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Chromosome instability (CIN) is gaining increasing interest as a central process in cancer. CIN, either past or present, is indicated whenever tumour cells harbour an abnormal quantity of DNA, termed 'aneuploidy'. At present, the most widely used approach to detecting aneuploidy is DNA cytometry - a well-known research assay that involves staining of DNA in the nuclei of cells from a tissue sample, followed by analysis using quantitative flow cytometry or microscopic imaging. Aneuploidy in cancer tissue has been implicated as a predictor of a poor prognosis. In this Review, we have explored this hypothesis by surveying the current landscape of peer-reviewed research in which DNA cytometry has been applied in studies with disease-appropriate clinical follow up. This area of research is broad, however, and we restricted our survey to results published since 2000 relating to seven common epithelial cancers (those of the breast; endometrium, ovary, and uterine cervix; oesophagus; colon and rectum; lung; prostate; and bladder). We placed particular emphasis on results from multivariate analyses to pinpoint situations in which the prognostic value of aneuploidy as a biomarker is strong compared with that of existing indicators, such as clinical stage, histological grade, and specific molecular markers. We summarize the implications of our findings for the prognostic use of ploidy analysis in the clinic and for the theoretical understanding of the role of CIN in carcinogenesis.

Sex cord-stromal tumors of the ovary comprise 8% of all ovarian neoplasms. Because they consist of cells that resemble embryonic sex cord and/or specialized ovarian stroma cells, their cytologic and histologic features can be viewed as reflecting a continuum from fibromas to thecomas with thecofibromas in between. Existing cytogenetic knowledge about ovarian thecomas-thecofibromas-fibromas is restricted to 44 cases with chromosomal abnormalities. The most common aberration has been trisomy 12, identified either by karyotyping or using fluorescence in situ hybridization (FISH). We wanted to obtain more information about the genomic composition of these tumors, and, therefore, examined 29 new thecoma-thecofibroma-fibroma tumors of the ovary using karyotyping, comparative genomic hybridization, interphase FISH, and DNA ploidy analysis. We detected aneuploidy in 21 tumors. Trisomy and/or tetrasomy 12 was the most common chromosomal aberration, found in 15 tumors (71.5% of the aneuploid tumors or 51.5% of all analyzed tumors), followed by trisomy for chromosomes 10, 18, 4, and 9. Some monosomies (for chromosomes 4, 9, 10, and 18) were also identified, either as the sole change or in combination with trisomies. The nonrandom occurrence of these aneuploidies in these benign tumors strongly indicates that they play a major pathogenetic role, but how trisomies and other aneuploidies contribute to tumorigenesis remains unknown.

Image cytometric DNA ploidy analysis of endometrial carcinomas was performed to determine whether ploidy status and ploidy-related parameters like DNA index, percentage of cells exceeding 5c and 9c, correlate with histologic subtype. This is a prospective study of 391 patients with stage I endometrial carcinoma which included 331 (85%) endometrioid adenocarcinoma, 22 (6%) serous adenocarcinoma, 7 (2%) clear cell adenocarcinoma, 2 (0.5%) small cell carcinoma, 1 (0.3%) undifferentiated carcinoma, and 28 (7%) unclassifiable adenocarcinoma. Twenty-five percent of endometrioid adenocarcinomas were non-diploid. In contrast, all clear cell adenocarcinomas and 21/22 (95%) of serous adenocarcinomas were non-diploid. Hyperdiploidy (25 cases) was found only in endometrioid adenocarcinomas. Mean DNA index of the stemline in serous adenocarcinoma (1.72) and clear cell adenocarcinoma (1.81) was higher than in endometrioid adenocarcinoma (1.1). The difference in ploidy-related parameters between endometrioid adenocarcinoma and serous adenocarcinoma was highly significant (P<0.001). In addition, Grade 3 endometrioid adenocarcinoma showed significant difference in all ploidy-related parameters compared with grade 1 and grade 2 tumors (P<0.001). Our results show that DNA ploidy-related parameters may be valuable in subtyping histologically difficult cases of endometrial carcinomas., (Published online 26 May 2006.)

Abstract: DNA ploidy analysis is useful for prognostication in cancer patients, but the genomic details underlying ploidy changes are not fully understood. To improve this understanding, we compared DNA ploidy status with karyotypic and comparative genomic hybridization data on 51 endometrial adenocarcinomas. Out of 34 DNA diploid tumors evaluated by CGH, 16 (47%) showed imbalances, though only two had more than four copy number changes. Ten (29%) had aberrations involving chromosome 1, seven (21%) involving chromosome 10, while one tumor had a chromosome 8 aberration. Four of the seven DNA tetraploid tumors (57%) had imbalances detected by CGH with two (29%) having more than four. Six out of eight DNA aneuploid tumors showed imbalances by CGH, with five (63%) having more than four. The aberrations were observed on chromosomes 1 and 8 in five/eight (63%) cases while four imbalances (50%) involved chromosomes 5, 7 and X. Not surprisingly, we observed a significant correlation between increasing DNA ploidy complexity and increasing number of copy alterations. Gains of material from chromosomes 8 and 7 might be specifically correlated to DNA aneuploidy in endometrial adenocarcinomas since 63% and 50% of the aneuploid compared to 3% of the diploid tumors showed imbalances involving these chromosomes. [Copyright &y& Elsevier]

Summary: Giant cell ependymoma, a rare ependymoma subtype, was recently recognized as a separate diagnostic entity with variations both in malignant potential and course of disease. We analyzed the first supratentorial giant cell ependymoma using G-band karyotyping, DNA ploidy analysis, and array comparative genomic hybridization. The tumor was hypodiploid, and the karyotype showed multiple monosomies. This novel cytogenetic pattern seems specific for giant cell ependymoma as the only previous cytogenetic analysis of a giant cell ependymoma found similar monosomies. We were also able to analyze cytogenetically the subsequent recurrent tumor, phenotypically an anaplastic ependymoma, allowing a first insight into the genetic events involved in disease progression. [ABSTRACT FROM AUTHOR]

Malignant ovarian germ cell tumors (mOGCT) affect women in their reproductive years, making fertility-saving treatment important. A reliable prediction of the clinical behavior is essential for an optimal therapeutic approach. The genetic changes and molecular mechanisms underlying these rare tumors remain poorly understood. To address these issues, we performed DNA ploidy analysis by high-resolution image cytometry in a series of 47 mOGCT and correlated the findings with the DNA copy number changes detected by comparative genomic hybridization (CGH) and clinical outcome. Of 47 tumors, 15 were diploid, 14 were tetraploid, 2 were polyploid, and 13 were aneuploid. All the immature teratomas were diploid, in contrast to the dysgerminomas and endodermal sinus tumors. The International Federation of Gynecology and Obstetrics (FIGO) staging, residual tumors after surgery, and DNA ploidy distribution were significant, independent prognostic factors in survival analysis. The study revealed that the number of DNA copy number aberrations was increased in tetraploid and aneuploid tumors as compared to diploid tumors. Furthermore, a high percentage of aneuploid nuclei in a sample were associated with a complex CGH profile of the tumor in question. The present study confirms that DNA aneuploidy assessment by image analysis may be linked to genetic instability, which is detected as genetic aberrations by CGH. DNA ploidy gives significant prognostic information in addition to the clinical stage in mOGCT with FIGO stage II–IV. [Copyright &y& Elsevier]