Primary carcinoma of the fallopian tube: comparative genomic hybridization reveals high genetic instability and a specific, recurring pattern of chromosomal aberrations.

Primary fallopian tube carcinoma (PFTC) is a rare and highly aggressive tumor. Twelve cases of PFTC (stages IA to IV) were analyzed by comparative genomic hybridization. The most consistent DNA gain was mapped to chromosome arm 3q in 11 of 12 cases. In six cases, the gain of 3q was present as a high level copy number increase (amplification) with a consensus region mapped to 3q26.2-qter. In the 12 cases, other frequent gains were located on chromosome arms 1q (in 11 cases), 2q (in 10), 7q (in 9), 8q (in 9), 5p (in 8), 6p (in 7), 12p (in 7), and 14q (in 6). Frequent copy number losses occurred on chromosome arms 16q (in 8 cases), 22q (in7), 6q (in 6). 8p (in 6), 18q (in 6), Xq (in 6), 1p (in 5), and 17p (in 5). All chromosomes were involved in chromosomal aberrations and the average number of copy alterations per case was 19.7. None of the 12 carcinomas revealed the presence of human papillomavirus (HPV) genomes. All of the cases exhibited crude aneuploidy. Strong p53 immunoreactivity could be observed in 10 of 12 cases while p21/WAF1 expression was low or undetectable. These results indicate that PFTC is a genomically highly unstable cancer, an observation that is in agreement with the poor prognosis associated with this tumor. A high frequency of 3q-gains has also been observed in HPV-related carcinomas of the uterine cervix. However, none of the PFTC was HPV related, suggesting that the 3q-gain is independent from HPV DNA.

Stromelysin-3 mRNA expression in dysplasias and invasive epithelial cancer of the larynx.

Matrix metalloproteinases are believed to play an important role in tumor progression, invasion and metastasis. In order to investigate if the expression of stromelysin-3 (ST3) mRNA could add prognostic information concerning invasive laryngeal cancer and/or be indicative of a high risk for tumor progression in laryngeal dysplasias ST3 expression was analyzed by in situ hybridisation of formalin fixed paraffin embedded laryngeal specimens. Furthermore, all specimens underwent image cytometry (ICM) DNA analysis, and, p53 immunostaining. Invasive epithelial cancer, both localized (T1, T2) cancers, cured, as well as not cured, by radiotherapy, and cases with regional lymph node metastases were studied. Furthermore, high grade and low grade dysplasias, selected for rapid, slow and non-progression, as well as non-neoplastic inflammatory lesions were investigated. Expression of the ST3 gene was found in 9 out of 14 (64%) invasive cancer lesions, and in 3 out of 10 (30%) dysplasias, thus indicating that ST3 expression correlates to tumor progression. The ST3 positive laryngeal cancer lesions displayed a higher degree of DNA aberration than the ST3 negative lesions thus suggesting that ST3 positivity could indicate highly malignant tumors. Of the three ST3 positive dysplasias, the first progressed rapidly to cancer in situ with suspected microinvasion. The second ST3 positive dysplasia progressed to invasive cancer within five months. The third ST3 positive dysplasia had been radically excised and hereby cured. All but one of the dysplastic lesions showed p53 immunoreactivity, and all dysplasias exhibited aneuploid cells. ST3 expression appears to be a late event in the multistage process of carcinogenesis and could prove useful as an indicator of dysplasias with imminent risk for progression to invasive cancer.

Advanced-stage cervical carcinomas are defined by a recurrent pattern of chromosomal aberrations revealing high genetic instability and a consistent gain of chromosome arm 3q.

We have analyzed 30 cases of advanced-stage cervical squamous cell carcinoma (stages IIb-IV) by comparative genomic hybridization (CGH). The most consistent chromosomal gain in the aneuploid tumors was mapped to chromosome arm 3q in 77% of the cases. Acquisition of genetic material also occurred frequently on Iq (47%), 5p (30%), 6p (27%), and 20 (23%). Recurrent losses were mapped on 2q (33%), 3p (50%), 4 (33%), 8p (23%), and 13q (27%). High-level copy number increases were mapped to chromosome 8, chromosome arms 3q, 5p, 8q, 12p, 14q, 17q, 19q, 20p, and 20q, and chromosomal bands 3q26-27, 9p23-24, 11q22-23, and 12p13. In the majority of the cases, the presence of high-risk human papilloma virus genomes was detected. High proliferative activity was accompanied by crude aneuploidy. Increased p21/WAF-I activity, but low or undetectable expression of TP53 were representative for the immunophenotype. This study confirms the importance of a gain of chromosome arm 3q in cervical carcinogenesis and identifies additional, recurrent chromosomal aberrations that are required for progression from stage I tumors to advanced-stage carcinomas.

A recurrent pattern of chromosomal aberrations and immunophenotypic appearance defines anal squamous cell carcinomas.

Squamous cell carcinomas of the anus are rare neoplasias that account for about 3% of large bowel tumours. Infections with human papillomaviruses are frequently detected in these cancers, suggesting that pathogenic pathways in anal carcinomas and in carcinomas of the uterine cervix are similar. Little is known regarding recurrent chromosomal aberrations in this subgroup of squamous cell carcinomas. We have applied comparative genomic hybridization to identify chromosomal gains and losses in 23 cases of anal carcinomas. A non-random copy number increase of chromosomes 17 and 19, and chromosome arm 3q was observed. Consistent losses were mapped to chromosome arms 4p, 11q, 13q and 18q. A majority of the tumours were aneuploid, and most of them showed increased proliferative activity as determined by staining for Ki-67 antigen. p53 expression was low or undetectable, and expression of p21/WAF-1 was increased in most tumours. Sixteen cancers were satisfactorily tested for the presence of HPV by consensus L1-primer polymerase chain reaction; nine were HPV positive, of which eight were positive for HPV 16.

Tumor cytogenetics revisited: comparative genomic hybridization and spectral karyotyping.

Fluorescence in situ hybridization techniques allow the visualization and localization of DNA target sequences on the chromosomal and cellular level and have evolved as exceedingly valuable tools in basic chromosome research and cytogenetic diagnostics. Recent advances in molecular cytogenetic approaches, namely comparative genomic hybridization and spectral karyotyping, now allow tumor genomes to be surveyed for chromosomal aberrations in a single experiment and permit identification of tumor-specific chromosomal aberrations with unprecedented accuracy. Comparative genomic hybridization utilizes the hybridization of differentially labeled tumor and reference DNA to generate a map of DNA copy number changes in tumor genomes. Comparative genomic hybridization is an ideal tool for analyzing chromosomal imbalances in archived tumor material and for examining possible correlations between these findings and tumor phenotypes. Spectral karyotyping is based on the simultaneous hybridization of differentially labeled chromosome painting probes (24 in human), followed by spectral imaging that allows the unique display of all human (and other species) chromosomes in different colors. Spectral karyotyping greatly facilitates the characterization of numerical and structural chromosomal aberrations, therefore improving karyotype analysis considerably. We review these new molecular cytogenetic concepts, describe applications of comparative genomic hybridization and spectral karyotyping for the visualization of chromosomal aberrations as they relate to human malignancies and animal models thereof, and provide evidence that fluorescence in situ hybridization has developed as a robust and reliable technique which justifies its translation to cytogenetic diagnostics.

Comparative genomic hybridization reveals a specific pattern of chromosomal gains and losses during the genesis of colorectal tumors.

Comparative genomic hybridization was used to screen the DNA extracted from histologically defined tissue sections from consecutive stages of colorectal carcinogenesis for chromosomal aberrations. No aberrations were detected in normal epithelium (n = 14). Gain of chromosome 7 occurred as a single event in low-grade adenomas (n = 14). In high-grade adenomas (n = 12), and overrepresentation of chromosomes 7 and 20 was present in 30% of the cases analyzed. The transition to colon carcinomas (n = 16) was characterized by the emergence of multiple chromosomal aberrations. Chromosomes 1, 13, and 20 and chromosome arms 7p and 8q were frequently gained, whereas chromosome 4 and chromosome arms 8p and 18q were recurrently underrepresented. The same tissue sections that were used for CGH were analyzed by means of DNA-ploidy measurements and immunohistochemical staining to quantify proliferative activity and p21/WAF-1 and TP53 expression. We observed that crude aneuploidy and increased proliferative activity are early events in colorectal carcinogenesis, followed by TP53 overexpression and the acquisition of recurrent chromosomal gains and losses during the progression from high-grade adenomas to invasive carcinomas.

Diagnostic impact of nuclear DNA content and proliferative activity in benign and malignant melanocytic lesions.

Nuclear DNA content was assessed, using image cytometry, in adult melanocytes in normal skin and in 20 intradermal naevi, 60 junction naevi, 107 compound naevi, 61 dysplastic naevi, 17 melanomas in situ and 101 primary malignant melanomas. Proliferation was estimated using mitotic counting and immunohistochemical staining by anti-Ki-67 (clone MIB1) monoclonal antibodies. All normal adult melanocytes; and intradermal naevi (97% junction naevi, 98% compound naevi, 66% dysplastic naevi) were diploid. Thirty-four percent of the dysplastic naevi, 88% of the melanomas in situ and 96% of the malignant melanomas were clearly aneuploid. Proliferation, as assessed by mitotic counting and MI81 index, was significantly higher in aneuploid invasive malignant melanomas than in aneuploid dysplastic naevi (P<0.0001). The results indicate that histomorphologically defined entities of melanocytic lesions are characterized by typical DNA distribution patterns. Distinct aneuploidy combined with high proliferation rates generally seem to be well correlated to an increased malignancy potential of the lesion. In dysplastic naevi, the clonic expansion of aneuploid naevus cells may be limited by host defence mechanisms. Thus, DNA aneuploidy seems to indicate increased risk of malignant transformation, but has to be combined with other data, such as proliferation, in order to differentiate more precisely between different melanocytic lesions.

Gain of chromosome 3q defines the transition from severe dysplasia to invasive carcinoma of the uterine cervix.

We have chosen tumors of the uterine cervix as a model system to identify chromosomal aberrations that occur during carcinogenesis. A phenotype/genotype correlation was established in defined regions of archived, formalin-fixed, and hematoxylin/eosin-stained tissue sections that were dissected from normal cervical epithelium (n = 3), from mild (n = 4), moderate (n = 6), and severe dysplasias/carcinomas in situ (CIS) (n = 13), and from invasive carcinomas (n = 10) and investigated by comparative genomic hybridization. The same tissues were analyzed for DNA ploidy, proliferative activity, and the presence of human papillomavirus (HPV) sequences. The results show that an increase in proliferative activity and tetraploidization had occurred already in mildly dysplastic lesions. No recurrent chromosomal aberrations were observed in DNA extracted from normal epithelium or from mild and moderate dysplasias, indicating that the tetraploidization precedes the loss or gain of specific chromosomes. A gain of chromosome 3q became visible in one of the severe dysplasias/CIS. Notably, chromosome 3q was overrepresented in 90% of the carcinomas and was also found to have undergone a high-level copy-number increase (amplification). We therefore conclude that the gain of chromosome 3q that occurs in HPV16-infected, aneuploid cells represents a pivotal genetic aberration at the transition from severe dysplasia/CIS to invasive cervical carcinoma.

The relationship between proliferating cell nuclear antigen (PCNA), nuclear DNA content and mutant p53 during genesis of cervical carcinoma.

Proliferating cell nuclear antigen (PCNA), nuclear DNA content and mutant p53 overexpression were studied by means of image cytometry and immunohistochemistry respectively in normal mucosa (n = 10), in mild (n = 16), moderate (n = 9) and severe (n = 17) atypical lesions, as well as in squamous cell carcinomas (n = 36) of the cervix uteri. The results show that increasing histopathological atypia in the cervical mucosa was correlated to an initial increase of PCNA followed by distinct aneuploidy and p53 overexpression. The data are suggested to contribute to a better understanding of the genesis of cervical carcinoma, and to indicate that the coexistence of both distinct aneuploidy and p53 immunoreactivity can be used to decide if a cell population is neoplastic, whereas the absence of p53 overexpression does not necessarily exclude neoplasia. This diagnostic procedure can be suggested to improve early detection of intraepithelial squamous neoplasia.

Correlation between stromelysin-3 mRNA level and outcome of human breast cancer.

The expression level of stromelysin-3 (ST3) mRNA was analyzed by in situ hybridization of formalin-fixed, paraffin-embedded primary breast-tumor samples from 76 patients. Digital image analysis of the dark-field in situ hybridization signal was used to measure the maximal level of ST3 expression in each tumor. All 55 invasive ductal carcinomas and 9 of 10 invasive lobular carcinomas were positive for ST3. Invasive tumors had significantly higher levels of ST3 than in situ tumors. Furthermore, ST3 levels were higher in invasive ductal carcinomas than in invasive lobular carcinomas. The ST3 expression level was significantly correlated to fatal metastatic disease (mean follow-up 104 months). ST3 levels of < 2,500 units were associated with distant metastasis in 46% of patients, whereas levels of > 2,500 units were associated with metastasis in 79% of patients selected for study. ST3 mRNA levels did not correlate with tumor size, microvessel density, DNA ploidy or estrogen-receptor levels. Studies of ST3 expression may provide information valuable for the understanding of breast cancer biology and for prognosis.

DNA ploidy in human colorectal adenomas.

The DNA content of 101 colorectal adenomas of various histologic types resected from 83 patients was determined by image cytometric measurements in order to investigate if a correlation between DNA ploidy and particular histomorphologic features exists and if DNA measurements can be of additional diagnostic value. Overall, 67 of 101 (66%) adenomas showed an aneuploid DNA distribution pattern, including 8 of 19 (42.1%) mildly atypical, 32 of 48 (66.7%) moderately atypical and 27 of 34 (79.4%) severely atypical adenomas. Correlating DNA content with the histologic type, 17 of 42 (40.5%) tubular, 28 of 37 (75.7%) tubulovillous and all 22 villous adenomas exhibited aneuploid DNA histograms. Aneuploidy was also observed more frequently in larger adenomas. The results show a good correlation between tumor size, histomorphologic features and DNA content. The most remarkable observation is that as many as 42% of the adenomas histomorphologically considered mildly atypical exhibited aneuploidy. Since aneuploidy has been demonstrated to indicate premalignant or malignant cellular alterations, DNA image cytometry is suggested for providing valuable additional information on the diagnosis of colorectal adenomas.

The relationship between aneuploidy and p53 overexpression during genesis of colorectal adenocarcinoma.

This paper describes the investigation of nuclear DNA content and p53 immunoreactivity in normal mucosa (n = 25), mildly (n = 15), moderately (n = 28) and severely atypical (n = 22) colorectal adenomas and in colorectal adenocarcinomas (n = 116). Twenty-seven per cent of the mildly atypical, 43% of the moderately, 77% of the severely atypical adenomas and 91% of the colorectal carcinomas were distinctly aneuploid. In the aneuploid lesions p53 immunoreactivity was not observed in mildly atypical adenomas, whereas 17% of the moderately atypical, 24% of the severely atypical adenomas and 66% of the adenocarcinomas were p53 positive. None of the diploid lesions were p53 immunoreactive. These data are interpreted to indicate that genomic instability as reflected by crude aneuploidy occurs early during genesis of colorectal carcinoma and represents a high risk factor for p53-gene mutation.

DNA content and PCNA immunoreactivity in oral precancerous and cancerous lesions.

Thirty-three dysplastic lesions showing varying degrees of atypia located in the oral cavity and 83 squamous cell carcinomas located in the oral cavity and tongue (n = 56) or in the lips (n = 27) were analysed by means of proliferating cell nuclear antigen (PCNA) immunoreactivity and image cytometric DNA measurements. The results show that in dysplastic lesions increasing cellular atypia correlated to elevated proliferative activity and aneuploidy occurring in the basal cell layers. In highly differentiated squamous carcinomas increased PCNA immunoreactivity and aneuploidy was preferentially observed focally (grade 1 tumours) or in the invasive zones (grade 2 tumours). In contrast, more poorly differentiated carcinomas (grade 3 and 4 tumours) showed strongly elevated proliferative activity and aneuploidy throughout the entire tumour mass.

DNA ploidy in human colorectal adenocarcinomas.

Image cytometric determination of DNA content was performed on 207 colorectal adenocarcinomas surgically resected from 205 patients. Of these 207 tumors, 193 (93.2%) showed an aneuploid DNA distribution pattern, whereas the remaining 14 (6.8%) exhibited a DNA pattern corresponding to that found in proliferating diploid populations. The DNA content of 20 of these colorectal carcinomas was also studied by flow cytometric measurements on deparaffinized, disintegrated material. Flow cytometric measurement detected aneuploidy in only 9 of these 20 (45%) tumors, whereas 17 of the same 20 (85%) carcinomas showed aneuploidy when using image cytometric measurement on imprints. These results suggest that colorectal carcinomas are either aneuploid (vast majority) or proliferating diploid and that image cytometric DNA measurement on histologically controlled material is superior to flow cytometric measurement.