Frequent gain of the human telomerase gene TERC at 3q26 in cervical adenocarcinomas.

The level of genomic amplification of the human telomerase gene TERC, which maps to chromosome band 3q26, was determined in primary cervical adenocarcinomas. Interphase nuclei prepared from archival material of 12 primary cervical adenocarcinomas, eight of which were human papillomavirus positive, were hybridised with a triple colour probe set specific for centromeres of chromosomes 3 and 7 and the TERC gene. We observed high proportions of nuclei with increased absolute copy numbers for TERC in all tumours (mean 3.3; range 2.3-5.2). Amplification of the human telomerase gene TERC is a consistent aberration in cervical adenocarcinomas. Therefore, application of our probe set may provide an objective genetic test for the assessment of glandular cells in Pap smears and hence for the diagnosis of cervical adenocarcinomas.

Gain of chromosome 3q is an early and consistent genetic aberration in carcinomas of the vulva.

The aim was to determine whether specific gains of chromosome 3q and laminin-5gamma2-chain expression can improve early detection of invasive capacity in precancerous and squamous cell carcinoma of the vulva (VSCC). Six VSCC and three precancerous lesions were studied. Multicolor fluorescence in situ hybridization (FISH) probe sets were applied to nuclei suspensions prepared from archival material using the Hedley method. The probe panel consists of the centromers of chromosome 7, chromosome 3, and the TERC gene residing on the long arm of chromosome 3. Laminin-5gamma2-chain immunohistochemical analysis was performed on corresponding specimens and was expressed only in the VSCC. The genome-specific FISH analysis revealed 3q amplification in 43% of the nuclei analyzed for the VSCC and 22% of the nuclei for the precancerous lesions. Low-level 3q amplifications were found in precancerous lesions with an average fold increase of 1.15 for 3q. The invasive lesions showed higher average fold increases for 3q, averaging 1.32. Laminin-5gamma2-chain protein was expressed only in VSCC, whereas 3q gains were observed both in precancerous lesions and in VSCC, indicating that gain of chromosome 3q is an early and consistent event during carcinogenesis of VSCC.

[Interphase cytogenetics with DNA-probes for chromosome 8 to detect circulating tumor cells in breast cancer patients]. / Interphasezytogenetik mit DNA-Sonden für Chromosom 8 zur Detektion zirkulierender Tumorzellen beim Mammakarzinom.

The detection of micrometastases in the bone marrow or peripheral blood of cancer patients is increasingly used for a more sensitive tumor staging and prognostication. The potential value of the currently used techniques for the detection of epithelial antigens by RT-PCR or immunohistochemistry in respect of specificity is currently controversially discussed. In the present study we demonstrate a new approach which enables the direct visualization of the tumor specific alteration of chromosome 8 in circulating tumor cells. We have therefore studied breast cancer patients with various tumor stages and tried to determine the frequency of circulating tumor cells in the peripheral blood by using interphase cytogenetics for chromosome 7 and 8. Imprints of primary breast cancers and cytospins with circulating tumor cells of corresponding patients were studied in a blinded fashion. The blood samples were generated by immunomagnetic enrichment of circulating tumor cells from peripheral blood by ferrofluid and centrifugation onto cover slips. These cytospins were then hybridized with centromer probes 7 and 8. After analyzing 27 patients with benign as well as malignant breast tumors we can demonstrate that the chromosomal pattern between malignant tumor and corresponding circulating tumor cells is identical. Furthermore, the detection of circulating tumor cells directly correlates with the primary tumor stage. We did not find any cells with chromosome 8 alterations in the patients with benign disease. Surprisingly, even in early breast cancers (T1N0) interphase cytogenetics identified circulating tumor cells in 2 out of 4 patients. In conclusion, interphase cytogenetics represent a non-invasive, sensitive and specific assay for the direct visualization of circulating tumor cells in the peripheral blood. The prognostic value of these findings remains to be further evaluated in larger prospective studies.

Jumping translocations are common in solid tumor cell lines and result in recurrent fusions of whole chromosome arms.

Jumping translocations (JTs) and segmental jumping translocations (SJTs) are unbalanced translocations involving a donor chromosome arm or chromosome segment that has fused to multiple recipient chromosomes. In leukemia, where JTs have been predominantly observed, the donor segment (usually 1q) preferentially fuses to the telomere regions of recipient chromosomes. In this study, spectral karyotyping (SKY) and FISH analysis revealed 188 JTs and SJTs in 10 cell lines derived from carcinomas of the bladder, prostate, breast, cervix, and pancreas. Multiple JTs and SJTs were detected in each cell line and contributed to recurrent unbalanced whole-arm translocations involving chromosome arms 5p, 14q, 15q, 20q, and 21q. Sixty percent (113/188) of JT breakpoints occurred within centromere or pericentromeric regions of the recipient chromosomes, whereas only 12% of the breakpoints were located in the telomere regions. JT breakpoints of both donor and recipient chromosomes coincided with numerous fragile sites as well as viral integration sites for human DNA viruses. The JTs within each tumor cell line promoted clonal progression, leading to the acquisition of extra copies of the donated chromosome segments that often contained oncogenes (MYC, ABL, HER2/NEU, etc.), consequently resulting in tumor-specific genomic imbalances. Published 2001 Wiley-Liss, Inc.

Genomic changes defining the genesis, progression, and malignancy potential in solid human tumors: a phenotype/genotype correlation.

The transition of normal epithelium to invasive carcinoma occurs sequentially. In colorectal and cervical carcinogenesis, this transition is reflected by histomorphologically defined grades of increasing dysplasia that untreated may progress to invasive disease. In an attempt to understand the role of chromosomal aberrations during tumorigenesis we have applied comparative genomic hybridization using DNA extracted from defined stages of colorectal and cervical tumors, from low- and high-grade astrocytic tumors and from diploid and aneuploid breast carcinomas. Genetic instability, as measured by the number of chromosomal copy alterations per case, increases significantly at the transition from precursor lesions to invasive carcinomas and continues to increase with tumor stage. Aggressive tumors have a higher number of copy alterations per case. High-level copy number changes (amplifications) become more prevalent in advanced-stage disease. Subtractive karyograms of chromosomal gains and losses were used to map tumor stage-specific chromosomal aberrations and clearly showed that nonrandom chromosomal aberrations occur during disease progression. In colorectal and cervical tumors, chromosomal copy number changes were correlated with nuclear DNA content, proliferative activity, expression levels of the tumor suppressor gene TP53, and the cyclin-dependent kinase inhibitor p21/WAF1, as well as the presence of viral genomes. Here we summarize and review the results of this comprehensive phenotype/genotype correlation and discuss the relevance of stage-specific chromosomal aberrations with respect to diagnostic applications.