammation status as defined in the preceding paragraph. The 95% confidence intervals (CI) were calculated as follows: x± 1.96 x SEM, where x = the mean of the group, SEM = standard error of the mean, 1.96 a Z score that describes the location (standard deviation) of a particular value relative to the population mean. Details on the derivation and use of the formula are described in the literature. The level of significance was set at p<0.05. canadian cialis online

Category: Cancer / Tags: iron deficiency, iron overload, prostate cancer, serum ferritin, transferrin saturation

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