Ovarian malignant mixed mesodermal tumor with neuroectodermal differentiation: a multifaceted evaluation.

Malignant mixed mesodermal tumors (MMMTs) of the ovary are rare, highly aggressive neoplasms that arise most commonly in postmenopausal women. Histologically, they consist of a mixed population of malignant epithelial and mesenchymal elements. Neuroectodermal differentiation in ovarian MMMTs is exceedingly uncommon, with only a few case reports in the literature. We present a case of an ovarian MMMT with neuroectodermal differentiation in a 78-year-old female patient. Histologically, the tumor was composed of epithelial, mesenchymal, and neuroectodermal elements. The neuroectodermal component was predominantly that of a medulloepithelioma, with scattered areas displaying features of an anaplastic astrocytoma, including rare ganglion cell differentiation. The neuroectodermal component showed immunoreactivity for glial fibrillary acidic protein, synaptophysin, and S100 protein. Ultrastructurally, the neuroectodermal component was populated by cells with irregular nuclei, finely dispersed chromatin, rudimentary cell junctions, and a delicate basement membrane, all of which have been described in medulloepitheliomas. DNA ploidy analysis was also performed on the various components of the tumor and compared with 3 additional cases of MMMT without neuroectodermal differentiation and 2 ovarian immature teratomas. Our findings suggest that the neuroectodermal component may arise from a separate clone or at least evolves at an earlier stage of tumor development.

[Estimation of DNA methylation level in nonendometrial uterus malignancies]. / Ocena poziomu metylacji DNA w tkankach zlosliwych nowotworów nienablonkowych trzonu macicy.

OBJECTIVES: Rebuilding of genome structure leads to many pathological states including neoplastic malignancies. Rebuilding often occurs as a process caused by disturbances in gene silencing mechanism. DNA methylation pattern is one of the most important mechanisms connected to gene's silencing. Estimation of DNA methylation level in nonendometrial uterine neoplastic tissues compared to normal endometrial samples was the aim of this study. DESIGN: It was to be shown, that changes in methylation rate in promotory regions could lead to carcinogenesis in particular cell. Authors describe an analysis of DNA methylation level in nonendometrial neoplastic uterine tissues compared to DNA methylation level in normal endometrium. MATERIALS AND METHODS: Tissue samples from 9 women with tumor mixtus mesodermalis were collected. 12 samples were normal endometrium-control group. DNA was isolated from tissues and than we performed an estimation of DNA methylation levels. Than we performed a statistical analysis of results. RESULTS: The median DNA methylation level was significantly higher in neoplastic tissues than in normal endometrium. CONCLUSIONS: Authors conclude, that DNA methylation level is higher in neoplastic tissues, but does not correlate with clinical stage of the disease.

Ovarian cancer: loss of heterozygosity frequently occurs in the ATM gene, but structural alterations do not occur in this gene.

Ataxia-telangiectasia is a multisystem recessive disease characterized clinically by cerebellar ataxia, oculocutaneous telangiectasias, immunodeficiency, sensitivity to radiomimetic agents and an increased predisposition to cancer. This pleiotropic disorder is caused by mutations in the ATM gene, which is located at the human chromosomal region 11q23. Loss of heterozygosity (LOH) at 11q22-q23 is a frequent event in ovarian cancer, suggesting the presence of a tumor suppressor gene in this region. We have found that LOH in the ATM gene occurred in 44% of informative cases in a series of 22 primary ovarian tumors. LOH of this region occurred at the same frequency during the advanced stages (III-IV; 3/9, 33%) as in the early stages (I-II; 4/13, 31%) of ovarian cancer. To investigate the role of ATM in ovarian cancer, we used a PCR-based single-strand conformation polymorphism assay for mutation detection of the entire coding sequence of the ATM gene (65 exons) in 22 ovarian tumors. No somatic alterations of the ATM gene were found in these ovarian cancer samples including those with LOH present in the ATM gene. Our study has identified a region (11q23) which probably contains a frequently altered tumor suppressor gene in ovarian cancer, and this gene does not appear to involve the coding sequences of the ATM gene.

Cytogenetic findings in malignant mixed mesodermal tumors of the uterus.

Cytogenetic analyses of four malignant mixed mesodermal tumors (MMMT) of the uterus are reported, of which one was of the homologous type and three of the heterologous. Karyotypic analyses were obtained in two cases from original tumors and in two cases from tumors xenotransplanted into nude mice. The karyotype of the homologous MMMT was normal in three different passages of a nude mice xenograft line established from the primary tumor. The heterologous tumors showed normal karyotype in one case and hyperdiploid and near triploid range with extensive numerical and structural rearrangements in two cases. Deletion of chromosome 1 at p32, and deletion of chromosome 11 at q13 were common markers in anomalous cases. The chromosomes most often involved in structural rearrangements were chromosomes 1, 9, 11, 12, 17, and 19. Double minutes, homogeneously staining regions, and telomeric association were also seen.

Cytogenetic findings in four malignant mixed mesodermal tumors of the ovary.

Short-term cultures of four malignant mixed mesodermal tumors of the ovary were cytogenetically analyzed. The primary tumor was examined in three cases, whereas in one case the sample was obtained from a residual tumor mass after chemotherapy. The tumor sampled after cytostatic treatment had a relatively simple karyotype with numerical changes that included pentasomy 12 and an i(1)(q10) as the only structural abnormality. Karyotypic analysis of the three primary tumors revealed extensive structural as well as numerical aberrations, i.e., a picture similar to that seen in the few malignant mixed mesodermal tumors with karyotypic anomalies described previously. Rearrangements of chromosome 1, leading to loss of distal 1p, and homogeneously staining regions have so far been the most frequent cytogenetic changes in this tumor type. Malignant mixed mesodermal tumors of the ovary thus seem to be karyotypically identical to the more numerous mixed mesodermal tumors of uterine origin, and they do not differ substantially in this respect from pure ovarian carcinomas.

The expression of epidermal growth factor receptor, HER-2/Neu, p53, and Ki-67 antigen in uterine malignant mixed mesodermal tumors and adenosarcoma.

Uterine malignant mixed mesodermal tumors (MMMT) are highly malignant tumors containing both malignant glands and stroma, while adenosarcomas (AS) are less aggressive tumors composed of malignant stroma and benign glands. Immunohistochemistry was used to grade overexpression of p53 protein, HER-2/neu protein, epidermal growth factor receptor (EGFR), and Ki-67 antigen in both the glands and stroma of tissue from 20 women with MMMT and 6 women with AS. EGFR was overexpressed in 2 AS and 9 MMMT, and was more commonly found in the sarcomatous component than the carcinomatous component in MMMT (P = 0.03). p53 was not found in any AS samples and was strongly present in 6 MMMT samples with a random distribution between the malignant components. HER-2/neu protein was not overexpressed in any AS or primary MMMT. Ki-67 antigen, a marker of cell proliferation, was found at higher levels in MMMT than AS samples (P = 0.03) and high Ki-67 antigen expression correlated with a decreased survival in patients with MMMT (P = 0.004). Independent characterization of oncogene proteins in the malignant components of these heterogeneous tumors may provide insight into the histogenesis and behavior of these malignancies.

Microsatellite instability in gynecological sarcomas and in hMSH2 mutant uterine sarcoma cell lines defective in mismatch repair activity.

We have examined a panel of gynecological sarcomas for microsatellite instability. The genomic DNA from 11 of 44 sarcomas contained somatic alterations in the lengths of one or more di-, tri-, tetra-, or pentanucleotide microsatellite sequence markers, and 6 of these cases had alterations in two or more markers. In addition, di-, tri-, and tetranucleotide microsatellites were found to be highly unstable in single cell clones of two cell lines derived from a uterine mixed mesodermal tumor. Since such instability is characteristic of cells defective in postreplication mismatch repair, we examined mismatch repair activity in extracts made from these lines. Both extracts were repair deficient, while an extract of another gynecological sarcoma cell line not exhibiting microsatellite instability was repair proficient. The repair deficiency was complemented by a colon tumor cell extract that was defective in the hMLH1 protein but not by an extract defective in hMSH2 protein. This suggested that the defect in the uterine sarcoma line could be in hMSH2. Subsequent analysis of the gene revealed a 2-bp deletion in exon 14, leading to premature truncation of the hMSH2 protein at codon 796 and no detectable wild-type gene present. These data suggest that the microsatellite instability observed in these cell lines, and possibly in a significant number of gynecological sarcomas, is due to defective postreplication mismatch repair. There was no apparent correlation with microsatellite instability and clinical outcome.

Chromosome 11 allele imbalance and clinicopathological correlates in ovarian tumours.

Allele imbalance on chromosome 11 loci in ovarian cancer is a frequent event, suggesting the presence of tumour-suppressor genes for ovarian carcinogenesis on this chromosome. Ten highly polymorphic (CA) repeat microsatellites were used to determine allele imbalance in 60 primary ovarian tumours, including 47 epithelial ovarian cancers (EOCs). Forty EOCs (85%) showed allele imbalance at one or more loci, and in 39 of these (83%) the data suggested subchromosomal deletions: eight of 11p only; six of 11q only; and 25 of both 11p and 11q. Three consensus regions of deletion were indicated at 11p15.5-p15.3, 11q12-q22 and 11q23.3-q24.1. Allele imbalance at the 11q subtelomeric region (D11S912) correlated significantly with adverse survival, while imbalance at 11q14.3 and retention of heterozygosity at 11q22 (close to the site of the progesterone receptor gene) were associated with favourable clinicopathological features. The findings allow development of a preliminary model for the molecular evolution of epithelial ovarian cancer.