A man’s height is a modest marker for risk of prostate cancer development, but is more strongly linked to progression of the cancer, say British researchers who conducted their own study on the connection and also reviewed 58 published studies.In the September issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, 12 researchers at four universities in England studied more than 9,000 men with and without prostate cancer and estimated that the risk of developing the disease rises by about six percent for every 10 centimeters (3.9 inches) in height a man is over the shortest group of men in the study. That means a man who is one foot taller than the shortest person in the study would have a 19 percent increased risk of developing the disease.

Still, these increases in risk are a lot less than those linked with other established risk factors, such as age, family history of the disease, and race. Because of that, the researchers do not suggest that taller men be screened more often than is typical, or that their cancer treatment be altered.

“Compared to other risk factors, the magnitude of the additional risk of being taller is small, and we do not believe that it should interfere with preventive or clinical decisions in managing prostate cancer,” said the study’s lead author, Luisa Zuccolo, M.Sc., of the Department of Social Medicine at the University of Bristol. “But the insight arising from this research is of great scientific interest. Little is known on the causes of prostate cancer and this association with height has opened up a new line of scientific inquiry.”

For example, Zuccolo says that factors associated with height - not height itself – could be risk factors for progression to fatal prostate cancer, and a plausible mechanism behind this association could be the insulin-like growth factor-1(IGF-1) system, which stimulates cell growth and has been shown to be involved in prostate cancer incidence and progression.

Because some studies have shown a much greater association between height and prostate cancer risk – some between 20 to 40 percent – the researchers then placed their results in the context of available evidence. They conducted a meta-analysis of 58 studies, and found evidence that greater stature is associated with increased prostate cancer risk. But as in their study, the overall effect varied with study design and was modest – a three to 9 percent increase risk of development per 10 centimeters, and five to 19 percent increase in risk for more advanced cancer.

“We do not believe that height itself matters in determining risk of prostate cancer or prostate cancer progression, but we speculate that factors that influence height may also influence cancer and height is therefore acting as a marker for the causal factors,” Zuccolo said.

Genetic changes during the initiation and progression of prostate cancer have eluded scientists to date. Now for the first time researchers have identified a specific gene expression profile of prostate cancer stem cells, with important implications for future treatments. The findings, published in BioMed Central’s open access journal Genome Biology, revealed 581 genes that are differentially expressed in certain prostate cancer cells, highlighting several pathways important in the cancer stem-cells biology, and offering targets for new chemopreventative and chemotherapeutic approaches.

The cells in the study represent less than 0.1% of prostate cancer tumors, and have properties that mark them out as cancer stem cells. The cells renew themselves, are highly invasive, and have a longer lifetime than normal stem cells. They also feature a primitive epithelial phenotype and can differentiate to recapitulate phenotypes seen in prostate tumors. The cells are found in all stages and types of prostate cancer.

Expression profiling of prostate cancers typically uses tumor cell mass samples to identify individual genes. In this study, researchers harnessed advances in microarray and target labelling technologies to produce a functionally annotated expression profile of these prostate cancer stem cells.

The team, from the YCR Cancer Research Unit at the University of York and Pro-cure Therapeutics Ltd, created a malignant stem cell signature by combining genes significantly overexpressed in stem cells with those significantly overexpressed in malignant stem cells. Quantitative RT-PCR, flow cytometry and immunocytochemistry were used to validate the gene expression changes.

Genes associated with inflammation were prominent in the cancer stem cell expression profile. Potential therapeutic target NFκB is known to promote cell survival. The researchers showed that an NFκB inhibitor triggered programmed cell death in cancer stem cells, but spared normal stem cells. This provides a potential therapeutic target for this rare group of cells, which are unlikely to be affected by current chemotherapy regimens.

“For the first time we are looking at the subpopulation of cancer cells which actually initiate new tumors” explains Anne Collins, who coordinated the study. “The genetic profiling we have carried out should stimulate new lines of research directed towards stem cell treatments for cancer”

New research suggests that the form of tomato product one eats could be the key to unlocking its prostate cancer-fighting potential, according to a report in the June 1 issue of Cancer Research, a journal of the American Association for Cancer Research.“Processing of many edible plants through heating, grinding, mixing or drying dramatically increases their nutrition value, including their cancer prevention potential. It appears that the greatest protective effect from tomatoes comes by rehydrating tomato powder into tomato paste,” said Valeri V. Mossine, Ph.D., research assistant professor of biochemistry at the University of Missouri.

The protective effect of tomato products against prostate cancer has been suggested in many studies, but researchers remain uncertain about the exact mechanisms. Mossine and colleagues demonstrated that FruHis, an organic carbohydrate present in dehydrated tomato products, exerts a strong protective effect.

Researchers divided rats into groups of 20 and fed them a control diet or a diet that included tomato paste, tomato powder or tomato paste plus additional FruHis. All animals were then injected with prostate cancer-causing chemicals.

Animals fed the tomato paste plus FruHis diet had the longest survival from cancer at 51 weeks compared with 50 weeks in the tomato powder group, 45 weeks in the tomato paste alone group and 40 weeks in the control group.

On post-mortem exam, prostate tumors were found in 10 percent of the rats that had been given a combination of tomato paste and FruHis, compared with 30 percent of animals in the tomato powder group, 25 percent in the tomato paste alone group and 60 percent in the control group.

Mossine said the protective effect of tomato-based products was restricted to prostate tumors, which is consistent with other research on tomatoes and cancer. Incidence of other tumors was too small to examine.

In vitro, Mossine and colleagues evaluated the anti-cancer properties of FruHis and 14 other D-fructose amino acids and found that FruHis in a concentrated form protected against DNA damage known to lead to prostate cancer. When combined with lycopene, FruHis stopped cancerous cell growth more than 98 percent of the time.

“Before this study, researchers attributed the protective effect of tomatoes to ascorbic acid, carotenoids, or phenolic compounds,” Mossine said. “FruHis may represent a novel type of potential dietary antioxidant. Experiments like these suggest that a combination of FruHis and lycopene should be investigated as a potential therapeutic anti-tumor agent, not just a prevention strategy.”

Although Mossine cautioned against drawing broad conclusions from this animal study, he said, “the result may introduce an additional intrigue into an ongoing dispute over the beneficial effects of dietary lycopene and tomato products in lowering the risk of prostate cancer. Human trials are certainly warranted.”