We found that compared with the groups with simple papillae of different quantities, the group 3 which had only complex branching architectures showed significantly higher frequencies of both concurrent and subsequent neoplasia of endometrium and also presented significantly more cases with loss of PAX2 expressions and more concordant single KRAS mutations occurring in both the PPE lesions and neoplasia endometrial tissues, while no difference was found between the other two groups. The gene discussed is KRAS; the disease is neoplasm.