The Tuesday news reports: January 13, 2008


In addition to the comentary on outcomes of radical prostatectomy in men of 70 years and older, there are four reports in today’s news, addressing:

  • Garlic as a dietary component that prevents cancer
  • How “knock down” of androgen receptor expression and PCPH expression may potentially impact prostate cancer treatment
  • The clinical impact of discordant post-biopsy and post-Gleason scores on outcomes in men being treated with surgery.

Kim and Kwon have published a meta-analysis of 19 published, scientifically sound studies that looked at garlic intake and risk reduction for specific cancers. Based on this analysis, they concluded that there was no credible evidence to link garlic intake with a reduced risk for gastric, breast, lung, and endometrial cancers. They found very limited, but credible, evidence linking garlic intake to a reduced risk for colon, prostate, esophageal, laryngeal, oral, ovarian, and renal cell cancers. According to Colleen Doyle, director of nutrition and physical activity for the American Cancer Society, “The bottom line is, there is certainly not enough evidence for garlic for a health claim for any cancer prevention.” Doyle added, “If you like garlic, great. Roast it, chop it up, sauté it. It’s not going to be harmful to you. … If, down the line, stronger evidence emerges that garlic has an impact on cancer, great. If you like it, eat it.”

Snoek et al. have hypothesized that “knocking down” androgen receptor expression will have a major effect on inhibiting growth of castration-resistant prostate cancer tumors. The term “knock down” is usually associated with a technique used to eliminate (“knock out”) expression of a specific gene but which fails to knock out expression completely. The authors describe a process by which they were able to “knock down” expression of androgen receptor messenger RNA and protein, leading to decreased expression of PSA, reduced activation of the PSA-luciferase reporter, and growth inhibition of C4-2 cells. When this process was tested in mice, serum PSA decreased, and in half of them, there was complete tumor regression and disappearance of serum PSA. This study offers the first direct evidence that “knock down” of androgen receptor expression may offer a viable strategy for treatment of prostate tumors that have progressed to the castration-resistant state.

In another “knock down”-related study, Villar et al. have identified the PCPH protein and mitochondrial PCPH as important participants in the response of prostate cancer cells to certain types of chemotherapy, established a role for functional interactions of PCPH, protein kinase Cα (PKCα), and Bcl-2 in the drug response process, and implied that targeting PCPH expression before, or simultaneously with, chemotherapy may improve the treatment outcome for prostate cancer patients.

Serkin et al. have tried to quantify the impact of a discordant Gleason score (GS) between the value available based on the prostate biopsy tissue and that based on the post-surgical  specimen among men initially diagnosed with Gleason 6 or 7 prostate adenocarcinoma and treated with radical prostatectomy. Their study demonstrated that, among patients with GS 6 on biopsy, 681/1,847 patients (36.86 percent) were upgraded to GS 7 or higher after surgery. Surgical margin, capsular involvement, seminal vesicle, and nodal involvement status were more favorable in patients with concordant biopsy and surgical specimens with GS 6 (P < 0.0001). Patients with smaller prostates were also found to have higher PSA densities and were more likely to be upgraded following surgery. The authors argue the discordance evident in their study has potential clinical significance in predicting oncologic outcomes.

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