BRCA2 and gastric cancer: The two most frequently mutated DDR genes in gastric cancer, ATM and BRCA2, with overall mutation prevalence of 9.6% and 8.7%, respectively, in the gastric cohort of TCGA, were mutated in 10.1% and 7.6% of higher CDX2-expressing cancers and in 9.7% and 8.1% of CDX2-lower-expressing cancers (Fisher’s exact test p = 1 for both comparisons, Table 3).