FossB, S. D. DNA-variations in neighbouring epithelium in patients with bladder carcinoma.Acta path. microbiol. scand. Sect. A, 85: 603-610, 1977. Histologically atypical urothelium taken from bladder mucosa neighbouring transitional cell carcinoma showed similar, though less marked, DNA-changes as observed in the corresponding tumours. A definite increase in the numiber of non-diploid DNA-values was found in 6 (of 12) urothelial specimens. The clinical significance of urothelial DNA-changes is discussed.