BRCA1 and neoplasm: In a subsequent study, the same investigators demonstrated that transgenic mice homozygous for mutant Brca1 I26A targeted to specific tissues (e.g., pancreas or mammary gland) suppressed tumor formation to the same degree as wild-type Brca1; whereas a Brca1-mutation of the BRCT domain that abrogated phosphoprotein-binding (S1598F) conferred a high rate of tumor formation in the same genetic models (Shakya et al., 2011).