Not surprisingly, BRG1 may function as a tumor suppressor; BRG1 hemizygous mice are susceptible to tumors [10], while complete loss of BRG1 potentiates lung cancer development [11] and BRG1 is silenced or mutated in human tumor cell lines derived from breast, ovarian, lung, brain and colon cancers [4,12]. This evidence concerns the gene SMARCA4 and lung cancer.