Loss of heterozygosity in tumour-adjacent normal tissue of breast and bladder cancer.
Normal tumour-adjacent breast tissue samples from 12 breast cancer patients forming six monozygotic twin pairs were analysed for loss of heterozygosity (LOH) on chromosomes 1, 13 and 17. 7 patients showed LOH at one or more markers. Each of them had a different LOH pattern. Only one twin pair showed LOH at the same locus, but the twins had lost a different allele. Multiple (n=1-13), histologically normal samples were collected from 6 bladder cancer patients and analysed for LOH on chromosomes 3 and 9. On chromosome 9, all 6 patients analysed showed LOH in at least one sample and one marker. Four of them also showed LOH on chromosome 3. Samples surrounding different tumours of a given patient resembled each other. More heterogeneity was seen between the patients, even though they shared some similarities in LOH clustering. The results demonstrate that tumour-adjacent normal tissues already harbour genetic changes typical for tumours. These alterations can reveal the earliest changes leading to tumorigenesis.
Försti
A
A
Department of Biosciences at Novum, Karolinska Institute, S-14157, Huddinge, Sweden. asta.forsti@cnt.ki.se
Louhelainen
J
J
Söderberg
M
M
Wijkström
H
H
Hemminki
K
K
D001943:Breast Neoplasms / Q000235:genetics*; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D006801:Humans; D019656:Loss of Heterozygosity; D018895:Microsatellite Repeats; D014430:Twins, Monozygotic; D001749:Urinary Bladder Neoplasms / Q000235:genetics*