Trisomy 8 as a recurrent clonal abnormality in breast cancer?

Induction of genomic instability and activation of autophagy in artificial human aneuploid cells

Chromosome missegregation can lead to a change in chromosome number known as aneuploidy. Although aneuploidy is a known hallmark of cancer cells, the various mechanisms by which altered gene and/or DNA copy number facilitate tumorigenesis remain unclear. To understand the effect of aneuploidy occurring in non-tumorigenic human breast epithelial cells, we generated clones harboring artificial aneuploidy using microcell-mediated chromosome transfer. Our results demonstrate that clones with artificial aneuploidy of chromosome 8 or chromosome 22 both show inhibited proliferation and genomic instability. Also, the increased autophagy was observed in the artificially aneuploidy clones, and inhibition of autophagy resulted in increased genomic instability and DNA damage. In addition, the intracellular levels of reactive oxygen species were up-regulated in the artificially aneuploid clones, and inhibition of autophagy further increased the production of reactive oxygen species. Together, these results suggest that even a single extraneous chromosome can induce genomic instability, and that autophagy triggered by aneuploidy-induced stress is a mechanism to protect cells bearing abnormal chromosome number.

Polysomy 13 in a canine prostate carcinoma underlining its significance in the development of prostate cancer

The dog is a well-accepted model for prostate cancer in man because of the striking similarities between both species with respect to the clinical course of the disease as well as to its similar histopathology. Cytogenetic investigations of human prostate cancers has revealed the frequent occurrence of trisomies 7, 8, and 17. In this report, we present a case of prostate carcinoma in a dog characterized by polysomy 13 as the sole cytogenetic abnormality. Along with the known homology between canine chromosome 13 and human chromosome 8 these findings suggest that a homologous area on both chromosomes plays a crucial role in subsets of prostate cancer in both species.

Comparative genomic hybridization analysis of thymic neuroendocrine tumors

Thymic neuroendocrine (carcinoid) tumors are a rare neoplasm of the anterior mediastinum. The tumors frequently exhibit a wide spectrum of histology and appear to follow a more aggressive behavior than their nonthymic counterparts. Given the differing clinicopathologic manifestations, thymic neuroendocrine tumors may also possess different cytogenetic abnormalities from those that occur in foregut carcinoid tumors. In this study, we employed comparative genomic hybridization to detect genomic instability in 10 sporadic thymic neuroendocrine tumors and one multiple endocrine neoplasia type 1 (MEN1)-associated case. Gross chromosomal imbalances were found in nine cases, including gains of chromosomal material on regions X, 8, 18 and 20p and losses on 3, 6, 9q, 13q and 11q. We did not observe deletion at locus 11q13 where the MEN1 gene is located. These findings were essentially dissimilar to those reported in sporadic and MEN1-associated foregut carcinoid tumors. Consequently, we consider that a distinctive cytogenetic mechanism is at work in the development of thymic neuroendocrine tumors, which is different from that of foregut carcinoid tumors.

Allelic imbalance of 8p indicates poor survival in gastric cancer

Gastric cancer is a common tumor worldwide and a tremendous health burden. However, the underlying mechanisms of tumorigenesis in this cancer's development are primarily undefined. Allelic imbalance (AI) of 8p has been reported in many cancers, yet, the target(s) of alteration and the importance of allelic imbalance on this chromosomal arm in gastric carcinoma development remained to be characterized. Our findings confirmed a high rate of AI on 8p in gastric cancers. Moreover, we demonstrated that AI on 8p, either overall or at marker D8S560, was associated with poorer survival in patients with gastric cancer. Finally, gastric cancers with a high rate of microsatellite instability were significantly associated with noncardia tumors and with female gender.

Molecular cytogenetic analysis of breast cancer: a combined multicolor fluorescence in situ hybridization and G-banding study of uncultured tumor cells

In six patients with breast cancer, uncultured tumor cells were investigated with G-banding and multicolor fluorescence in situ hybridization (M-FISH). A large number of numerical and structural aberrations could be analyzed. Among other structural abnormalities, reciprocal, hidden and complex translocations were found. Recurrent t(1;10) and t(6;16), not previously described, were identified, as well as t(15;22). The latter was also found in additional cases among our unpublished breast carcinomas. The significance of t(15;22) for breast cancer is discussed, taking into account also data drawn from the literature. Reciprocal translocations were a prominent feature in a pseudodiploid lobular carcinoma. Hidden translocations on 6p22-p24 were detected with M-FISH. Involvement of 6p22-p24 was observed in five cases. The analysis of various other translocations and different structural abnormalities revealed the following common breakpoints (according to frequency of involvement): 1p34-p36, 3p12-p13, 4p13-->q11, 14p11-->q11, 1q42, 8p11, 8q24, 10q22, 11q13, 11q23-q24, 13q13, and 18p10-p11. Loss of 3p and 1p34-p36-->pter and complete or partial loss of 13q and chromosome 17 were also found. With the combination of G-banding and M-FISH techniques, chromosome misclassification is avoided and the characterization of complex tumor karyotypes is more effective.

Abnormal chromosome 8 copy number in cytological smears from breast carcinomas detected by means of fluorescence in situ hybridization (FISH)

Numerical change in chromosome 8 is an acquired abnormality associated with high clinical stage and may be involved in the conversion of carcinoma in situ in the breast to invasive carcinoma. Fine needle aspiration smears from 53 cases of breast carcinoma were hybridized with centromeric probes for chromosome 8 and the X chromosome. Thirty-eight cases revealed chromosome 8 copy gain. Of the 45 grade II and III tumours, 28 showed polysomy (>3 signals) and six showed trisomy. Of the eight grade I tumours, four were trisomic, none were polysomic. There were only two cases of chromosome 8 copy loss (one each of grade I and III). X chromosome polysomy was also a frequent finding although the signal counts were similar to those for chromosome 8 in only a few cases. Chromosome 8 polysomy occurs frequently in breast carcinoma and high copy number (>3) is associated with high malignancy grade.

Genetic alteration of chromosome 8 is a common feature of human mammary epithelial cell lines transformed in vitro with benzo[a]pyrene

While some epidemiological risk factors for breast cancer have been identified, the environmental factors responsible for transformation of mammary epithelial cells are not clear. We have exposed the spontaneously immortalized human mammary epithelial cell line MCF-10A to benzo[a]pyrene and selected transformed clones based on a loss of contact inhibition and anchorage-dependent growth. Cytogenetic studies showed that each of the transformed sublines possess an isochromosome 8q aberration. The c-Myc proto-oncogene, which is positioned at 8q24, was analyzed for changes in expression. Both c-Myc mRNA and protein levels were increased in the transformed clones relative to the parental cells. The transformed clones were not able to grow as tumors in vivo when injected into nude or SCID mice. To determine whether the involvement of chromosome 8 in BP-induced mutagenesis was a reproducible event, transformed clones were selected from three additional independently treated sets of BP-exposed MCF-10A cultures and analyzed by spectral karyotyping (SKY). These transformed sublines also harbored the isochromosome 8q abnormality. Data from this model show that benzo[a]pyrene, a ubiquitous procarcinogen, can induce selectable morphologic changes in a human mammary epithelial cell line, and that these transformed cells possess chromosomal aberrations frequently found in human breast tumors.

A malignant triton tumor with an unbalanced translocation (1;13)(q10;q10) and an isochromosome (8)(q10) as the sole karyotypic abnormalities

The karyotype of a malignant nerve sheath tumor with rhabdomyosarcomatous differentiation (malignant triton tumor) of a 58-year-old woman is reported. The tumor revealed an isochromosome for the long arm of chromosome 8 and an unbalanced translocation (1;13)(q10;q10) leading to a gain of the long arm of chromosome 1 as the sole karyotypic abnormalities.

Multiple polysomies in breast carcinomas: preferential gain of chromosomes 1, 5, 6, 7, 12, 16, 17, 18, and 19

Chromosome G-banding analysis of metaphase cells from 16 primary breast carcinomas revealed the presence of multiple polysomies in near-diploid as well as in polyploid cells. Chromosome 17 was preferentially gained in 7 tumors, followed in frequency by chromosomes 1, 12, and 19 (5 tumors each), and chromosomes 5, 6, 7, 16, and 18 (4 tumors each). Eleven of the 16 carcinomas had, apart from the clones exhibiting the numerical gains, other unrelated clones. Nine of these 11 cases had clones with structural chromosome aberrations, 5 of which had structural aberrations involving the short arm of chromosome 3. The biologic significance, if any, of this seemingly nonrandom coexistence of multiple polysomies with structural aberrations of 3p is at present not known. The pattern of numerical chromosome aberrations observed in the present study is comparable to previous results from fluorescence in situ hybridization (FISH) studies, with the use of centromeric probes on interphase cells. However, unlike FISH studies, which have been focused on chromosomes 1, 3, 7, 8, 11, 16, and 17, the cytogenetic results reveal that other chromosomes also may be nonrandomly gained as part of multiple polysomies in breast carcinomas. In addition, the tumors with multiple polysomies were generally of high histologic grade and with metastasis to axillary lymph nodes, suggesting that multiple wholechromosome gains may be a pathway of genetic evolution or progression or both in some breast carcinomas.

c-myc and chromosome 8 centromere studies of ovarian cancer by interphase FISH

Forty tumor specimens from patients with ovarian cancer were studied for amplification of the c-myc oncogene relative to chromosome 8 centromere number using dual-color FISH. Interphase cytogenetic analysis showed amplification of the c-myc oncogene in 40% (16/40) of tumors using the standard oncogene:centromere ratio method of analysis. Eleven of these showed moderate amplification of c-myc, and 5 samples showed high amplification. Eight of the sixteen (50%) amplified tumors were polysomic centromere 8 as were 14 of the 24 (58%) non-amplified tumors. In previously reported work with these samples, the oncogene HER-2/neu, the chromosome 17 centromere, and the tumor suppressor gene p53 had been studied. When using the standard oncogene:centromere ratio criteria, 5 samples had amplification of both the c-myc and the HER-2/neu oncogenes, 5 samples had HER-2/neu amplification but not c-myc, 11 samples had c-myc amplification but not HER-2/neu, and 19 samples had neither oncogene amplified. The p53 gene was found to be deleted in 22.5% (9/40) of samples. The loss of the p53 gene did not appear to have any clinical correlation. The presence of an extra centromere 8 also did not appear to have any clinical correlation. The Kaplan-Meier survival curve for those patients who have c-myc amplification, while not statistically significant, appears to show a trend toward poorer survival. The survival curve for patients whose tumors have HER-2/neu amplification shows no clinical significance. It is of great interest, however, that the Kaplan-Meier plot of survival for patients whose tumors have amplification of both c-myc and HER-2/neu shows a significant difference (P = 0.047). The median survival times of the doubly amplified patient group and the non-doubly amplified groups were 12 and 43 months, respectively. This is the first study of the oncogene c-myc using FISH. The results suggest that the amplification of c-myc may indicate a poorer patient survival and that the amplification of both c-myc and HER-2/neu in combination may be a better prognostic indicator of poor patient survival.

Frequent multiplication of chromosomal region 8q24.1 associated with aggressive histologic types of breast cancers

Carcinogenesis is considered to be a multi-step process that may involve cumulative genetic alterations. One such alteration, gain of chromosomal material, has the potential for activating genes that promote carcinogenesis in breast tissues. Using 14 polymorphic microsatellite markers on the long arm of chromosome 8 (8q), we examined 142 sporadic breast cancers for abnormalities in the copy-numbers of these loci. At each locus examined, a 2- to 3-fold increase in intensities of bands representing single alleles was observed in 57 (40%) of the tumors, indicating that 'multiplication' of the DNA sequence had occurred on 8q. A 16-cM region on 8q24.1 was commonly multiplied among the tumors with partial multiplications. Multiplication on 8q24.1 was observed more frequently in invasive solid-tubular or scirrhous tumors (48/92, 52%) than in less aggressive histologic types (7/25, 28%, P = 0.031). Thus, multiplication of tumor-promoting gene(s) located on 8q24.1 may play a role in the development and/or progression of a substantial proportion of primary breast cancers, particularly those of the invasive histology.

Cytogenetic changes in benign proliferative and nonproliferative lesions of the breast

Cytogenetic analysis of short-term cultures from 69 cases of fibrocystic breast changes and 10 samples of normal mammary tissue revealed clonal chromosome aberrations in six fibrocystic lesions. All the histologically normal tissue samples had a normal karyotype. The frequency of cytogenetically abnormal cases seems to correlate with the degree of histopathologic changes of the tissue; nonproliferative lesions may have clonal chromosome alterations, but at a low frequency. Whether women with karyotypically altered fibrocystic "disease" have a higher risk of developing invasive breast cancer, compared with women without microscopically visible genetic anomalies in fibrocystic lesions, remains unknown.

Cytogenetics of benign breast lesions

This review summarizes the cytogenetic information on benign breast lesions of various histologies, i.e., fibrocystic lesions from women with and without a known hereditary predisposition to breast cancer, fibroadenomas, phyllodes tumors, and papillomas, and relate the chromosomal features with those in breast carcinoma. In general, the frequency of chromosome abnormalities is lower in benign lesions than in breast cancer, and seems to correlate with the histologic features of the tissue, and the corresponding risk of developing invasive mammary carcinoma; aberrations are more common in proliferative than in nonproliferative lesions. The karyotypes are generally less complex than those detected in invasive carcinoma, and more often involve balanced rearrangements. No lesion-specific aberration has so far been detected; on the contrary, changes repeatedly encountered in breast cancer samples can be found in benign lesions as well, e.g., gain of 1q, interstitial deletion of 3p, and trisomies 7, 18, and 20. Especially intriguing is the prevalence of rearrangements of the short arm of chromosome 3, with the minimally deleted bands 3p13-14, in proliferative lesions from prophylactic mastectomies in breast cancer families. The potential tumor suppressor gene(s) in this region remains, however, to be identified.

Two cases of fibrocystic breast disease with polysomy 18 as the sole clonal cytogenetic abnormality

In the present study, we describe the occurrence of numerical alterations of chromosome 18 in two cases of benign fibrous/fibrocystic tumors of the breast, both of which were studied by conventional cytogenetic investigations and one of which was additionally tested by fluorescence in situ hybridization with the use of an alphoid centromeric probe specific for chromosome 18. Case 1 showed a tetrasomy 18 in 2 of 33 metaphases as the only clonal chromosomal aberration. Case 2 revealed both trisomy and tetrasomy 18 as clonal alterations in metaphases and interphase nuclei.

Cytogenetic evaluation of 20 primary breast carcinomas

Chromosome analysis was performed on samples from 20 Brazilian patients with breast cancer. All the samples were from untreated patients who presented the clinical symptoms for months or years before surgical intervention. Six cases showed axillary lymph node metastases. Clonal chromosome abnormalities were detected in all cases. The numerical alterations most frequently observed involved the loss of chromosomes X, 19, 20, and 22 followed by gain of chromosomes 9 and 8. Among the structural anomalies observed, there was preferential involvement of chromosomes 11, 6, 1, 7, 3, and 12, supporting previous reports that these chromosomes may harbour genes of importance in the development of breast tumors. Two cases with a family history of breast cancer had in common total or partial trisomy 1.

A subset of gestational trophoblastic disease characterized by abnormal chromosome 8 copy number detected by fluorescence in situ hybridization

The present paper describes the results of research conducted to ascertain whether the report by Mark et al. [1], describing the concurrence of congenital trisomy 8 mosaicism and gestational trophoblastic disease (GTD) in a 42 year-old Gravida IV, Para IV patient was an isolated event. In contrast to other cases described in the literature, the patient described in Mark et al. [1] had no additional confounding chromosomal abnormalities other than trisomy 8. To the best of our knowledge, ours was the only reported case of constitutional trisomy 8 mosaicism associated with gestational trophoblastic disease, a rare gynecological disease entity. The question arises whether there exists a subset of patients with GTD characterized by an abnormal chromosome 8 copy number. The implicit hypothesis is that an abnormal number of chromosome 8 somehow predisposes to cancer. A pilot study of 10 cases of GTD was conducted using fluorescence in situ hybridization (FISH) and a commercial chromosome 8-specific alpha-satellite probe on formalin-fixed, paraffin-embedded patient tissues. Among eight informative cases successfully completed, two cases (25%) were found to be trisomic, when a cut-off point of 10% trisomic cells is adopted. Another two cases (25%) were found to be triploid. The results of our FISH study indicated that an abnormal chromosome 8 copy number found in Mark et al. [1] is unlikely to be an isolated event. Our data are consistent with the hypothesis that a subset of GTD indeed may exist which is characterized by more than two copies of chromosome 8. The present findings corroborate those recently found in breast, prostate, and other cancers.

Fluorescence in situ hybridization assessment of chromosome 8 copy number in stage I and stage II infiltrating ductal carcinoma of the breast

A total of 34 cases of infiltrating ductal carcinoma of the breast, not otherwise specified (NOS), were selected, based on the clinical stage of the disease (17 cases stage I and 17 cases stage II). The histologic grade and the DNA content of each tumor were evaluated. Each specimen was analyzed and blinded cytogenetically for the frequency of chromosome 8 copy number using fluorescence in situ hybridization (FISH). Among the informative samples, 16 cases were disomic (47%) and 18 cases (53%) were trisomic. Of the 16 disomic tumors, 13 cases (81%) were classified clinically as stage I disease and 3 cases (19%) were stage II disease. Of the 18 trisomic tumors, 4 cases (22%) were stage I, and 14 cases (78%) were stage II. Microscopically, all trisomic tumors were of high histologic grade and aneuploid when analyzed by flow cytometry. We inferred from these data that a subset of infiltrating ductal carcinomas (NOS) is characterized by chromosome 8 trisomy. This chromosomal abnormality correlates well with other markers that predicate aggressive biological behavior of the tumor. While this observation needs to be further extended, the data suggest that chromosome 8 copy number may be used as a possible marker to identify a subgroup of patients with infiltrating ductal carcinoma associated with a poor prognosis.

A subgroup of breast carcinomas is cytogenetically characterized by trisomy 12

Chromosome analysis of short-term cultured breast carcinoma cells revealed trisomy 12 in four cases. In one tumor it was the only abnormality. The second case showed cytogenetic polyclonality, but the mainline had +12 as the sole change. In the remaining two tumors, trisomy 12 was part of more complex karyotypes. These findings, especially when coupled with similar information on previously published cases, show that gain of chromosome 12 is a recurrent and sometimes early event in breast carcinogenesis.

Case of extra pulmonary, pleuro-pulmonary blastoma in a child: pathological and cytogenetic findings

We report the cytogenetic findings in a case of Pleuro-Pulmonary Blastoma of Childhood Type II. This is a rare intrathoracic tumour that can occur in the lungs with up to 25% of cases being extra pulmonary.

A fibroadenoma with a t(4;12) (q27;q15) affecting the HMGI-C gene, a member of the high mobility group protein gene family

An intracanalicular fibroadenoma of the breast showing a clonal chromosomal aberration t(4;12) (q27;q15) as the sole cytogenetic abnormality is described. In order to narrow down the breakpoint region on chromosome 12 on the molecular level we performed fluorescence in situ hybridization (FISH) analysis with a cosmid pool originating from a YAC-contig overspanning part of the region 12q14-15. We were able to narrow down the breakpoint to an approximately 230kb fragment belonging to the HMGI-C gene which maps within an area recently designated as MAR (Multiple Aberration Region). The chromosomal breakpoints of other frequent benign solid tumors, i.e. lipomas, uterine leiomyomas, and pleomorphic adenomas are clustered within the third intron of that gene.

Review of allelic loss and gain in prostate cancer

There are three nearly ubiquitous genomic "imbalances" in prostate cancer cells: 1) loss of sequences from the short arm of chromosomes 8, 2) loss of sequences from the long arm of chromosome 13q, and 3) gain of sequences on the long arm of chromosome 8, particularly in advanced disease. Candidate tumor suppressor genes and oncogenes affected by this trio of consistent changes include the c-myc gene on chromosome 8q24, the RB gene at 13q14, and potentially multiple novel genes on the short arm of chromosome 8, with a gene located more proximally potentially involved in tumor initiation and a gene or genes located more distally involved in tumor progression. Loss of regions of chromosomes 2q, 5q, 6q, 7p and 7q, 9p, 10p and 10q, 16q, 17p and 17q, and 18q, and gain of regions of 1q, 2p, 3p and 3q, 7p and 7q, 11p, 17q, and Xq have also been detected in the range of 25-50% of tumors studied. Analysis of candidate tumor suppressor genes in these regions is still in its early stages. Similarly, potential oncogenes on a series of chromosomal arms which undergo frequent amplification remain essentially uncharacterized. The basic outline of the chromosomal aberrations in prostate cancer has been well established; the details of the story remain to be filled in. This paper reviews the advantages and disadvantages of various techniques for detection of genomic loss and gain in prostate cancer cells, and reviews published reports of loss and gain in prostate cancer, focusing primarily on reports using microsatellite analysis, Southern analysis, and comparative genomic hybridization. Fluorescence in situ hybridization (FISH) based analyses of selected regions are also reviewed.

Fluorescent in situ hybridization assessment of chromosome 8 copy number in breast cancer

Conventional cytogenetics of breast and other solid tumors has been hampered by a number of factors. An analysis of breast tumor tissues was therefore undertaken using fluorescent in situ hybridization (FISH). A total of 34 specimens were analyzed using a chromosome 8-specific alpha-satellite probe. Various approaches were tested and compared. Among 30 informative samples, 11 infiltrating ductal carcinomas, not otherwise specified (NOS), 5 ductal carcinomas in situ, 5 lobular carcinomas, 3 papillary carcinomas, and 6 benign lesions were studied. Of the 11 cases of infiltrating ductal carcinomas (NOS) analyzed, four cases showed 3 signals, one case showed 4 signals, and the rest showed 2 signals. Of the 5 cases of ductal carcinoma in situ samples, 1 showed 3 signals and the other 4 cases showed 2 signals. All cases of lobular carcinomas, papillary carcinomas, and benign lesions showed 2 signals. We inferred from these data that 36% of the infiltrating ductal carcinomas (NOS) were trisomic and 9% were tetrasomic, whereas 20% of the ductal carcinomas in situ were trisomic. All samples from lobular carcinomas, papillary carcinomas, and the benign lesions were disomic. From our preliminary data, it can further be concluded that a subset of breast cancer is characterized by chromosome 8 trisomy. These data are consistent with an ever-increasing database on the association of chromosomal 8 trisomy with other cancers such as leukemia, lymphoma, prostate cancer, ovarian carcinoma, salivary gland tumor, malignant melanoma, desmoid tumors, and recently gestational trophoblastic disease. It is also noted that the ability to analyze formalin-fixed, paraffin-embedded archival material will enable a more comprehensive cytogenetic study of breast cancer than is currently available.

Observation of a deletion of the long arm of chromosome 6 in benign fibrocystic disease of the breast constitutes a challenging problem

We observed an interstitial deletion of the long arm of chromosome 6 occurring as the sole anomaly in a benign fibrocystic disease of the breast, confirming its nonrandom occurrence in this type of condition, and we discuss the possible meaning of this observation.

Significance of clonal chromosome aberrations in breast fibroadenomas

Despite the high frequency of fibroadenomas of the breast, cytogenetic results are relatively limited. We describe our cytogenetic findings in 30 fibroadenomas. Of these, three showed clonal chromosome abnormalities, i.e., 46,XX,der(6)t(1;6)(q25;p21.3); 48,XX,del(6)(q21),r(11)(?),der(14)t(6;14)(q21;q32),+2mar; and 47,XX,+5.

Cytogenetic studies of breast carcinomas: different karyotypic profiles detected by direct harvesting and short-term culture

Chromosome analysis was performed on samples from 85 consecutive patients with breast cancer by one or more of three different methods: direct harvest, culture after mechanical disaggregation, and culture after collagenase digestion. Metaphases suitable for karyotyping were obtained in 70% of the cases; direct harvest yielded metaphases in 29% and cultures without and with digestion in 40% and 59%, respectively. Chromosomal abnormalities were detected in 37 cases. Cells judged to be phenotypically abnormal in culture were twice as likely to reveal chromosomal aberrations as normal-looking cells. Eight cases showed multiclonal abnormalities. Significant differences were detected in the karyotypic profile depending on the method used. With direct harvest, the yield of complex chromosomal changes was 87%, compared to 44% after culture of digested tissue (P < 0.01), and also polyploidy was more common in direct-harvested samples. Detailed karyotypic analysis was possible in 29 primary tumors. The chromosomes most frequently involved were 1, 3, 7, 11, 16, and 17. Recurrent structural abnormalities were der(1;16)(q10;p10), i(1)(q10), del(6)(q21), and del(1)(p22). Breakpoints clustered to the centromere regions of chromosomes 1, 3, 11, 15, and 16 and to the short arms of chromosomes 7, 17, and 19. Seven of twenty-nine fully analyzed cases had a family history of breast cancer, and changes of chromosomes 1, 3, and 15 seemed to be more common in these cases. There was an association between karyotype and survival: The 3 year survival was 63% in patients with complex karyotypic changes and 92% in those without complex changes.

Loss of heterozygosity from the short arm of chromosome 8 is an early event in breast cancers

Loss of heterozygosity (LOH) from the short arm of chromosome 8 (8p) is common to many human carcinomas, including those of the colon and prostate. It localizes to two discrete regions, 8p21 and 8p22. This suggests the presence of at least two tumor suppressor genes (TSGs) on this chromosome arm. Human breast cancers show consistent 8p deletions in cytogenetic studies, chromosome 8 aneusomy and isochromosome 8q, indicating that the relevant gene(s) may play a role, but the results of molecular analyses of chromosome 8 in breast cancer have been variable. We present here data for 8p LOH in an unselected series of human breast cancers with the use of three CA-repeat markers that showed high rates of LOH in other tumors. All cases were informative for at least one marker, and LOH was seen in 11 of 20 cases (55%). LOH was more frequent for the 8p22 markers D8S254 and D8S133 than for NEFL in 8p21. Regional metastases of the tumors showed allele profiles identical to those of their primaries regardless of whether there was LOH or retention of alleles. One case of microsatellite instability (RER+) was seen. LOH did not correlate with receptor status, ploidy, percentage of cells in S phase, or tumor size: We observed LOH at equal rates in small (< 2 cm) and in larger (> 2 cm) tumors. The data suggest that LOH from 8p is frequent in human breast cancers and that loss of the putative 8p TSG may be an important event in early stage breast cancer.

Cytogenetics and molecular genetics of human solid tumours

It is generally accepted that cancer is a genetic disease resulting from the accumulation of multiple genomic rearrangements. These rearrangements involve gross chromosomal abnormalities (e.g. translocations and deletions) as well as submicroscopic mutations affecting both oncogenes and tumour suppressor genes. Recent studies of several tumour specific translocations in sarcomas have shown that the translocations result in so-called fusion genes. In this review we will discuss the specificity and implications of different genetic alterations in both sporadic and hereditary human solid tumours, and provide examples of how these changes can be used as tumour specific markers of both diagnostic and prognostic significance.

Cytogenetic report of a male breast cancer

The cytogenetic findings on G-banding in an infiltrating ductal breast carcinoma in a 69-year-old man are reported. The main abnormalities observed were trisomy of chromosomes 8 and 9 and structural rearrangement in the long arm of chromosome 17 (add(17)(q25)). Our results confirm the trisomy of chromosome 8 in the characterization of the subtype of ductal breast carcinomas and demonstrate that chromosome 17, which is frequently involved in female breast cancers, is also responsible for the development or progression of primary breast cancers in males.

Trisomy 8 in alveolar soft part sarcoma

Cytogenetic studies were performed on an alveolar soft part sarcoma of a 6-year-old boy. An extra chromosome 8 was present in 26 of 28 metaphases analyzed.

Trisomy 8 and 18 as frequent clonal and single-cell aberrations in 185 primary breast carcinomas

For cytogenetic investigations short-term cultures of 185 breast carcinomas (135 invasive ductal, 21 invasive lobular, 12 invasive ductal with intraductal components, seven heterogeneous, six intraductal, four invasive ductal and lobular) were prepared. Cytogenetic examinations revealed clonal abnormalities in 39 cases with a predominance of simple numerical chromosome changes, i.e., trisomies of chromosomes 7, 8, and 18. One hundred forty-six tumors did not show clonal abnormalities, but single-cell aberrations other than monosomies occurred in 79 of these tumors. Compared to cells of epithelial hyperplasia of the breast, amniotic fluid cells, and cells from pleomorphic adenomas cultivated using the same medium, the frequency of single-cell trisomies was significantly higher. Trisomy 8 was not only found as a clonal aberration in 10 cases but was also the most frequent non-clonal aberration. Trisomy 7 and 18 were also frequent clonal as well as non-clonal cytogenetic deviations.

Chromosome analysis of 97 primary breast carcinomas: identification of eight karyotypic subgroups

Chromosome banding analysis of 97 short-term cultured primary breast carcinomas revealed clonal aberrations in 79 tumors, whereas 18 were karyotypically normal. In 34 of the 79 tumors with abnormalities, two to eight clones per case were detected; unrelated clones were present in 27 (34%) cases, whereas only related clones were found in seven. These findings indicate that a substantial proportion of breast carcinomas are of polyclonal origin. Altogether eight abnormalities were repeatedly identified both as sole chromosomal anomalies and as part of more complex karyotypes: the structural rearrangements i(1)(q10), der(1:16)(q10;p10), del(1)(q11-12), del(3)(p12-13p14-21), and del(6)(q21-22) and the numerical aberrations +7, +18, and +20. At least one of these changes was found in 41 (52%) of the karyotypically abnormal tumors. They identify a minimum number of cytogenetic subgroups in breast cancer and are likely to represent primary chromosome anomalies in this type of neoplasia. Other candidates for such a role are translocations of 3p12-13 and 4q21 with various partner chromosomes and inversions of chromosome 7, which also were seen repeatedly. Additional chromosomal aberrations that give the impression of occurring nonrandomly in breast carcinomas include structural rearrangements leading to partial monosomies for 1p, 8p, 11p, 11q, 15p, 17p, 19p, and 19q and losses of one copy of chromosomes X, 8, 9, 13, 14, 17, and 22. The latter changes were seen consistently only in complex karyotypes, however, and we therefore interpret them as being secondary anomalies acquired during clonal evolution.

Chromosome abnormalities in benign hyperproliferative disorders of epithelial and stromal breast tissue

Cytogenetic analysis of short-term cultures from 15 cases of benign proliferative breast disease (PBD), 10 diffuse PBD and 5 papillomas, and 15 fibroadenomas of the breast revealed clonal chromosome abnormalities in 7 diffuse PBD lesions, 4 papillomas and 5 fibroadenomas. The remaining 14 cases had a normal female chromosome complement. Cytogenetically unrelated abnormal clones were seen in 4 fibroadenomas and 2 PBDs. A single abnormal clone was found in 9 PBDs and 1 fibroadenoma. Three clonal abnormalities were seen as recurrent changes in 6 cases, namely interstitial deletions of 3p with 3p 12-14 as the minimally common deleted segment (in 1 papilloma, 1 diffuse PBD with atypia and 1 mixed-pattern lesion with both papilloma and atypical diffuse PBD features), r(9)(p24q34) (in 1 diffuse PBD and 1 fibroadenoma), and del(1)(q12)(again in 1 diffuse PBD and 1 fibroadenoma). Intriguingly, 6 of the 16 abnormal cases had chromosome changes that have been seen repeatedly as primary abnormalities in breast carcinomas: der(16)t(1;16)(q10;p10), del(3)(p12p14), and del(1)(q12). We conclude that some of the chromosome anomalies frequently found in breast carcinomas are also present in PBD and fibroadenomas. These aberrations may be accepted as early, neoplasia-relevant mutations. However, they do not seem to be sufficient by themselves to unleash a malignant process.

Aneuploidy for chromosome 1 and overall DNA content in benign and malignant breast disease

Fluorescence in situ hybridization (FISH) with a probe for the pericentromeric region of chromosome 1 and DNA content measurements by image-analysis-based densitometry have been carried out on imprints of benign and malignant breast tissue. In general, an increase in the number of spots per nucleus was observed in the invasive carcinomas, with a large intercellular variation. In comparison with lymphocytes from controls, some cases of benign breast disease already had an increased frequency of aneusomy of chromosome 1, although they were all (near)diploid by DNA-content. However, an overall concordance between the DNA content measurements and the results of FISH was observed, although some exceptions were seen. A statistically significant correlation between the DNA index and the mean number of spots for chromosome 1 per nucleus was found. A linear discriminant analysis was applied on the data; the resulting classification of patients was most accurate when parameters describing DNA content and FISH results were combined.

Chromosomal aneuploidy in proliferative breast disease

Although some forms of proliferative breast disease have been associated with increased risk of breast cancer, substantial confirmatory evidence that the lesions are biologically premalignant has not been presented. Our intent was to identify cytogenetic aberrations in proliferative breast disease using fluorescence in situ hybridization probes selected for their relationship to aberrations previously reported in breast cancer. Application of fluorescence in situ hybridization techniques to paraffin tissue sections using pericentromeric probes for chromosomes 1, 16, 17, 18, and X revealed chromosome aneuploidy in proliferative and malignant lesions of the breast. Sectioning artifact that may result in nuclear truncation was controlled by establishing expected baseline frequencies for gain and loss in normal tissues from the same breast. Localization of chromosomal aberrations to proliferative breast disease lesions with concomitant retention of a normal chromosome complement in corresponding normal breast tissues indicates biologic significance of the results. The similarities of losses involving chromosomes 16, 17, and 18 in hyperplastic lesions and in malignant breast lesions suggest that some hyperplasias may be part of a sequence of progression to malignancy in breast cancer. Gains of chromosome 1 in both in situ and invasive carcinoma are consistent with reports of polysomy 1q as a common cytogenetic change in breast cancer. Its localization to advanced lesions suggests that this trisomy is probably not the initial cytogenetic change in breast cancer tumorigenesis.

Two human breast tumors with translocations involving 12q13-15 as the sole cytogenetic abnormality

Two benign epithelial breast lesions showing clonal chromosomal alterations involving 12q13-15 are reported. As the only clonal aberration a t(12;14)(q13-14;q24) was noted in a florid epithelial hyperplasia with extended adenosis. A t(10;12)(p14-15;q13) was found in a papilloma also with areas of florid epithelial hyperplasia.