FAP and hyperplastic polyposis syndrome: This raises the question of whether this region specifically predisposes individuals to increased gastric cancer risk and a more severe gastric phenotype.; however carpeting gastric polyposis and gastric cancer can be seen in patients with FAP and an underlying pathogenic variant not linked to the promoter 1B region of APC. Certainly, large deletions in promoter 1B often have colonic polyposis and have a very variable phenotype.