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Biomedical subjects

H Höfler

Publications and source records attributed to H Höfler.

At least 73 records · Page 4Linked to original sources
PubMed2000

Chromosomal imbalances in Barrett's adenocarcinoma and the metaplasia-dysplasia-carcinoma sequence.

To characterize cytogenetic alterations found in Barrett's adenocarcinoma (BA) and, more importantly, its premalignant stages, we studied chromosomal imbalances in various lesions in the histologically proposed metaplasia-dysplasia-carcinoma sequence using comparative genomic hybridization (CGH). Using 30 esophageal adenocarcinoma resection specimens, we were able to study 30 areas of Barrett's adenocarcinoma and 8 lymph node metastases (LN). In addition, we investigated 25 premalignant lesions adjacent to BA derived from a subset of 14 resection specimens including 11 areas of high grade dysplasia (HGD), 8 areas of low grade dysplasia (LGD), and 6 areas of intestinal metaplasia (IM), which were laser-microdissected and studied with CGH. To validate the CGH findings, fluorescence in situ hybridization analysis on 13 BA with probes specific for HER-2/neu and 20q13.2 were performed. The chromosomal alterations most often identified in BA were: gains on 8q (80%), 20q (60%), 2p, 7p and 10q (47% each), 6p (37%), 15q (33%) and 17q (30%). Losses were observed predominantly on the Y-chromosome (76%), 4q (50%), 5q and 9p (43% each), 18q (40%), 7q (33%) and 14q (30%). High-level amplifications were observed on 8q23-qter, 8p12-pter, 7p11-p14, 7q21-31, 17q11-q23. Recurrent chromosomal changes were also identified in metaplastic (gains on 8q, 6p, 10q, losses on 13q, Y, 9p) and dysplastic epithelium (gains on 8q, 20q, 2p, 10q, 15q, losses on Y, 5q, 9p, 13q, 18q). Novel amplified chromosomal regions on chromosomes 2p and 10q were detected in both Barrett's adenocarcinoma and premalignant lesions. An increase of the average number of detected chromosomal imbalances from IM (7.0 +/- 1.7), to LGD (10.8 +/- 2.2), HGD (13.4 +/- 1.1), BA (13.3 +/- 1.4), and LN (22 +/- 1.2) was seen. Although the detection of common chromosomal alterations in premalignant lesions and adjacent carcinomas suggest a process of clonal expansion, the occurrence of several chromosomal changes in an apparently random order relative to one another is striking evidence that clonal evolution is more complex than would be predicted by linear models. This is probably a reflection of the existence of many divergent neoplastic subpopulations and highlights one of the main problems associated with surveillance of Barrett's patients, namely sampling error.

Adenocarcinoma↗
PubMed2000

Molecular genetic changes in metastatic primary Barrett's adenocarcinoma and related lymph node metastases: comparison with nonmetastatic Barrett's adenocarcinoma.

Lymph node metastasis is one of the strongest negative prognostic factors for patients with Barrett's adenocarcinoma (BCA). However, despite the importance of the metastatic process in BCA, the molecular basis of it remains poorly understood. To search for cytogenetic events associated with metastasis in regional or distant lymph nodes in BCA, we investigated 8 primary BCA and their lymph node metastases and compared them with 18 nonmetastatic BCA. In metastatic primary BCA, we observed significantly more DNA gains on 3q (P = .013), 17q (P = .019), and 22q (P = .021) compared with nonmetastatic primary BCA. No statistically significant correlation could be observed between DNA copy number changes and the histopathologic stage, grade, or survival (P > .05). The most frequent alteration observed only in lymph node metastases but not in the related primary tumor was loss of 2q (5 of 8). Coamplification of 7p and chromosome 17 was found in 6 of 8 lymph node metastases. A comparison of DNA copy number changes between primary tumors and their corresponding metastases indicated a high degree of genetic heterogeneity. Fluorescence in situ hybridization analysis demonstrated the involvement of the Her-2/neu gene in primary BCA and its related lymph node metastases. Each of the investigated primary tumors and related lymph node metastases also showed striking heterogeneity with respect to Her-2/neu, with several areas displaying different levels of amplification. In summary, our data indicate that DNA copy number changes on 2q, 3q, 7p, 17q, and 22q may be involved in the metastatic process in BCA. Furthermore, the striking genetic heterogeneity that we found between primary BCA and its lymph node metastases may underlie BCA's poor responsiveness to therapy and could help explain why prognostic biomarkers measured exclusively in primary tumors give an incomplete view of the biologic potential of BCA.

Adenocarcinoma↗
PubMed2000

Fibrovascular esophageal polyp as a diagnostic challenge.

Fibrovascular polyps are rare benign esophageal tumors that usually arise from the proximal third of the esophagus. We present the case of a 48-year-old man with a history of dysphagia and 7-kg weight loss over a period of 2 months. A barium swallow showed a distended esophagus with a tumor extending from the upper esophageal sphincter to the cardia. On a thoracic computed tomographic scan, a homogeneous intramural mass with a density of 22 Hounsfield units was seen, which extended throughout the entire esophagus. Fiberoptic endoscopy confirmed the presence an intramural tumor beginning at the upper esophageal sphincter and reaching to the cardia. The tumor was completely covered with mucosa, except for an ulcerated area at its distal end, which herniated into the stomach. On endoscopic ultrasound, the tumor appeared to grow submucosally and to respect the muscularis propria. Endoscopic biopsies from the ulcerated distal aspect of the tumor suggested a leiomyoma. None of the imaging modalities used revealed evidence of a polyp or intraluminal esophageal tumor. Rather, a potentially malignant extensive intramural tumor was suspected, and an esophagectomy was performed. Only at the time of removal of the specimen did it become evident that the tumor mass was located intraluminally with a pedicle in the region of the upper esophageal sphincter. The final pathological diagnosis was a giant fibrovascular polyp of the esophagus.

Diagnostic Imaging↗
PubMed2000

Stromelysin-3 expression in noninvasive and invasive neoplasms of the urinary bladder.

Stromelysin-3 (ST-3) is a protease frequently expressed by fibroblasts surrounding invasive carcinomas. Based on its expression in some cases of breast carcinoma-in-situ, it has been thought to indicate a higher likelihood for subsequent invasion in preinvasive lesions. Carcinoma-in-situ (pTis) and noninvasive papillary tumor (pTa) of the urinary bladder are preinvasive lesions with an uncertain potential to become invasive. We studied the expression of ST-3 in pTis, pTa, and invasive bladder tumors to see whether it had an association with any established histopathologic variables and whether its expression might be an indicator of incipient invasion in the preinvasive lesions. Twenty-seven pTis, 27 pTa tumors, and 56 invasive bladder carcinomas were studied for ST-3 expression with immunohistochemistry and, in selected cases, with in situ hybridization. Staining for ST-3 was evaluated semiquantitatively. None of 27 pTis lesions, 4 of 27 pTa tumors, and 41 of 56 (73.2%) invasive carcinomas were positive for ST-3. Statistically significant associations were found in the invasive carcinomas between ST-3 expression and lymphatic vessel invasion, an infiltrative invasive pattern, and invasion into at least the muscle layer (pT2,3,4 v pT1). The expression of ST-3 in frankly invasive tumors was associated with a more aggressive tumor phenotype. Its expression in a small subgroup of pTa lesions may be indirect evidence that some tumors diagnosed as pTa have invasive potential.

Aged↗
PubMed2000

Gene rearrangement and Chernobyl related thyroid cancers.

The increase in thyroid carcinoma post-Chernobyl has been largely confined to a specific subtype of papillary carcinoma (solid/follicular). This subtype is observed predominantly in children under 10 in unirradiated populations, but maintains a high frequency in those aged 10-15 from those areas exposed to fallout from the Chernobyl accident. The aim of this study was to link morphology with molecular biology. We examined 106 papillary carcinomas from children under the age of 15 at operation. All were examined for rearrangements of the RET oncogene by reverse transcription polymerase chain reaction (RT-PCR); a subset of these cases were also examined for mutations of the three ras oncogenes, exon 10 of the thyroid stimulating hormone receptor, associated more usually with a follicular rather than papillary morphology, and exons 5, 6, 7 and 8 of the p53 gene, commonly involved in undifferentiated thyroid carcinoma. Rearrangements of the REToncogene were found in 44% of papillary carcinomas in which we studied fresh material; none of the tumours examined showed mutation in any of the other genes. The two rearrangements resulting from inversion of part of chromosome 10 (PTC1 and PTC3) accounted for the majority of RET rearrangements identified, with PTC1 being associated with papillary carcinomas of the classic and diffuse sclerosing variants and PTC3 with the solid/follicular variant.

Adolescent↗
PubMed2000

Increasing chromosome 1 copy number parallels histological progression in breast carcinogenesis.

Chromosome 1 copy number in the benign breast lesions hyperplasia and atypical duct hyperplasia (ADH) was investigated using fluorescence in situ hybridization on paraffin sections. Progression of chromosome 1 changes occurring in parallel with histological progression from normal through hyperplasia and ADH to ductal carcinoma in situ (DCIS) and invasive carcinoma was also assessed, both overall and within individual patients. The mean signal number for normal cells was 1.14, while that for hyperplasia was 1.56 and ADH was 1.5, while values for DCIS of 1.95 and invasive duct carcinoma of 1.79, were higher (P < 0.001). Six of the seven cases also showed a significant trend towards an increasing proportion of cells with greater than 2 signals per nucleus occurring with histological progression (P < 0.001). These results support the concept that benign proliferative breast disease is a biological precursor of in-situ and invasive ductal carcinoma, the early histological changes possibly indicating a field effect with further genetic changes required for the development of a malignant phenotype.

Breast Neoplasms↗
PubMed2000

Endoscopic ultrasound criteria for vascular invasion in the staging of cancer of the head of the pancreas: a blind reevaluation of videotapes.

BACKGROUND: It has been claimed in several prospective studies that endoscopic ultrasonography (EUS) is highly accurate in the locoregional staging of pancreatic cancer. However, the value of the EUS criteria for the diagnosis of vascular involvement is less well established. To totally exclude potential bias introduced by the availability of prior information, a completely blinded analysis of videotapes of patients with cancer of the pancreatic head was therefore conducted. METHODS: Videotape sequences of 75 patients with cancer of the head of the pancreas with surgical confirmation or unequivocally positive angiography demonstrating vascular invasion were reevaluated without any clinical data or information from other imaging studies. Involvement of the vascular system (portal vein with confluence, superior mesenteric vein, celiac axis) was assessed on EUS with special emphasis on EUS parameters of the tumor-vessel relationship. RESULTS: The overall sensitivity and specificity of EUS in the diagnosis of venous invasion were 43% and 91%, respectively, when using predetermined parameters (visualization of tumor in the lumen, complete obstruction, or collateral vessels). If the parameter "irregular tumor-vessel relationship" had been added to these criteria, the sensitivity would have risen to 62%, but the specificity would have fallen to 79%. The only vascular system that could be properly visualized by EUS was the portal vein/confluence area. The positive and negative predictive values for the single parameters chosen to diagnose portal venous involvement were as follows: 42% and 33% for irregular tumor-vessel relationship, 36% and 34% for visualization of tumor in the vascular lumen, 80% and 28% for complete vascular obstruction, and 88% and 18% for collateral vessels. CONCLUSIONS: In a completely blinded evaluation of the EUS diagnosis of vascular invasion by cancer of the head of the pancreas it was not possible to find suitable morphologic parameters with clinically useful sensitivity and specificity values (over 80%).

Adult↗
PubMed2000

Accumulation of chromosomal imbalances from intraductal proliferative lesions to adjacent in situ and invasive ductal breast cancer.

Carcinoma of the breast is thought to evolve through a sequential progression from normal to proliferative epithelium and eventually into carcinoma. Here lumpectomy specimens from five patients were studied, selected for the presence of ductal hyperplasia without atypia, atypical ductal hyperplasia, ductal carcinoma in situ, and invasive ductal carcinoma. Laser microdissection of tissue allowed precise sampling and direct correlation of phenotypic and genotypic changes. Analyses of the samples revealed an increasing mean number of chromosomal changes occurring with increasing histologic severity, and for the first time chromosomal abnormalities were demonstrated in ductal hyperplasia without atypia. Chromosomal changes found in each of the four histologic entities included gains on 10q, 12q, 16p, and 20q and loss on 13q. In ductal hyperplasia without atypia, gain on 20q as well as loss on 13q was detected with high frequency (four of five samples). Alterations identified in more than 50% of atypical ductal hyperplasia samples included gains on 3p, 8q, 15q, and 22q and loss on 16q. In ductal carcinoma in situ, gain of DNA on 1q and 17q and loss on 4q were additionally found, and in invasive ductal carcinoma, further gains on 6p, 10q, 11q13, and 17p were identified. The chromosomal alterations occurring in the different histopathologic lesions strongly suggest that these regions harbor tumor suppressor genes or oncogenes significant for the development of ductal carcinoma of the breast.

Breast↗
PubMed2000

Tumor-associated overexpression of the soluble T1-S receptor in lymph node-negative breast cancer.

The oncogene-inducible secreted T1-S glycoprotein is overexpressed in invasive breast carcinomas in mice. As yet, nothing is known about the expression of T1-S in spontaneously occurring human cancers. A report follows on the overexpression of T1-S mRNA in 67% of primary invasive lymph node-negative breast carcinomas (31 of 46 patients) as determined by quantitative reverse transcriptase polymerase chain reaction. Overexpression of T1-S mRNA was independent of the tumor size, the histologic tumor type, and the estrogen-and progesterone-receptor status but was associated with high to moderate differentiation of the tumors (G , G2). T1-S mRNA levels were low to nondetectable in resting normal mammary tissue and benign fibrocystic disease of the breast. Immunohistochemistry confirmed a low to moderate T1 immunoreactivity in epithelial cells of resting mammary tissue and benign fibrocystic disease and highly variable levels of T1 immunoreactivity in breast carcinoma cells. Kaplan-Meier analysis of disease-free survival during a median observation period of 61 months revealed a trend toward a reduced relapse rate and an extended relapse-free survival period for T1-S mRNA--overexpressing breast carcinomas. It is concluded that overexpression of T1-S receptor in lymph node-negative breast cancer may be a potential indicator for tumors with a low metastatic potential.

Adult↗
PubMed2000

Heterogeneous chromosomal aberrations in intraductal breast lesions adjacent to invasive carcinoma.

There is evidence that breast cancer is a heterogeneous disease phenotypically as well as molecular biologically. So far, heterogeneity on the molecular biological level has not been investigated in potential precursor lesions, such as ductal hyperplasia (DH) and ductal carcinoma in situ (DCIS). In this study we applied comparative genomic hybridization (CGH) to formalin-fixed, paraffin-embedded breast tissue with DH and DCIS, adjacent to invasive ductal carcinoma (IDC), to screen these potential precursor lesions for whole genomic chromosomal imbalances. Laser-microdissection was used to select pure cell populations from the sections. Isolated DNA was amplified by degenerate oligonucleotide primed PCR (DOP-PCR) and further processed for CGH analysis. Investigating multiple samples (n = 25) from four patients we found an average of 5.6 +/- 0.9 (mean +/- SEM) chromosomal imbalances already present in DH. In the twelve DCIS lesions an average of 10.8 (+/- 0.9) aberrations was identified with 14.8 (+/- 0.8) aberrations in the four adjacent IDC lesions. The increasing number of chromosomal changes in parallel with the histopathological sequence corroborate the hypothesis, that the carcinomas may have developed through a sequential progression from normal to proliferative epithelium and eventually into carcinoma. However, heterogeneous results were identified in the multiple samples per entity from the same patient, demonstrated mainly in the DCIS samples in the chromosomal regions 6p, 9p, 11q, 16p and 17q, in the DH samples by 3p, 16p and 17q. This heterogeneous findings were most pronounced within the DH and was less in the DCIS and IDC samples. The only aberration consistently found in all samples-even in all DH sample-was amplification of the 20q13 region. Our results demonstrate, that the applied combination of laser-microdissection, DOP-PCR and CGH, may serve to analyse breast carcinogenesis pathways in suitable histological material. However, so far, it is unclear how to handle heterogeneous results and these make identification of relevant changes more difficult. Setting a threshold and evaluating only those chromosomal changes which are present in a majority of samples may be one possibility. This involves however, the risk that infrequent but possibly significant aberrations may be missed. Figures on http://www.esacp.org/acp/2000/20-1/aubele. htm.

Breast Neoplasms↗
PubMed2000

Evaluation of c-erbB-2 overexpression and Her-2/neu gene copy number heterogeneity in Barrett's adenocarcinoma.

Amplification of the Her-2/neu gene is accompanied by overexpression of its cell surface receptor product, c-erbB-2 protein. To investigate the degree of intratumoural heterogeneity we applied immunohistochemistry in primary Barrett's adenocarcinoma (BCA) (n = 6) and dysplasia adjacent to the carcinoma (n = 4). In addition, fluorescence in situ hybridisation (FISH) was performed in primary BCA (n = 5) and dysplastic areas (n = 4). For an objective evaluation digital image analysis and laser scanning microscopy were used. Five of six BCA showed a marked intratumoral heterogeneous staining pattern ranging from areas in which the tumour cells were negative or faintly positive to tumour areas with a strong staining of the entire membrane. Among the two dysplastic areas also a heterogeneous staining pattern was observed. FISH analysis revealed marked heterogeneity of intratumoral gene copy number changes in all BCA showing populations with different fractions of cells with polysomy, low level amplification and high level amplification. One dysplasia showed a minor population with Her-2/neu signal clusters. In conclusion, we observed marked intratumoural heterogeneity of c-erbB-2 protein overexpression and Her-2/neu gene copy number in the majority of the primary BCA analyzed. Digital image analysis and laser scanning microscopy were helpful in quantifying the variations in protein expression and DNA copy number in individual tumour cells. The observed heterogeneity could hamper the exact diagnostic determination of the c-erbB-2 status in small biopsies and possibly influence the effectiveness of a potential c-erbB-2 targeting therapy. Figures on http://www.esacp.org/acp/2000/20-1/walch.htm+ ++.

Adenocarcinoma↗
PubMed2000

Tumor-derived mutated E-cadherin influences beta-catenin localization and increases susceptibility to actin cytoskeletal changes induced by pervanadate.

E-cadherin participates in homophilic cell-to-cell adhesion and is localized to intercellular junctions of the adherens type. In the present study, we investigated the localization of adherens junction components in cells expressing mutant E-cadherin derivatives which had been previously cloned from diffuse-type gastric carcinoma. The mutations are in frame deletions of exons 8 or 9 and a point mutation in exon 8 and affect the extracellular domain of E-cadherin. Our findings indicate that E-cadherin mutated in exon 8 causes beta-catenin staining at lateral cell-to-cell contact sites and, in addition, abnormally located beta-catenin in the perinuclear region. Moreover, the various mutant E-cadherin derivatives increased the steady-state levels of alpha- and beta-catenin and were found in association with these catenins even after induction of tyrosine phosphorylation by pervanadate. Sustained pervanadate treatment led, however, to rounding-up of cells and induction of filopodia, changes which were first detectable in cells expressing E-cadherin mutated in exon 8. The deterioration of the cell contact was not accompanied with disassembly of the E-cadherin-catenin complex. Based on these observations, we propose a model whereby in the presence of mutant E-cadherin tyrosine phoshorylation of components of the cell adhesion complex triggers loss of cell-to-cell contact and actin cytoskeletal changes which are not caused by the disruption of the E-cadherin-catenin complex per se, but instead might be due to phosphorylation of other signaling molecules or activation of proteins involved in the regulation of the actin cytoskeleton.

Actin Cytoskeleton↗
PubMed2000

Loss of heterozygosity and microsatellite instability as predictive markers for neoadjuvant treatment in gastric carcinoma.

We analyzed a group of gastric carcinomas treated with a cisplatin-based neoadjuvant chemotherapy regimen for microsatellite instability (MSI) and loss of heterozygosity (LOH) to determine whether there is any relation between microsatellite alterations and therapy response. Pretherapeutic endoscopic biopsies of 37 patients were studied at 11 microsatellite loci. Thirteen (35%) had a complete or partial clinical response (responders), and 24 (65%) had only a minor or no response (nonresponders). High-grade MSI was found in two tumors, both nonresponders, whereas low-grade MSI was found in five biopsies, including three non-responders and two responders. Regarding LOH, the most obvious differences between the groups were observed on chromosome 17p13, the location of the p53 gene, with 7 of 12 (58%) and 3 of 20 (15%) of the informative tumors exhibiting LOH in responders and nonresponders, respectively (P = 0.018). A statistically significant difference was also observed in the fractional allelic loss (FAL) ratio of the groups. Among the 13 responding patients, 7 (54%) tumors exhibited high FAL (>0.5-0.75), 2 (15%) showed medium FAL (>0.25-0.5), and 4 (31%) demonstrated low FAL values (0-0.25), whereas among the 22 nonresponding patients, 2 (9%) tumors showed high FAL, 5 (23%) showed medium FAL, and 15 (68%) showed low FAL (P = 0.020). These data suggest that LOH at chromosome 17p13 is associated with a good clinical response to cisplatin-based chemotherapy, suggesting that altered p53 function might render cells more sensitive to therapy. Furthermore, the association of FAL with therapy response indicates that gastric carcinomas with a high level of chromosomal alteration may be more sensitive to this type of chemotherapy.

Adult↗
PubMed2000

[Morphologic response evaluation of neoadjuvant chemotherapy of gastric carcinoma].

A primary goal of the histopathologic evaluation of the gastric resection specimen is the determination of prognostically relevant factors, but it is not known whether, following neoadjuvant therapy, these factors have the same influence on prognosis. The goal of this study was to investigate prognostically relevant macroscopic and microscopic findings after neoadjuvant chemotherapy. The resection specimens of 36 patients with locally advanced gastric carcinoma who had been treated with Etoposide, Adriamycin and Cisplatin were investigated with respect to tumor size, Lauren type, ypTNM, UICC R-status, lymphangiosis, and degree of regression. On the basis of these factors, a prognosis score was developed that included both the degree of regression (grade 1-3), staging parameters (UICC T-category, R-status), tumor size and lymphatic vessel invasion. All of the parameters were weighted according to a score (1 point--best, 3 points--worst). The points were added for each individual case and the cases were divided into three prognosis groups, Group A: 5-7 points (n = 5), Group B: 8-10 points (n = 15), and Group C: > or = 11 points (n = 16). When compared with survival by the Kaplan-Meier method, these three prognosis groups showed highly significant differences (p < 0.0001). These results demonstrate that it is possible to accurately predict survival using resection specimens following neoadjuvant chemotherapy, which could lead to the identification of subgroups for which additional, further adjuvant therapy might be useful.

Adult↗
PubMed1999

Tumour-associated E-cadherin mutations alter cellular morphology, decrease cellular adhesion and increase cellular motility.

A major function of the cell-to-cell adhesion molecule E-cadherin is the maintenance of cell adhesion and tissue integrity. E-cadherin deficiency in tumours leads to changes in cell morphology and motility, so that E-cadherin is considered to be a suppressor of invasion. In this study we investigated the functional consequences of three tumour-associated gene mutations that affect the extracellular portion of E-cadherin: in-frame deletions of exons 8 or 9 and a point mutation in exon 8, as they were found in human gastric carcinomas. Human MDA-MB-435S breast carcinoma cells and mouse L fibroblasts were stably transfected with the wild-type and mutant cDNAs, and the resulting changes in localization of E-cadherin, cell morphology, strength of calcium-dependent aggregation as well as cell motility and actin cytoskeleton organization were studied. We found that cells transfected with wild-type E-cadherin showed an epitheloid morphology, while all cell lines expressing mutant E-cadherin exhibited more irregular cell shapes. Cells expressing E-cadherin mutated in exon 8 showed the most scattered appearance, whereas cells with deletion of exon 9 had an intermediate state. Mutant E-cadherins were localized to the lateral regions of cell-to-cell contact sites. Additionally, both exon 8-mutated E-cadherins showed apical and perinuclear localization, and actin filaments were drastically reduced. MDA-MB-435S cells with initial calcium-dependent cell aggregation exhibited decreased aggregation and, remarkably, increased cell motility, when mutant E-cadherin was expressed. Therefore, we conclude that these E-cadherin mutations may not simply affect cell adhesion but may act in a trans-dominant-active manner, i.e. lead to increased cell motility. Our study suggests that E-cadherin mutations affecting exons 8 or 9 are the cause of multiple morphological and functional disorders and could induce the scattered morphology and the invasive behaviour of diffuse type-gastric carcinomas.

Actins↗
PubMed1999

Intratumoral heterogeneity in breast carcinoma revealed by laser-microdissection and comparative genomic hybridization.

To evaluate the potential cytogenetic heterogeneity in breast carcinoma, several small cell groups (each consisting of 20 to 50 cells) were investigated within paraffin sections. By laser-microdissection, three to seven cell groups were taken per case. The DNA was amplified by degenerate oligonucleotide primed PCR (DOP-PCR), and the samples were analyzed by CGH for chromosomal gains and losses. Two ductal invasive breast carcinomas, one of them with two lymphnode metastases, were investigated. To compare the results from the small samples, CGH was also performed on DNA isolated from the tumorous regions of three to five serial sections (10(7) to 10(6) cells). The aberrations observed in the microdissected tumor samples were multiple and involved up to 14 different chromosomal or subchromosomal regions. The most frequent changes were gains on chromosomes 12q (14/20) and 20q (16/20), and loss on 13q (12/20). Some aberrations have rarely been detected (e.g., loss on 2p, gain on 8q). Comparing chromosomal imbalances in primary tumors and lymph node metastases, more consistent changes were found between the primary tumor and its corresponding metastases than between both primary tumors. The laser-microdissected samples in general showed more chromosomal aberrations than DNA isolated from several tumor sections. Our CGH results were confirmed by fluorescence in situ hybridization (FISH) for the chromosomal regions of centromere 1 and 20, and 20q13. In addition, microsatellite analyses on 31 samples confirmed our CGH findings for selected chromosome regions 2p and 11q. It can be concluded that there is a distinct intratumoral heterogeneity in primary breast tumors as well as in the corresponding lymph node metastases. The combination of microdissection and CGH enabled us to detect cytogenetic aberrations from important clones which are missed when analyzing DNA extracted from large cell numbers.

Breast Neoplasms↗