SMARCA4 and adenocarcinoma: Moreover, while missense mutations can severely alter a protein's function, the rate of missense mutations in BRG1 was < 4% and < 6% for squamous cell and adenocarcinoma subtypes of NSCLC, respectively, according to the Atlas and COSMIC databases; these values are much lower than the observed rate of BRG1 loss of expression by IHC.