APC and colorectal carcinoma: By contrast, InSiGHT recommends that enhanced screening for CRC in APC I1307K heterozygotes/homozygotes should be restricted to individuals of AJ ancestry (as per enhanced screening offered to individuals with a first-degree relative affected with CRC), but that there should be no enhanced screening for non-AJ I1307K individuals because the risk association has not been proven for non-AJ ethnicities.