Contribution of Chromosome 9p21‐22 Deletion to the Progression of Human Renal Cell Carcinoma

To investigate the possible role of genomic aberrations of chromosome 9p21‐22 in the tumorigenesis of human renal cell carcinoma (RCC), 10 RCC cell lines, 55 primary RCCs and 5 metastatic lesions were studied by Southern blotting and polymerase chain reaction‐based analysis. Nine of 10 RCC cell lines showed a homozygous deletion of MTS1/CDKN2/(p16), while only 1 in 55 primary tumors had this deletion. Loss of heterozygosity on 9p21‐22 was observed in 5 of 10 informative primary RCCs from patients with metastasis, but in only 4 of 31 informative tumors (13%) without metastasis (P= 0.025). Furthermore, 3 of 5 metastatic tumors (60%) showed hemi‐ or homozygous deletion of MTS1/CDKN2. These results indicate that the 9p21‐22 deletion may be a relatively late event in RCC tumorigenesis and could be associated with RCC metastasis.