Radiation sclerosing proliferative atypical nephropathy of peritumoral tissue of renal-cell carcinomas after the Chernobyl accident in Ukraine

After the Chernobyl accident, the morbidity of renal-cell carcinomas in Ukr aine increased gradually from 4.7 to 7.5 per 100,000 of the total populatio n. Cesium 137 (Cs-137) is responsible for 80-90% of the internal radioactiv ity in people living in radiocontaminated areas of Ukraine, and 90% of Cs-1 37 is eliminated through the kidneys. Histological and immunohistochemical study of proliferating cell nuclear antigen (PCNA) and K-rns protein was pe rformed in peritumoral kidney tissues of 167 Ukrainian patients (groups I-I II, according to varying degrees of internal exposure to radiation), and of 85 analog Spanish patients, as a control group. Our data showed in the maj ority of Ukrainian patients a radiation sclerosing proliferative atypical n ephropathy (RSPAN) in association with an increase in the incidences of tub ular epithelial nuclear atypia and carcinoma in situ (CIS). Areas of epithe lial nuclear atypia and CIS of the cortex and medulla showed significant PC NA expression with means of extent as 12, 14, and 15% of stained nuclei in groups I, II, and III respectively. K-ras expression of the same areas occu rred in 67, 87, and 85% of cases in groups I, II, and III respectively. The present study points to a strong relationship between the long term of low -dose radiation exposure of the Ukrainian population and the development of RSPAN as a possible precursor of malignancy. In addition, it confirms the possible initiator, promoter, or progressor role of chronic low-level radia tion of renal human carcinogenesis in Ukraine.