of steroid hormones, antigens Enzyme activity (ODC/polyamines) Growth factor receptors (EGFR superfamily: c-erb-2) Growth factors (TGFs, IGFs) Nuclear receptors (AR, ER, RAR/RXR, PPAR) Infectious HPV 16/18 Helicobacter pylori Radiologic imaging Mammographic parenchymal patterns (breast density, microcalcifications) ODC, ornithine decarboxylase; EGFR, epidermal growth factor receptor; TGF, transforming growth factor; RXR, retinoid X receptor; PPAR,
perisome proliferative activated receptor; HPV, human papilloma virus.