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Chromosome 17p deletions and p53 mutations in renal cell carcinoma
1Urologic Oncology Section, National Cancer Institute, Bethesda, Maryland 20892.
Abstract:
Studies of the role of tumor suppressor genes in human renal cell carcinoma from our laboratory have suggested the presence of a disease gene(s) on the short arm of chromosome 3. Little is known about the role other tumor suppressor genes may play in this malignancy. Abnormalities of chromosome 17p and, in particular of p53, are common in many human malignancies. In order to evaluate the role of this region in renal cell carcinoma, we performed restriction fragment length polymorphism analyses of chromosome 17 with probes localized to the p53 region. Fourteen of 29 (48%) evaluable cell lines showed loss of heterozygosity at this locus. Northern blot analysis did not detect a p53 transcript in 4 of 27 cell lines tested. In addition, we screened cell lines for p53 mutations using a polymerase chain reaction-single strand conformation polymorphism technique. Cell lines positive for mutations by this technique were then sequenced. Mutations were detected in 11 of 33 (33%) cell lines, including 8 derived from primary tumors and 3 derived from metastatic foci. Six of 9 (67%) patients with loss of heterozygosity demonstrated a mutation in the remaining allele, while only 1 of 8 (13%) without loss of heterozygosity had a mutation. Three of 3 (100%) cell lines derived from metastases had the same mutation as their matched primary cell line. Loss or mutation of p53 did not correlate either with loss of chromosome 3p or with histological subtype. These results suggest that, while the primary disease gene for kidney cancer appears to be on chromosome 3, abnormalities of p53 are common and may be involved in the progression of this malignancy.
Insights
Tumor suppressor gene p53 abnormalities are common in kidney cancer (renal cell carcinoma), suggesting a role in disease progression, though the primary gene is on chromosome 3.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Renal cell carcinoma (kidney cancer) is linked to tumor suppressor genes on chromosome 3.
- The role of other tumor suppressor genes, like p53 on chromosome 17p, in kidney cancer is not well understood.
- p53 abnormalities are frequent in various human cancers.
Purpose of the Study:
- To investigate the involvement of the p53 tumor suppressor gene in renal cell carcinoma.
- To determine the frequency of p53 alterations (loss of heterozygosity and mutations) in kidney cancer cell lines.
Main Methods:
- Restriction fragment length polymorphism (RFLP) analysis to detect loss of heterozygosity (LOH) at the p53 locus.
- Northern blot analysis to assess p53 gene expression.
- Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by sequencing to identify p53 mutations.
Main Results:
- 48% of evaluable kidney cancer cell lines showed LOH at the p53 locus.
- p53 transcript was undetectable in 4 out of 27 cell lines.
- Mutations in p53 were found in 33% of cell lines; 67% of those with LOH had a mutation in the remaining allele.
- Mutations in matched primary and metastatic cell lines were identical (100%).
- p53 alterations did not correlate with chromosome 3p loss or histological subtype.
Conclusions:
- While the primary kidney cancer gene is likely on chromosome 3, p53 abnormalities are prevalent in renal cell carcinoma.
- p53 alterations may play a significant role in the progression of kidney cancer.
- p53 mutations are common in both primary and metastatic kidney cancer.