Study on clonal origin of renal clear renal carcinoma by X-chromosome inactivation patterns

Objective To investigate the clonal origin of renal clear cell carcinomas （cc-RCC）. Methods Tissue DNA was extracted from 15 female cc-RCC and the corresponding normal kidney tissues, and digested by methylation sensitive restriction endonuclease HhaI. HUMARA fragment was amplified by using polymerase chain reaction （PCR） and the product was electrophoresed and silver stained to show the length polymorphism. Results In the 15 cases, heterozygosity of HUMARA was observed in 13 （86. 7% ）. Loss of heterozygosity （LOH） of HUMARA on X-chromosome, representing monoclonal ori- gin, was 84. 6% （ 11/13 ） for cc-RCC and 7.7% for normal kidney tissue, respectively （P 〈 0. 05）. There was no significant difference among different stages and pathological grades of cc-RCC （ P 〉 0.05 ）. Conclusion RCC is a kind of monoclonal origin tumor and the clonality is not significantly associated with tumor staging and grading Key words: Renal carcinoma ;  X-chromosome ;  Inactivation