Prostate Cancer

German Cancer Research Center, Heidelberg, Germany.

To review and summarize evidence from longitudinal studies on the association between serum 25-hydroxyvitamin D (25(OH)D) and the risk of prostate cancer (PC).

Relevant prospective cohort studies and nested case-control studies published until July 2009 were identified by systematically searching Ovid Medline, EMBASE, and ISI Web of Knowledge databases and by cross-referencing. The following data were extracted in a standardized manner from eligible studies: first author, publication year, country, study design, characteristics of the study population, duration of follow-up, PC incidence/PC mortality according to serum vitamin D status and the respective risk ratios, and covariates adjusted for in the analysis. Due to the heterogeneity of studies in categorizing serum vitamin D levels, all results were recalculated for an increase in serum 25(OH)D by 10ng/ml. Summary odds ratios (ORs) were calculated using meta-analysis methods.

Overall, eleven original articles were included, ten of which reported on the association between serum vitamin D levels and PC incidence and one article reported on the association with PC mortality. Meta-analysis of studies on PC incidence resulted in a summary OR (95% confidence interval, CI) of 1.03 (0.96-1.11) associated with an increase of 25(OH)D by 10ng/ml (P=0.362). No indication for heterogeneity and publication bias was found.

According to available evidence from longitudinal studies, serum 25(OH)D is not associated with PC incidence.


UroToday.com Prostate Cancer Section

Inhibiting TNF-receptor associated protein-1 (TRAP-1) may prevent cancer cell death, according to investigators at the University of Massachusetts Medical School. They also note that TRAP-1 is a marker of localized and metastatic prostate cancer and is required for prostate cancer cell viability.

The report will appear in the January 2010 issue of the American Journal of Pathology in a paper titled “Cytoprotective Mitochondrial Chaperone TRAP-1 as a Novel Molecular Target in Localized and Metastatic Prostate Cancer.”

Since TRAP-1 is known to regulate cell death, the researchers decided to study its role in prostate cancer. They found that the protein was highly expressed in both high-grade human prostate cancer lesions and mouse models of prostate cancer but not in benign or normal prostate tissue.

In addition, TRAP-1 overexpression in noncancer prostate cells inhibited cell death, whereas TRAP-1-deficient prostate cancer cells had enhanced levels of cell death. Moreover, treatment with gamitrinibs, a class of small molecules that inhibit TRAP-1, resulted in prostate cancer cell death but not death of noncancerous prostate cells.

Dario C. Altieri, M.D., who led this research, reported in February on the synthesis and properties of gamitrinib as a treatment for prostate cancer in The Journal of Clinical Investigation. He designed gamitrinibs to selectively target Hsp90 in human tumor mitochondria. TRAP-1 is a mitochondria-localized Hsp90 chaperone. Therefore, Dr. Altieri believes that based on his research, targeting TRAP-1 via gamitrinib may be a viable therapeutic strategy for patients with advanced prostate cancer.

Dr. Altieri’s experiments also found that TRAP-1 was differentially expressed in localized and metastatic prostate cancer compared with normal prostate.

A similar approach may be also suitable for other types of cancer, as TRAP-1 is broadly expressed in disparate human malignancies, Dr. Altieri continues. He plans to “further dissect the biology of TRAP-1 cytoprotection in cancer cells and test whether disabling its function may overcome drug resistance, the most common reason of treatment failure and dismal outcome in patients with advanced prostate cancer.”

GEN News Highlights

Moderate amounts of regular exercise may lower mortality rates for prostate cancer survivors, according to a study presented at the American Association for Cancer Research Frontiers in Cancer Prevention Research Conference.

The study's authors explained that previous investigations focused on how exercise affected the risk of developing prostate cancer but failed to identify the exact molecular effects that exercise had on prostate cancer.

To examine exercise in relation to overall survival rates in prostate cancer survivors, lead author, Stacey Kenfield, ScD, epidemiology research associate at the Harvard School of Public Health, and colleagues assessed physical activity levels for 2686 males with prostate cancer before and after diagnosis.

Researchers found that men who engaged in 3 or more hours of Metabolic Equivalent Tasks (MET) a week—equivalent to jogging, biking, swimming, or playing tennis for about a half-hour per week—had a 35% lower risk of overall mortality. Furthermore, men who walked ≥90 minutes at a normal to brisk pace had a 51% lower risk of all-cause mortality compared to men who walked <90 minutes at an easy walking pace.

“We saw benefits at very attainable levels of activity,” said Kenfield. “Our data indicate that for prostate cancer survivors, a moderate amount of regular exercise may improve overall survival, while ≥5 hours per week of vigorous exercise may decrease the death rate due to prostate cancer specifically.”

http://www.ajho.com

AFP - WASHINGTON — US researchers have found an antibody that hunts down prostate cancer cells in mice and can destroy the killer disease even in an advanced stage, a study showed Monday.

The antibody, called F77, was found to bond more readily with cancerous prostate tissues and cells than with benign tissue and cells, and to promote the death of cancerous tissue, said the study published in the Proceedings of the National Academy of Science (PNAS).

When injected in mice, F77 bonded with tissue where prostate cancer was the primary cancer in almost all cases (97 percent) and in tissue cores where the cancer had metastasized around 85 percent of the time.

It recognized even androgen-independent cancer cells, present when prostate cancer is incurable, the study by researchers at the University of Pennsylvania showed.

F77 "initiated direct cell death of prostate cancer cells... and effectively prevented tumor outgrowth," it said.

But it did not target normal tissue, or tumor tissues in other parts of the body including the colon, kidney, cervix, pancreas, lung, skin or bladder, the study showed.
he antibody "shows promising potential for diagnosis and treatment of prostate cancer, especially for androgen-independent metastatic prostate cancer," which often spreads to the bones and is difficult to treat, the researchers wrote in PNAS.

Currently, the five-year survival rate for metastatic prostate cancer is just 34 percent, according to the study.

Prostate cancer is the second most common cancer among men, claiming half a million lives each year worldwide, according to the World Health Organisation (WHO).

EducationGuardian.co.uk

Being diagnosed with prostate cancer may raise men's risk of having a heart attack or stroke, especially in the first week after diagnosis. Researchers found an increased risk of about 30 percent during the year after prostate cancer diagnosis. The risk of suicide during this time also increased, although this was much less common than heart problems.

What do we know already?
The numbers of men being diagnosed with prostate cancer are increasing, especially now that a blood test (called prostate-specific antigen, or PSA) that can help detect potential prostate cancer is more widely used. This may mean that more men are diagnosed early, and some may have a better chance of being treated and surviving their cancer.

However, we're not sure that all men with prostate cancer benefit from treatment. The research isn't clear. Part of the trouble is that many prostate cancers grow very slowly, and might never have caused any trouble if they'd not been picked up. Others grow much more quickly. It's hard to tell which cancers are likely to need treatment, and which are best left alone.

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