The in vivo DNA aneuploidization during expansion of conventional renal cell carcinoma

Although numerous studies on the prognostic value of DNA aneuploidy in RCC have been reported, the in vivo DNA aneuploidization during RCC expansion has not been revealed. The present study was undertaken to observe the DNA aneuploidization during RCC expansion. We studied prospectively 67 consecutive conventional RCCs. The ploidy status was determined by analyzing five fresh tumor tissues from different areas by flow cytometry. The diploid, heterogeneous aneuploid tumors and homogeneous aneuploid tumors could be detected, respectively, in 44.8%, 23.9% and 31.3% of cases. The diploid tumors decreased significantly and aneuploid tumors increased significantly as the tumor expanded. The similar DNA content distribution was found between the heterogeneous aneuploid tumors and homogeneous aneuploid tumors. The hypertriploid clone was the most frequent in aneuploid tumors. The tumors of multiple aneuploid clones (16.4%) were mainly found in large-sized tumors. These results suggested that some RCCs underwent DNA aneuploidization during the tumor expansion and that a major route of aneuploidiztion (hypertriploidization) and several pathways existed. Our results also supported the idea that the progressive chromosomal instability was associated with continued tumor growth of RCC. The molecular mechanism and the clinical significance of aneuploidy phenotypes need to be further investigated.