Tissue surfaces ranged from 0.7 mm2 to 635.3 mm2 (mean surface area: 216.3 mm2 [95% I.C: 185.4–247.2]) with tumor cell contents of 1% to 100% (mean percentage: 31.3% [95% I.C: 28–34.6]), with 104 (52.5%) samples below the manufacturer’s recommendations for IdyllaTM KRAS mutation testing (i.e., at least 10% of tumor cells content in a tissue area between 50 and 600 mm2 for a 5 μm-thick tissue section). This evidence concerns the gene KRAS and neoplasm.