Studies examining the effect of a soy protein diet on the menstrual cycle have demonstrated a significant increase in follicular phase length and delay in menstruation, including suppression of midcycle surges of LH and FSH, which potentially may reduce the risk of breast cancer (Cassidy et al, 1994; Lu et al, 1996; Nagata et al, 1998; Kumar et al, 2002). This evidence concerns the gene PLOD1 and breast cancer.