KRAS and neoplasm: Tumor DNA (mutated k-ras sequences) was found in three of the plasma samples from animals in group 1 (3/16), in one in group 3 (1/13), in three in group 5 (3/15), in eight in group 7 (8/16), in nine in group 9 (9/16), and in six in group 11 (6/14; Figure 3).