NRAS and neoplasm: Interestingly, 10 of the 13 Wnt1-LateEx tumors profiled contained either codon 12 (1 tumor)- or codon 61 (9 tumors)-activating Hras1 mutations, whereas none of the Wnt1-EarlyEx tumors was mutated (Fisher's exact test P-value=0.0004) (Table 1).