The pro-tumor growth effect of BMP4 noted in 231-HM SMAD4-knockdown and 468-GIL SMAD4-null tumors was not observed in SMAD4-knockout 4T1.2 tumors (Fig. S4e), possibly due to differences in the tumor models and/or due to an active host immune response in the BALB/c mice [7]. The gene discussed is SMAD4; the disease is neoplasm.