Frequent multiplication of chromosome 1q in non-invasive and papillotubular carcinoma of the breast.
Carcinogenesis is considered to be a multistep process that may involve cumulative genetic alterations; one of these mechanisms, gain of chromosomal material, has the potential to activate tumor-promoting genes in breast carcinogenesis. Using 12 polymorphic microsatellite markers on the long arm of chromosome 1 (1q), we examined 130 sporadic breast carcinomas for abnormalities in the copy numbers of these loci in tumor cells using a differential PCR method. We also sought correlations between alterations on 1q and several clinicopathological parameters. At every locus examined, a 2-3-fold increase in copy number of an allele in tumor material was observed in one third of the tumors (46 of 130, 35%), indicating 'multiplication' of 1q. This multiplication involved the entire long arm in majority of those tumors (43 cases, 93%). The multiplication of 1q was observed more frequently in non-invasive ductal and papillotubular histological types than in solid-tubular and scirrhous types (13/25, 52% vs. 27/90, 30%) (P = 0.041). The predominant chromosomal alterations on 1q in breast carcinomas are found to be multiplications rather than losses. The multiplication represents polysomy of the entire region of 1q, and may confer a growth advantage during development and/or progression of non-invasive ductal and papillotubular histologic types of breast carcinomas.
Tsukamoto
K
K
Department of Molecular Biology, Institute of Gerontology, Nippon Medical School, Kawasaki, Japan.
Yoshimoto
M
M
Kasumi
F
F
Akiyama
F
F
Sakamoto
G
G
Nakamura
Y
Y
Emi
M
M
D000231:Adenocarcinoma, Papillary / Q000235:genetics*; D000483:Alleles; D000782:Aneuploidy; D001943:Breast Neoplasms / Q000235:genetics*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000235:genetics*; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D003720:Densitometry; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007621:Karyotyping; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction