KRAS and adenocarcinoma: In the series by Giaretti et al. [6], intratumor KRAS heterogeneity was present in 3 of 9 mutated cases (33%) or 3 of a total of 19 adenocarcinomas (16%), by examining a multiple set of samples from both superficial and deep primary tumor sectors (from 6 to 11 per resection).