SMAD3 and lung cancer: Previously, a Tribble family member TRIB3 was reported to interact with Smad3.18 TRIB2, another Tribble family member, acts as an oncogene in acute myeloid and T-cell acute lymphoblastic leukemias19 and some lung cancers,20, 21 but whether TRIB2 and Smad3 interact is unclear.