Kohei Kurokawa

Genistein, a soy isoflavone, induces glutathione peroxidase in the human prostate cancer cell lines LNCaP and PC-3.

Genistein is a major component of soybean isoflavone and has multiple functions resulting in antitumor effects. Prostate cancer is 1 of the targets for the preventive role of genistein. We examined the effect of genistein on human prostate cancer (LNCaP and PC‐3) cells. Proliferation of both cell lines was inhibited by genistein treatment in a dose‐dependent manner. To obtain the gene expression profile of genistein in LNCaP cells, we performed cDNA microarray analysis. The expression of many genes, including apoptosis inhibitor (survivin), DNA topoisomerase II, cell division cycle 6 (CDC6) and mitogen‐activated protein kinase 6 (MAPK 6), was downregulated. Expression levels were increased more than 2‐fold in only 4 genes. The glutathione peroxidase (GPx)‐1 gene expression level was the most upregulated. Quantitative real‐time polymerase chain reaction revealed significant elevation of transcript levels of GPx‐1 in both LNCaP and PC‐3 cells. Upregulation of gene expression levels accompanied elevation of GPx enzyme activities. In contrast, no significant changes were observed in the gene expression levels and enzyme activities of the other antioxidant enzymes, superoxide dismutase and catalase. GPx activation might be one of the important characteristics of the effects of genistein on prostate cancer cells.

NK cell-mediated anti-tumor immune response to human prostate cancer cell, PC-3: immunogene therapy using a highly secretable form of interleukin-15 gene transfer

Interleukin (IL)‐15 is a pleiotropic cytokine that is important forinnate and adaptive immune cell homeostasis. The expression of IL‐15protein is controlled by posttranscriptional mechanisms. Here, weconstructed a human IL‐15 expression vector consisting of the humanIL‐2 signal peptide, the human IL‐15 mature peptide‐coding sequences,and an out‐of‐frame human growth hormone gene. Human prostate cancercells, PC‐3, transfected with this highly secretable form of the IL‐15gene, successfully secreted abundant bioactive IL‐15 protein. In nudemice, the growth of PC‐3 cells producing IL‐15 was remarkably retarded.NK cell‐depletion using anti‐asialo GM1 antibody restoredtumorigenicity. Histologically, tumors derived from IL‐15‐producingPC‐3 cells contained necrotic areas with high apoptotic index.Splenocytes incubated with supernatant of transfectants killed targetPC‐3 cells and expressed a significantly high level of mIFN‐γ mRNA.These observations suggest that NK cell‐mediated, anti‐tumor effects ofIL‐15 could provide a potential rationale for gene therapy of prostatecancer.

A p53 codon 72 polymorphism associated with prostate cancer development and progression in Japanese

An association between the Pro/Pro genotype of p53 codon 72 and a lower risk of prostate cancer in Caucasians was recently reported. However, the association of this polymorphism with prostate cancer risk in a Japanese population has not been clarified. We performed a case-control study consisting of 114 prostate cancer patients and 105 noncancer controls. Sixty-nine percent (79 of 114) of the patients had a positive family history. The genotypic frequencies in the controls were 39.0% for Arg/Arg, 54.3% for Arg/Pro and 6.7% for Pro/Pro; they were in Hardy-Weinberg equilibrium. When a comparison of the distribution of the p53 codon 72 polymorphism was made between patients with a first-degree family history and all control subjects, the adjusted odds ratios (ORs) for prostate cancer associated with the Arg/Arg, Arg/Pro and Pro/Pro genotypes were 1.00, 0.99 [95% confidence interval (CI) 0.53-1.88] and 2.80 (95% CI 1.04-7.53), respectively. When stratification of cases was performed based on clinical stage (localized or metastatic cancer) and pathological grade (a Gleason score of <7 or > or =7), there tended to be a greater number of patients with localized cancers among those patients with the Arg/Pro genotype than among those with the Arg/Arg genotype (overall cases: age-adjusted OR 0.36, 95% CI 0.13-1.00, p = 0.049; positive family history cases: age-adjusted OR 0.25, 95% CI 0.075-0.84, p = 0.025). In addition, there tended to be a greater number of patients with low-grade cancers among those with the Pro/Pro genotype than among those with other genotypes (overall cases: age-adjusted OR 0.41, 95% CI 0.13-1.30, p = 0.13; positive family history cases: age-adjusted OR 0.20, 95% CI 0.004-0.89, p = 0.035). The present findings suggest that the Pro/Pro genotype of p53 codon 72 played a role in prostate cancer susceptibility in a Japanese population. However, the Pro allele did not appear to worsen such clinical parameters as clinical stage or pathological grade.

Vitamin D receptor gene polymorphism in familial prostate cancer in a Japanese population

Aim: Vitamin D acts as an antiproliferative agent against prostate cells. Epidemiological study has shown that a low level of serum vitamin D concentration is a risk factor for prostate cancer. Vitamin D acts via vitamin D receptor (VDR), and an association of genetic polymorphisms of the VDR gene has been reported. In the current study, we examined the association of VDR gene polymorphisms with familial prostate cancer in a Japanese population.

Diagnostic significance of digital rectal examination and transrectal ultrasonography in men with prostate-specific antigen levels of 4 NG/ML or less.

OBJECTIVES To investigate the usefulness of digital rectal examination (DRE) and transrectal ultrasonography (TRUS) for prostate cancer diagnosis and to propose a diagnostic algorithm for individual-based cancer screening in subjects with prostate-specific antigen (PSA) levels of 4.0 ng/mL or less. METHODS Between January 1992 and March 2000, 129 subjects with PSA levels of 4.0 or less and abnormal findings on DRE or TRUS underwent prostate biopsy. The subjects were divided into four groups according to the PSA range: 0 to 0.9 ng/mL, 1.0 to 1.9 ng/mL, 2.0 to 2.9 ng/mL, and 3.0 to 4.0 ng/mL. The reliability of the DRE and TRUS and the clinicopathologic features of prostate cancer were investigated among these four groups. RESULTS Of the 129 subjects, 17 (13.2%) patients with prostate cancer were diagnosed. The detection rate was 2.2% (1 of 45), 0% (0 of 27), 20.6% (7 of 34), and 39.1% (9 of 23) in subjects with PSA levels of less than 1.0 ng/mL, 1.0 to 1.9 ng/mL, 2.0 to 2.9 ng/mL, and 3.0 to 4.0 ng/mL, respectively. The proportion of patients with Stage II, III, and IV was 58.8%, 41.2%, and 0%, respectively. The percentage with Gleason scores of 8 to 10 was 17.6%. The detection rate of abnormal findings on DRE and TRUS was 14.4% (13 of 90) and 9.5% (7 of 74), respectively. Adding TRUS to DRE in the screening program of subjects with PSA levels of 2.0 to 4.0 ng/mL, increased the detection rate of prostate cancer to 30.8% (4 of 13). CONCLUSIONS Routine prostate biopsy should not be undertaken except for highly suspicious DRE findings in subjects with PSA levels less than 2.0 ng/mL. The additional use of TRUS in subjects with PSA levels of 2.0 to 4.0 ng/mL would improve the sensitivity of prostate cancer detection. The diagnostic algorithm proposed in the present study is useful as a screening method for prostate cancer in subjects with PSA levels of 4.0 ng/mL or less.

Endocrine Environment of Benign Prostatic Hyperplasia: Prostate Size and Volume are Correlated with Serum Estrogen Concentration

Estrogen plays an important role in the development of benign prostatic hyperplasia (BPH), as has been shown in both experimental and clinical studies. T determine the endocrine environment of BPH, serum total testosterone (Total-T), free testosterone (Free-T), and estradiol (E2) conceptions were measured, and the relationship between these levels and prostate size and volume was analyzed. Blood samples were collected from subjects who attended the mass screening for prostate disease performed by our institute. No significant correlations were found between Total-T levels, Free-T levels, and prostate size, as determined by digital rectal examination. However, E2 levels and the ratios for E2 levels and the ratios for E2/Total-T and E2/Free-T were significantly correlated with prostate size. To confirm these relationships, prostate volume was calculated from transrectal ultrasonographic images. E2 levels and these two ratios were, indeed, highly correlated with prostate volume. These results suggest that an estrogen-dominant environment plays an important role in the development of BPH.

A Comparison of Interobserver Reproducibility of Gleason Grading of Prostatic Carcinoma in Japan and the United States

CONTEXT Gleason grading is now the sole prostatic carcinoma grading system recommended by the World Health Organization. It is imperative that there be good interobserver reproducibility within this system worldwide. To our knowledge, there are no studies, using the same specimens, that compare the interobserver reproducibility of Gleason grading in Japan and the United States. OBJECTIVE To compare the interobserver reproducibility of Gleason grading of prostatic carcinoma in Japan and the United States using, in Japan, images from the identical biopsy glass slides that were originally graded in the United States. DESIGN Microsopic images from 37 needle biopsies of prostatic carcinoma were placed on CD-ROM and distributed to 14 Japanese pathologists for grading. These 14 physicians included 8 general pathologists and 6 pathologists with a special interest in urologic pathology. The needle biopsies had been previously reviewed so that a consensus diagnosis could be formed by a panel of urologic pathologists in the United States and Canada. Interobserver agreement with the consensus diagnoses was calculated by determining the overall kappa coefficient for the Japanese pathologists and then compared to the interobserver agreement among American general pathologists who had previously graded identical needle biopsies from which the CD-ROM images had been taken. RESULTS The interobserver agreement with the consensus diagnoses for the 4 Gleason grading groups (Gleason grades 2-4, 5-6, 7, and 8-10) among the Japanese urologic pathologists in this series of cases was substantial (overall kappa = 0.68), and for the Japanese general pathologists, it was moderate (overall kappa = 0.49), similar to that reported in the earlier study of American general pathologists (overall kappa = 0.44). The major interobserver reproducibility problem for both Japanese and American general pathologists is undergrading. The major areas of undergrading are the underdiagnosis of Gleason scores 5-6 as Gleason scores 2-4, and the underdiagnosis of cribriform sheets and fragments of cribriform Gleason pattern 4 carcinoma as Gleason pattern 3. CONCLUSIONS The interobserver reproducibility of the Gleason grading for this collection of specimens was similar among Japanese and American general pathologists. The overall kappa values for these generalists of 0.44 and 0.49 are only in the moderate (0.41-0.60) range of interobserver agreement when compared to 0.68, substantial (0.61-0.80) agreement, for Japanese urologic pathologists. Educational efforts to improve Gleason grading have been shown to be effective and are clearly warranted.

Usefulness of age-specific reference range of prostate-specific antigen for japanese men older than 60 years in mass screening for prostate cancer

OBJECTIVES To investigate the age-specific reference range of prostate-specific antigen (PSA) in Japanese men older than 60 years of age by analyzing the receiver operating characteristic (ROC) curve. Several reports have noted that many clinically serious cancers are missed by raising the cutoff value of the age-specific PSA reference range for men older than 60 years. METHODS We studied 6744 individuals who had undergone mass screening for prostate cancer in Gunma Prefecture from 1994 to 1998. PSA determination was the first step of the mass screening in all subjects. Digital rectal examination and transrectal ultrasonography (TRUS) were performed in all except in a fraction of patients. Subjects with an abnormal PSA level or abnormal digital rectal examination or TRUS findings underwent TRUS-guided systematic sextant biopsies. Patients older than 60 years of age were grouped according to their age at 5-year intervals, and the cutoff value of the age-specific PSA reference range was calculated for each age group by analyzing the ROC curve. RESULTS The diagnostic efficiency of the age-specific PSA reference range was optimal with cutoff values of 3.0, 3.5, 4.0, 4.0, and 7.0 ng/mL in subjects 60 to 64, 65 to 69, 70 to 74, 75 to 79, and older than 80 years of age, respectively. By using the age-specific PSA reference range as determined by the ROC curve, the sensitivity, specificity, and efficiency increased to 92.4%, 91.2%, and 84.3%, respectively. When the standard PSA reference range was used for the diagnosis, the sensitivity, specificity, and efficiency was 89.1%, 92.4%, and 82.3%, respectively. All of the cases of prostate cancer detected by using the age-specific PSA reference range with the cutoff point based on the ROC curves were clinically significant. CONCLUSIONS The age-specific PSA reference range cutoff value in this setting demonstrated better diagnostic efficiency than the standard cutoff value of PSA and the age-specific PSA reference range determined by the 95% confidence interval. It appears likely to be a useful diagnostic index for the first step of mass screening in Japanese men.

The diagnostic accuracy of the age-adjusted and prostate volume-adjusted biopsy method in males with prostate specific antigen levels of 4.1-10.0 ng/mL.

The authors evaluated a new age‐adjusted and prostate volume‐adjusted biopsy method for the detection of prostate carcinoma through the transperineal and the transrectal approaches in men with PSA levels of 4.1–10.0 ng/mL.

Correlation of prostate-specific antigen before prostate cancer detection and clinicopathologic features : Evaluation of mass screening populations

OBJECTIVES Although prostate-specific antigen (PSA) has become the reference standard for prostate cancer diagnosis, few reports have examined the long-term changes in PSA values before the diagnosis of prostate cancer in a large number of subjects. We investigated serial PSA levels and related values before prostate cancer diagnosis in a mass screening population and analyzed the values in an attempt to discover some values useful in clinical diagnostic science. METHODS We performed mass screening for prostate cancer in 9671 subjects from 1986 to 1998. The initial screening method was measurement of prostatic acid phosphatase from 1986 to 1991 and measurement of PSA from 1992 to 1998. As a result, 303 cases of prostate cancer were diagnosed. For all the cases diagnosed before 1991, we measured the serum PSA value in preserved frozen serum. RESULTS The prostate cancer detection rate was 3.1% among all subjects observed during the 13-year period. By measurement of the PSA level using frozen serum during the pre-PSA era, we found that 62% of patients demonstrated a PSA abnormality for more than 1 year (average 2.8) before prostate cancer diagnosis. Prostate cancer that was diagnosed within 1 year after a PSA value became abnormal was not associated with bone metastasis. Concerning the relationship between PSA velocity (PSAV) and clinical stage, the proportion of Stage B cancer was 86% in the subjects whose PSAV level before diagnosis was 0.18 ng/mL/yr or less and it was only 29% in those with PSAV levels of 4.5 ng/mL/yr or more. Only 3 (3.5%) of 86 patients with prostate cancer with PSAV levels of 4.4 ng/mL/yr or less had bone metastasis, and 2 of those 3 patients had poorly differentiated adenocarcinoma. CONCLUSIONS Although a total of 62% of patients had an abnormal PSA level more than 1 year before prostate cancer diagnosis, no patients with prostate cancer who were diagnosed within 1 year after the PSA level became abnormal had bone metastasis. Among patients who have undergone mass screening twice or more, a clinically useful indicator of the lack of bone metastasis would be a period between the detection of PSA levels of 4.1 ng/mL or more but not more than 10 ng/mL and prostate cancer diagnosis of less than 1 year and a diagnosis of well or moderately differentiated adenocarcinoma or a PSAV of 4.4 ng/mL/yr or less and a cancer diagnosis of well or moderately differentiated adenocarcinoma.