Broccoli & Signalling Pathways Figure 7. N-terminal modification of TGFb1 by SF. MS/MS spectra of m/z 768.7 representing the unmodified N-terminal peptide of TGFb1 at retention time 23.43 min (A) and m/z 877.2 representing a modified form of TGFb1 seen only in SF treated samples at retention time 30.85 minutes (B). Note that the y ion series remains the same while the b ion series shifts (D) indicating an N-terminal modification of mass 21760.8 Da. Figure S2 provides an explanation of the mass addition of 217, as opposed to 177. doi:10.1371/journal.pone.0002568.g007 In conclusion, we consider that our study has provided a mechanistic basis for the reduction in risk of prostate cancer through broccoli consumption, as suggested by epidemiological studies. Further studies with larger cohorts, combined with the assessment of clinical endpoints, are warranted. Supporting Information Table S1 Primers and probes for genotype analysis. Found at: doi:10.1371/journal.pone.0002568.s001 (0.05 DOC) MB PLoS ONE | www.plosone.org 12 July 2008 | Volume 3 | Issue 7 | e2568