Levy et al [20] used a tetracycline-inducible small interfering RNA approach to inhibit SMAD4 function in PDAC cell line Colo-357 and demonstrated that loss of SMAD4 indeed promoted TGF-β mediated tumorigenesis through abolishing tumor-suppressive functions of TGF-β/SMAD4. Here, SMAD4 is linked to neoplasm.