Aneuploidy in carcinomas may be initiated by the acquisition of a single trisomy

Karyotypic studies of eight endometrioid carcinomas of the endometrium in this laboratory, four colorectal polyps (from this laboratory or reported in the literature), and four early carcinomas of the ovary (from the literature), provide evidence that clonal evolution leading to malignant neoplasms at these sites originates when a cell acquires a single additional chromosome. In different tumors, different chromosomes may be involved in this change from euploidy to aneuploidy. Since the resultant clones of trisomic cells occur at an early stage of tumor development, their presence is only likely to be determined when they are at a location that is accessible for study. As aneuploidy is a virtually constant feature of malignancy, the possibility that the concept of a single trisomy as the initial event in the development of all malignant solid neoplasias should be addressed.     

Numerical chromosomal changes in DNA hypodiploid solid tumors: restricted loss and gain of certain chromosomes.

BACKGROUND: DNA hypodiploidy is a unique and rare finding associated with aggressive behavior in solid tumors. Identifying the chromosomal changes underlying this feature may provide important information on the development and progression of these neoplasms. METHODS: Fluorescence in situ hybridization analysis using alpha-satellite probes for nine autosomes and the two sex chromosomes was performed on interphase cells from 27 solid tumors which had been shown to be DNA hypodiploid by flow cytometry. The chromosomal abnormalities were correlated with the DNA index and tumor subtypes. RESULTS: The data show mutually exclusive loss of certain chromosomes and compensatory gain of other chromosomes in different tumors. The net loss was slightly more than the net gain for the chromosomes tested. Polysomy of chromosome 7 and monosomy of chromosomes 17, X and loss Y were found in most tumors. Significant differential loss of chromosomes 6,10, and 12 among DNA hypodiploid breast, kidney and lung carcinomas was noted. CONCLUSIONS: Our study shows (i) gain of chromosome 7 and loss chromosome 17 in most DNA hypodiploid tumors, (ii) specific chromosomal loss was noted in breast and renal cell carcinomas, and (iii) that different mechanisms for DNA hypodiploid and hyperdiploid development may exist.     

Recurrent chromosome alterations in transitional cell bladder carcinomas.

A karyotype study was performed in 42 cases of transitional cell bladder carcinoma. The results, confirmed by DNA content evaluation, showed a prevalence of near-diploid modes not related to the histologic grade of differentiation. Nonrandom alterations were represented by monosomy of chromosome 13 and 22, trisomy of chromosome 7 and deletion of chromosomes 6 and 11. These anomalies allow the identification of different sub-groups of tumors, each with its own biological characteristics of aggressiveness. Prognosis was particularly poor in cases with monosomy of chromosomes 13 and 22 but more favourable in poorly differentiated carcinomas with trisomy of chromosome 7.     

Cytogenetic diversity in primary human tumors

Cytogenetic patterns from primary short-term culture of breast cancer, renal carcinoma, and tumors of the central nervous system are presented to illustrate the range of karyotypic diversity of human solid tumors as well as their biologic differences in culture systems that support their growth. These studies have illustrated several major issues. 1) Results vary with the tissue of origin: primary cultures from breast are almost uniformly diploid, while renal tumors are near-diploid, mosaic, and show clonal aberrations; and CNS tumors are heterogeneous: some diploid, some near-diploid and some highly aneuploid. 2) Results after short-term culture are selective, representing subpopulations from the heterogeneous cells that are detected on direct analysis of fresh tumors by cytogenetics or flow cytometry (FCM). It is not yet clear whether prognosis depends on the dominant population of the primary tumor or alternatively should be influenced by detection of small aneuploid subpopulations. 3) Evidence from all three tumor types supports the interpretation that cytogenetically normal diploid cells constitute part of some tumor populations, and may be better adapted to routine growth in culture than aneuploid subpopulations from the same primary tumors. These cells may also compose a major portion of the viable population of tumors in vivo and, therefore, could represent a useful model for studies of tumorigenesis and therapeutic regimens.     

Ploidy disturbances in endometrial and ovarian carcinomas. A review

A survey of DNA and chromosome aberrations in human endometrial and ovarian carcinomas is presented, including data obtained by chromosome analysis, absorption cytophotometry and flow cytometry. Nearly all of the cancers showed some structural or numerical chromosomal abnormalities. Endometrial carcinomas were reported to have a near-diploid DNA content in two-thirds of the cases, as opposed to ovarian carcinomas, in which only one-third of the tumors were near diploid. DNA aberrations in tumors of both origins seemed to be associated with an unfavorable prognosis, indicating that DNA measurements may supply a valuable additional criterion for biologic malignancy. Evaluable data on ploidy correlated to histologic subtypes was not available; in general, the number of patients in each study was small. Tumors of low differentiation tended more often to be aneuploid, but this was not a consistent finding. Further research comparing disease stage, tumor grade and tumor type in larger series of patients is therefore mandatory.     

Deletions of the long arm of chromosome 10 in progression of follicular thyroid tumors

Previous studies of follicular thyroid tumors have shown loss of heterozygosity (LOH) on the short arm of chromosome 3 in carcinomas, and on chromosome 10 in atypical adenomas and carcinomas, but not in common adenomas. We studied LOH on these chromosomal arms in 15 follicular thyroid carcinomas, 19 atypical follicular adenomas and 6 anaplastic (undifferentiated) carcinomas. Deletion mapping of chromosome 10 using 15 polymorphic markers showed that 15 (37.5%) of the tumors displayed LOH somewhere along the long arm. Thirteen of these tumors showed deletions involving the telomeric part of chromosome 10q, distal to D1OS 187. LOH on chromosome 3p was found in 8 (20%) cases. Seven of these also showed LOH on chromosome 10q. In eight cases LOH was seen on chromosome 10q but not 3p. In comparison, the retinoblastoma gene locus at chromosome 13q showed LOH in 22% of the tumors. Most of these also had deletions on chromosome 10q. The results indicate that a region at the telomeric part of 10q may be involved in progression of follicular thyroid tumors.     

Chromosome analysis of a primary carcinoma of the Fallopian tube

Summary It is reported on the first chromosome analysis of a primary carcinoma of the Fallopian tube by direct chromosome preparation. A hypodiploid stem-line and a heteroploidy with a wide range of chromosome number were found. One or several marker chromosomes could be detected in 69 of 83 metaphases investigated. These chromosomal findings are comparable to those of other carcinomas of the genital tract except the carcinoma of the endometrium.     

Chromosomal changes in cell lines from mouse tumors induced by nickel sulfide and methylcholanthrene

Rhabdomyosarcomas were induced in mice by intramuscular injections of crystalline nickel sulfide and 3-methylcholanthrene. At early passage, karyotypes were performed by G-banding for four nickel sulfide cell lines and for three 3-methylcholanthrene cell lines. Six cell lines were near-diploid and one nickel sulfide line was near-tetraploid. Three of the nickel sulfide cell lines were characterized by a rearranged marker chromosome which was present in a majority of the cells of each line. The rearrangements leading to the formation of marker chromosomes were different in each nickel sulfide cell line but involved chromosome 4 in two of the nickel sulfide cell lines. Extra copies of chromosome 15 were present in two nickel sulfide cell lines. Possible rearrangement and/or gene activation was examined for the c-mos oncogene on chromosome 4 and the c-myc oncogene on chromosome 15, but no alteration or activation was observed. None of the 3-methylcholanthrene cell lines contained rearranged marker chromosomes; however, one MCA cell line did contain large numbers of double minutes. In all cell lines, minichromosomes (small atypical acrocentric chromosomes) were observed that contained distinct centromeric regions but no other G-positive bands.Abbreviations DHFR dihydrofolate reductase - MCA 3-methylcholanthrene - NS nickel sulfide     

Autophagy in endometrial carcinomas and prognostic relevance of 'stone-like' structures (SLS): what is destined for the atypical endometrial hyperplasia?

Autophagy, as an intracellular adaptation mechanism for oxygen and nutrient deprivation, is associated with tumor cell survival and aggressiveness. This was reaffirmed in a series of 360 endometrial carcinomas, using a standard immunohistochemical technique and the LC3A antibody, capable of recognizing both the soluble (LC3A-I) and the membrane-bound form (LC3A-II) of the protein. LC3A reactivity was recognized in three basic patterns-diffuse cytoplasmic, cytoplasmic/juxta-nuclear, and the so-called "stone-like" structures (SLS). The latter has emerged as the: hallmark of autophagic activity, being detected exclusively in endometrial carcinomas and their immediate precursor lesions, namely the atypical hyperplasias, albeit in small numbers. Other forms of hyperplasia without cytological atypia and normal endometrial tissues expressed only cytoplasmic staining patterns. High SLS counts, presumed to reflect excessive levels of autophagic activity, were associated with tumors of extremely poor prognosis. In contrast, a basal level of autophagic activity, as exemplified by the diffuse cytoplasmic and the cytoplasmic/juxta-nuclear patterns, had no impact on prognosis. Survival, according to tumor cell types, showed that serous papillary, clear cell and the high-grade endometrioid carcinomas had the worst prognosis compared to low-grade endometrioid carcinomas, but interestingly, within this tumor group, those having high-SLS counts had a much worse survival rate than those that did not. It is concluded that an assessment of autophagic activity, particularly in the form of SLS, is useful for evaluating tumor aggressiveness and, in the absence or an excess of SLS, it may also prove valid for differentiating grade 1 endometrioid adenocarcinomas from their precursor lesions.     

A canine cancer-gene microarray for CGH analysis of tumors

As with many human cancers, canine tumors demonstrate recurrent chromosome aberrations. A detailed knowledge of such aberrations may facilitate diagnosis, prognosis and the selection of appropriate therapy. Following recent advances made in human genomics, we are developing a DNA microarray for the domestic dog, to be used in the detection and characterization of copy number changes in canine tumors. As a proof of principle, we have developed a small-scale microarray comprising 87 canine BAC clones. The array is composed of 26 clones selected from a panel of 24 canine cancer genes, representing 18 chromosomes, and an additional set of clones representing dog chromosomes 11, 13, 14 and 31. These chromosomes were shown previously to be commonly aberrant in canine multicentric malignant lymphoma. Clones representing the sex chromosomes were also included. We outline the principles of canine microarray development, and present data obtained from microarray analysis of three canine lymphoma cases previously characterized using conventional cytogenetic techniques.     

Chromosome study of five cancers of the prostate

Summary Nonrandom chromosome changes were sought in direct preparations of tumour material from the primary site of four carcinomas and one leiomyosarcoma of the prostate. Two of the carcinomas had previously received oestrogen therapy. A deleted chromosome 10, del(10)(q24), was found in all four carcinomas and may represent a specific marker in prostatic carcinoma. Three of the carcinomas also had a deleted chromosome 7, del(7)(q22), while the fourth had a 7p+. Deleted chromosomes 7 and 10 were not identified among the markers present in the leiomyosarcoma. All five tumours contained one or more abnormal chromosomes derived from chromosome 1. A Y chromosome was present in the leiomyosarcoma but in none of the carcinomas.     

Prognostic significance of ploidy level in human tumours. II extra-uterine cancers and summary of data on 1171 tumours.

The 5-year survival rate of 78 patients with carcinoma of the ovary showed that the prognosis was significantly better when the tumour modal DNA value was in the diploid region than when it was near-triploid or above. Similar data on 140 patients with carcinoma of the breast and 52 with carcinoma of the bladder also suggested a better prognosis for the near-diploid tumours. Among 105 carcinomas of the large bowel, however, there were more survivors in the high-ploidy than in the near-diploid group, although the difference was not statistically significant. The varying relationship between ploidy and prognosis, depending on the site or histological type of the tumour, is briefly discussed on the basis of the 1171 cases included in the present and a previous paper.     

P63在子宫内膜样腺癌的表达及意义

目的检测正常子宫内膜、子宫内膜增生症和子宫内膜样腺癌（endometriod adenocarcinoma,EC）组织中P63的表达,探讨P63与子宫内膜样腺癌发生、发展及预后的关系。方法采用免疫组化SP法检测正常子宫内膜（20例）,子宫内膜增生症（20例）,子宫内膜样腺癌（50例）组织中P63蛋白的表达。结果（1）正常子宫内膜中仅1例增生期内膜中有P63表达,阳性细胞零星分布于极个别腺体的基底部。子宫内膜增生症和子宫内膜样腺癌组织中,P63阳性细胞常相对集中分布于某一区域的腺体或实性巢,染色强。（2）EC组和子宫内膜增生症组P63的阳性率分别为46％和50％,与正常子宫内膜组（5．0％）比较差异有显著性护〈0．05）。子宫内膜增生症组P63的阳性率与EC组比较差异无显著性（P〉0．05）。（3）P63的表达与EC的分化程度无关（P〉0．05）。结论（1）EC组织中P63阳性细胞可能来源于胚胎时期的未分化细胞,具有多向分化的潜能。（2）P63与EC的发生发展有关,可能起癌基因的作用。（3）P63在子宫内膜增生症组织中高表达,表明P63与子宫内膜的异常增生相关。     

Satellite DNA hypomethylation vs. overall genomic hypomethylation in ovarian epithelial tumors of different malignant potential

Rearrangements in heterochromatin in the vicinity of the centromeres of chromosomes 1 and 16 are frequent in many types of cancer, including ovarian epithelial carcinomas. Satellite 2 DNA is the main sequence in the unusually long heterochromatin region adjacent to the centromere of each of these chromosomes. Rearrangements in these regions and hypomethylation of satellite 2 DNA are a characteristic feature of patients with a rare recessive genetic disease, ICF (immunodeficiency, centromeric region instability, and facial anomalies). In all normal tissues of postnatal somatic origin, satellite 2 DNA is highly methylated. We examined satellite 2 DNA methylation in ovarian tumors of different malignant potential, namely, ovarian cystadenomas, low malignant potential (LMP) tumors, and epithelial carcinomas. Most of the carcinomas and LMP tumors exhibited hypomethylation in satellite 2 DNA of both chromosomes 1 and 16. A comparison of methylation of these sequences in the three types of ovarian neoplasms demonstrated that there was a statistically significant correlation between the extent of this satellite DNA hypomethylation and the degree of malignancy (P<0.01). Also, there was a statistically significant association (P<0.005) between genome-wide hypomethylation and undermethylation of satellite 2 DNA among these 17 tumors. In addition, we found abnormal hypomethylation of satellite alpha DNA in the centromere of chromosome 1 in many of these tumors. Our findings are consistent with the hypothesis that one of the ways that genome-wide hypomethylation facilitates tumor development is that it often includes satellite hypomethylation which might predispose cells to structural and numerical chromosomal aberrations. Several of the proteins that bind to pericentromeric heterochromatin are known to be sensitive to the methylation status of their target sequences and so could be among the sensors for detecting abnormal demethylation and mediating effects on chromosome structure and stability.     

Intratumor heterogeneity of chromosome 1, 7, 17, and 18 aneusomies obtained by FISH and association with flow cytometric DNA index in human colorectal adenocarcinomas

BACKGROUND: The origin and evolution of somatic chromosome aberrations in colorectal cancer is still poorly understood. The data in the literature suggest that some specific chromosome aberrations are more common. It is not known, however, if there is a correlation of these with near-diploid and high aneuploidy previously proposed to be a characteristic of the adenoma-carcinoma sequence. METHODS: Chromosome 1, 7, 17 and 18 numerical aberrations and 1p deletions were evaluated by fluorescence in situ hybridization analysis for 20 human sporadic colorectal adenocarcinomas in 70 distinct tumor sectors and correlated with flow cytometric DNA index (DI) values. RESULTS: Aneusomy for at least one of the investigated chromosomes was observed in 60 of 70 tumor sectors corresponding to 19 of 20 adenocarcinomas (95%). Deletions at 1p, observed in 8 of 18 adenocarcinomas (44%), were intratumor homogeneous in 7 of 8 tumors. In contrast, the other aberrations were intratumor heterogeneous. Aneusomies of chromosomes 1, 7, and 17 were strongly associated with DNA high aneuploidy (DI > or = 1.4), whereas aneusomy of chromosome 18 and 1p deletions were equally common among DNA diploid and near-diploid tumors (DI < 1.4 and DI not equal to 1). CONCLUSIONS: Overall, these data suggest the existence of different aneuploidization routes correlated with specific chromosome aberrations. In addition, intratumor homogeneity of 1p deletions appears to be an indication of early occurrence or strong selection. We also suggest that tumors with monosomies and in particular monosomies-trisomies for the same chromosomes support a model of aneuploidization and chromosome instability during the colorectal tumor progression based on loss of symmetry during chromosome segregation (Giaretti: Lab Invest 71:904-910, 1994).     

Effects of tamoxifen on the endometrium and its mechanism of carcinogenicity

This study was conducted to clarify the clinicopathological characteristics of tamoxifen-associated endometrial carcinomas and its mechanisms of carcinogenesis. Seven patients with tamoxifen-associated endometrial carcinomas (TAM group) and 28 with sporadic endometrioid adenocarcinomas (EMC group) were included in the study. The clinicopathological factors, such as FIGO stage, histological type, grade, lymph node metastases, vascular invasion and the coexistence of hyperplasia, were investigated in both groups. The protein expression of p53, PTEN, hMLH1 and hMSH2 was investigated by immunohistochemistry. Microsatellite instability (MSI), k-ras and p53 mutation were also examined. In the TAM group, the histological types included five endometrioid, one endometrioid combined with serous and one clear cell type. The rates of coexistence with hyperplasia (five of seven cases) and vascular invasion (four cases) were significantly higher in the TAM group. The rates of stage III/IV (four cases) and lymph node metastasis (three cases) tended to be higher in the TAM group. Although there were no significant differences in PTEN, hMLH1 and hMSH2 expression between the two groups, p53 mutation was more frequent in three out of five cases (60%) in the TAM group compared with 2 of 15 cases in the EMC group (13.3%). No significant differences were observed concerning MSI and k-ras mutation in either group. These results suggested that TAM-associated endometrial carcinomas have overlapping biological characteristics of type I and type II endometrial carcinomas. This might explain the somewhat worse prognosis of these tumors than sporadic endometrioid carcinomas.     

Loss of heterozygosity at chromosomal regions 3p and 13q in non-small-cell carcinoma of the lung represents low-frequency events

It was recently reported that loss of heterozygosity occurred at the chromosomal region 3p in small-cell as well as in non-small-cell carcinoma of the lung. A recent report also indicated genetic changes involving sequences on chromosomes 13q and 17p in small-cell and in non-small-cell carcinomas. In the present study normal and tumor DNAs representing mostly adeno-and squamous cell carcinomas of the lung were examined for loss of heterozygosity on chromosomes 3p, 13q, 11p, and 1p. With the exception of two non-small-cell carcinomas which demonstrated loss of alleles on chromosome 3p and one small-cell carcinoma which demonstrated loss of heterozygosity at chromosome 3p as well as at 13q, evidence for loss of alleles on chromosomes 3p, 13q, 11p, and 1p could not be obtained in greater than 75% of the non-small-cell carcinoma DNAs tested. Given this result it appears unlikely that a recessive gene is located on either chromosome 3p or 13q in the majority of non-small-cell carcinomas of the lung.     

Microsatellite instability.

Unlike aneuploidy, considered to be the cardinal feature of malignant tumors ever since the chromosomal analysis of neoplastic cells became technically feasible, a second pathway toward malignancy has emerged over the past decade that is not characterized by gross aneuploidy but, instead, by inactivation of the DNA mismatch repair system, leading to a hypermutable state in which simple repetitive DNA sequences are unstable during DNA replication. Although mutations of many of these microsatellite sequences are presumably innocuous, because they do not occur in the coding or regulatory regions of genes, other such sequences are critically located in the coding regions of genes involved in the regulation of cell growth. First discovered in the rather uncommon hereditary nonpolyposis colorectal cancer syndrome, where there is an inactivating germline mutation in one of the DNA mismatch repair genes and most of the tumors show microsatellite instability, the latter phenomenon has since been implicated in about 15% of sporadic colorectal cancers, as well as in cancers at several other sites, such as the endometrium. Tumors showing microsatellite instability are generally near-diploid, are at a low stage of development, have a favorable prognosis, and, in the colon, are commonly located on the right side. In recent years, epigenetic phenomena, including hypermethylation and loss of imprinting, have come to be recognized as having a significant bearing on the development of these tumors.     

Mechanisms of aneuploidy induction in human oogenesis and early embryogenesis

The mechanisms of aneuploidy induction in human oogenesis mainly involve nondisjunction arising during the first and second meiotic divisions. Nondisjunction equally affects both whole chromosomes and chromatids, in the latter case it is facilitated by "predivision" or precocious centromere division. Karyotyping and CGH studies show an excess of hypohaploidy, which is confirmed in studies of preimplantation embryos, providing evidence in favour of anaphase lag as a mechanism. Preferential involvement of the smaller autosomes has been clearly shown but the largest chromosomes are also abnormal in many cases. Overall, the rate of chromosomal imbalance in oocytes from women aged between 30 and 35 has been estimated at 11% from recent karyotyping data but accruing CGH results suggest that the true figure should be considerably higher. Clear evidence has been obtained in favour of germinal or gonadal mosaicism as a predisposing factor. Constitutional aneuploidy in embryos is most frequent for chromosomes 22, 16, 21 and 15; least frequently involved are chromosomes 14, X and Y, and 6. However, embryos of women under 37 are far more likely to be affected by mosaic aneuploidy, which is present in over 50% of 3-day-old embryos. There are two main types, diploid/aneuploid and chaotic mosaics. Chaotic mosaics arise independently of maternal age and may be related to centrosome anomalies and hence of male origin. Aneuploid mosaics most commonly arise by chromosome loss, followed by chromosome gain and least frequently by mitotic nondisjunction. All may be related to maternal age as well as to lack of specific gene products in the embryo. Partial aneuploidy as a result of chromosome breakage affects a minimum of 10% of embryos.     

The frequency of aneuploidy among individual chromosomes in 6,821 human sperm chromosome complements

The human sperm/hamster egg fusion technique has been used to analyse 6,821 human sperm chromosome complements from 98 men to determine if all chromosomes are equally likely to be involved in aneuploid events or if some chromosomes are particularly susceptible to nondisjunction. The frequency of hypohaploidy and hyperhaploidy was compared among different chromosome groups and individual chromosomes. In general, hypohaploid sperm complements were more frequent than hyperhaploid complements. The distribution of chromosome loss in the hypohaploid complements indicated that significantly fewer of the large chromosomes and significantly more of the small chromosomes were lost, suggesting that technical loss predominantly affects small chromosomes. Among the autosomes, the observed frequency of hyperhaploid sperm equalled the expected frequency (assuming an equal frequency of nondisjunction for all chromosomes) for all chromosome groups. Among individual autosomes, only chromosome 9 showed an increased frequency of hyperhaploidy. The sex chromosomes also showed a significant increase in the frequency of hyperhaploidy. These results are consistent with studies of spontaneous abortions and liveborns demonstrating that aneuploidy for the sex chromosomes is caused by paternal meiotic error more commonly than aneuploidy for the autosomes.