Correlation of DNA hypomethylation at pericentromeric heterochromatin regions of chromosomes 16 and 1 with histological features and chromosomal abnormalities of human breast carcinomas.

Changes in DNA methylation status are not only important for regulating gene expression but are also suggested to induce chromosome instability. To reveal the correlation of DNA methylation status in heterochromatin regions with tumor histology and with chromosome alterations, DNA methylation status was examined by Southern blot analysis, and numerical and structural chromosome alterations, including the formation of der(16)t(1;16)/der(1;16), were examined by fluorescence in situ hybridization at the two loci in the pericentromeric satellite 2 regions of chromosomes 16 and 1 in 39 human breast carcinomas. DNA hypomethylation at the D16Z3 and the D1Z1 loci was detected in 31% (12 of 39) and 36% (12 of 33) of carcinomas, respectively, and mostly concurred.

Allelotype analysis of common epithelial ovarian cancers with special reference to comparison between clear cell adenocarcinoma with other histological types.

Determination of the histological type of epithelial ovarian cancer is clinically important to predict patient prognosis. To estimate accurately the chromosomal regions that frequently show loss of heterozygosity (LOH) in each histological type, LOH at 55 loci on 38 chromosomal arms was examined by means of laser capture microdissection and PCR-LOH analysis in 45 epithelial ovarian cancers composed of clear cell adenocarcinoma (CCA), serous adenocarcinoma (SEA), endometrioid adenocarcinoma (EMA) and mucinous adenocarcinoma (MUA). In addition, p53 (exons 5 - 8) gene mutations and the nuclear immunoreactivity of p53 proteins in these tumors were examined by PCR-SSCP and immunohistochemistry.

Different pattern of loss of heterozygosity among endocervical-type adenocarcinoma, endometrioid-type adenocarcinoma and adenoma malignum of the uterine cervix.

It is unclear which chromosome arms frequently show loss of heterozygosity (LOH) in adenocarcinoma of the uterine cervix. To identify such chromosomal arms, LOH on 52 different chromosome loci was examined using laser capture microdissection and PCR-LOH analysis in 25 common-type adenocarcinomas, comprising 13 cases of endocervical type, 12 cases of endometrioid type and 7 cases of adenoma malignum without the component of conventional endocervical-type adenocarcinoma (designated as "pure" form). In adenocarcinomas of endocervical type and endometrioid type, LOH was commonly detected on chromosome arms 17p (62% and 50%, respectively), 1p (33% and 67%) and 22q (40% and 33%).