Kemik O, Kemik AS, Sumer A, Begenik H, Purisa S, Tuzun S, Kotan C. Relationship between Clinicopathologic Variables and Serum and Tissue Levels of Dickkopf-1 in Patients with Rectal Cancer. Journal of Investigative Medicine. 2011 Aug;59(6):947–50. doi: 10.2310/jim.0b013e318224d8e4.