Chronic abuse of the
analgesic drug phenacetin is associated with an increased risk of development of
transitional cell carcinomas of the urinary tract. It is unclear whether
phenacetin acts through chronic tissue damage (
phenacetin nephropathy) or via a genotoxic metabolite causing promutagenic DNA lesions. In the present study, we investigated 15 urothelial
carcinomas from 13 patients with evidence of
phenacetin abuse.
Tumors were screened for p53 mutations in exons 5-8 by single-strand conformation polymorphism (SSCP) analysis, followed by direct sequencing of PCR-amplified
DNA. p53 Mutations were detected in 8/14 primary
tumors (57%). All except one were missense mutations located in exon 5 (three mutations), exon 6 (one), exon 7 (two) and exon 8 (one). The type of mutation varied, with a preference for CpG sites. A frameshift mutation resulting from the insertion of a single
cytosine at
codons 151/152 was detected in a
bladder tumor and its lung
metastasis. Urothelial
carcinomas located in the renal pelvis and in the ureter of the same patient exhibited two different mutations, strongly suggesting that they developed independently. Another patient had
tumors in the renal pelvis and bladder, both of which contained the same p53 mutation, indicating intracavitary metastatic spread. This demonstrates that screening of p53 mutations allows the clonal origin of
tumors in patients with multiple primary and metastatic lesions to be determined. None of the
tumors investigated contained mutations in
codons 12, 13 or 61 of H-ras or K-ras protooncogenes.