ARID1A and thyroid gland undifferentiated (anaplastic) carcinoma: These findings are supported by the demonstration of loss of the ARID1A protein, BAF250a, by immunohistochemistry in 14% of gastric and anaplastic thyroid carcinomas [Wiegand et al., 2011] and by the identification of ARID1A point mutations in 3 of 48 pancreatic cancers by Birnbaum et al. [2011].