In studies conducted with humans, Guess et al. [163] evaluated the effect of modified citrus pectin (Pecta-Sol® (Santa Rosa, CA, USA) in patients with prostate cancer showing that modified citrus pectin (MPC) can increase prostate-specific antigen (PSA) doubling time in 7 of 10 men (with biochemical recurrence of prostate cancer following local therapy) after taking MCP for 12 months, compared with before the take of MCP. This evidence concerns the gene KLK3 and prostate cancer.