Interphase cytogenetic analysis of prostatic carcinomas by use of nonisotopic in situ hybridization.

To gain a better understanding of chromosomal aberrations in direct correlation with histology, we studied tumor material from 35 patients (36 regions) with primary prostate carcinoma by nonisotopic in situ hybridization. Nine biotinylated DNA probes were used on serial paraffin sections (centromer-specific probes for X, Y, 1, 7, 8, 10, 17, and 18, and a telomer-specific probe for 1p; ONCOR). Of the 324 hybridized sections, 94% were suitable for evaluation. In 34 of the 35 cases (35 of 36 regions) 1-8 chromosomal aberrations were detected. Chromosome X showed supernumerary centromer copies in 44% of cases. The probes for chromosomes 1, 1p, 10, and 18 demonstrated deletions in 25, 23, 40 and 58% of cases, respectively. Gains as well as deletions were present for Y, 7, 8, and 17 in 31, 25, 36, and 58% of cases, respectively. In 27% of cases discordant copy numbers of the centromer- and the telomer-specific probes for chromosome 1 were observed. No aberration which might be specific for prostate cancer could be established. The rate of aneusomy increased significantly with histological grade. Intratumoral heterogeneity of chromosomal aberrations was revealed in one case. Due to the higher sensitivity of nonisotopic in situ hybridization, aneusomic cases outnumbered cases with cytometrically determined DNA aneuploidy. In view of published results of metaphase preparations, the high frequency of aneusomy and some of the chromosomal aberrations detected by nonisotopic in situ hybridization were unexpected.

Her-2/neu analysis in archival tissue samples of human breast cancer: comparison of immunohistochemistry and fluorescence in situ hybridization.

PURPOSE: The objective of our study was to compare the methods used in the literature to analyze HER-2/neu status on archival breast cancer tissue. Therefore, a series of antibodies was evaluated to assess their immunohistochemical (IHC) sensitivity in correlation to gene amplification determined by fluorescence in situ hybridization (FISH). MATERIALS AND METHODS: HER-2/neu overexpression was studied on paraffin sections of 85 invasive breast cancers using a panel of five monoclonal (9G6, 3B5, CB11, TAB250, GSF-HER2) and two polyclonal antibodies (A8010, A0485) in addition to the HercepTest (DAKO, Glostrup, Denmark). HER-2/neu gene amplification was determined by FISH using a dual-color probe (PathVysion; Vysis, Stuttgart-Fasanenhof, Germany). RESULTS: HER-2/neu overexpression was demonstrated in 26% (9G6, TAB250, GSF-HER2), 27% (3B5, CB11), 33% (A8010) and 42% (A0485, HercepTest) of the tumors. FISH on paraffin sections identified gene amplification in 28% of the tumors. Strongly positive IHC results (3+) were always associated with gene amplification. Among the 16 tumors presented with weakly positive IHC results (2+) using the HercepTest, 12 (75%) lacked gene amplification. CONCLUSION: The comparison of IHC and FISH demonstrated an excellent correlation of high-level HER-2/neu overexpression (3+) with gene amplification; ie, FISH does not provide further information in these tumors. However, weakly positive IHC results (2+) obtained with the HercepTest share only a minor association with gene amplification.

Tumour size is an important predictor for the outcome after liver transplantation for hepatocellular carcinoma.

AIMS: Recently, there is a tendency to expand tumour sizes qualifying for OLT. The present study re-evaluates tumour size and histopathological features as selection criteria for OLT. METHODS: Retrospective analysis of 93 adult HCC patients underwent OLT between June 1985 and December 2003. Median follow-up was 28 months (1-222 months). The Milan criteria were routinely applied since 1994. RESULTS: Five year survival rate of HCC patients was significantly lower than in patients transplanted for benign diseases, 41 and 71%, respectively (p<0.0001). Multivariate analysis revealed that the presence of vascular invasion represents the most significant predictor (p<0.001) affecting the survival rate. Survival was also significantly impaired when the tumour size was >5 cm (p<0.05), whereas the number of nodules had no significant effect on survival. Consequently, the survival rate for HCC fulfilling the Milan criteria histologically improved to 70% since 1994. CONCLUSION: Tumour size has been shown to be the most important pre-operatively detectable predictor for patient survival after OLT.

Parathyroid localization.

Twenty-nine consecutive patients with suspected primary hyperparathyroidism were examined preoperatively using ultrasound, sonographically guided fine needle aspiration, and aspirate immunostaining for PTH. In 25 patients, localization of enlarged parathyroid glands was successful. In 2 patients, the tumors were located retrosternally and, thus, could not be detected by ultrasound. One patient had a multinodular goiter which impeded localization. In 1 patient with renal osteodystrophy, 2 enlarged parathyroid glands in the neck were not visualized preoperatively. Cytology was not diagnostic, although some cytological features were suggestive of parathyroid cells. Immunostaining of the aspirated smears for PTH, however, correctly diagnosed all preoperatively localized lesions. Ultrasound should be the routine procedure of choice for preoperative localization of abnormal parathyroid glands in primary hyperparathyroidism. Fine needle aspiration and immunocytochemistry can supply confirmation, if necessary.

P53 gene product and EGF-receptor are highly expressed in placental site trophoblastic tumor.

Immunohistochemical analysis of curettage material from a placental site trophoblastic tumor (PSTT) revealed a high expression of p53 gene products, of epidermal growth factor receptor (EGF-R) and of Ki-67 (MIB-1) proliferation associated antigen. bcl-2 was not expressed. These results show that in PSTT inactivation/dysregulation of p53 and upregulation of EGF-R and MiB-1 occurs, indicating that these factors are probably involved in tumor genesis and propagation of PSTT. The prognostic significance of the molecular genetic data, however, remains to be established.

Comparison of DNA ploidy in prostatic intraepithelial neoplasia and invasive carcinoma of the prostate: an image cytometric study.

Prostatic intraepithelial neoplasia (PIN) is regarded as the most important premalignant lesion of prostatic epithelium. The aim of this investigation was to find clues to formal pathogenesis of prostatic cancer. For this purpose DNA ploidy (determined by means of image cytometry [ICM] using 4-microns-thick Feulgen-stained paraffin sections) of PIN and invasive carcinoma was compared. Prostatic tissue of 72 patients (mean age, 67.5 years; 82 areas with carcinoma and 71 areas with PIN) was examined. In 44 cases PIN and carcinoma were coexistent in the same prostates, the PIN grade being high in 77% of these cases (P < .05). In higher-grade PIN and higher-grade carcinoma the c-values, 2.5c-exceeding-rate, and aneuploidy rate increased (P < .01). Carcinomas associated with diploid PIN (either low or high grade) showed diploidy and aneuploidy in an equal number of cases, whereas 70% of aneuploid PIN cases (all high grade) were associated with aneuploid invasive carcinomas (P < .01). Conversely, in 71% of the cases with aneuploid carcinoma the coexistent PIN (either low or high grade) was diploid. Our findings show that aneuploidy can be acquired at a preinvasive stage of carcinogenesis in the prostate and suggest that aneuploid high-grade PIN might be regarded as a precursor of some but not all aneuploid prostatic carcinomas. Image cytometry analysis seems to be a promising method for further subclassification of high-grade PIN lesions into groups with putatively lower or higher risk. However, further investigation is necessary to confirm the clinical importance of these results.

Lymphangioleiomyomatosis: recurrence after single lung transplantation.

Lymphangioleiomyomatosis (LAM) is a rare disease which afflicts young women of childbearing age. Recently, it has been listed as an indication for lung transplantation. We describe a case of recurrent LAM in a 31-year-old woman occurring in the allograft of a male donor after single lung transplantation. Nonisotopic in situ hybridization shows that the smooth muscle cell proliferation is of donor origin.

bcl-2 expression, p53 accumulation, and apoptosis in ovarian carcinomas.

Because little is known about the importance of apoptosis and its regulation in epithelial ovarian cancer, the authors looked for bcl-2 expression and p53 accumulation by immunohistochemistry in 148 ovarian carcinomas of different histologic types and stages. The number of apoptotic cells was assessed in situ by enzymatic detection of DNA fragmentation. Strong bcl-2 expression correlated with low histologic grade (P = .004) and was most often seen in endometrioid carcinomas (P = .001), whereas p53 accumulation was predominantly found in serous and undifferentiated carcinomas (P <.001) and high grade tumors (P <.001). p53 accumulation was associated with advanced tumor stage (P <.001) and the presence of residual disease after surgery (P <.001). Apoptosis increased with histologic grade (P = .012); apoptotic cells were sparse or absent in tumors of low malignant potential and mucinous carcinomas, but found in all other carcinoma types (P = .001). Apoptosis, bcl-2 expression, and p53 protein accumulation were not correlated with each other. The analysis of the postoperative course of 110 patients showed that survival depended on histologic tumor type (P = .0037), histologic grade (P = .0143), FIGO (International Federal of Gynecology and Obstetrics) stage (P = .0001), and absence or presence of postoperative residual tumor mass (P = .0001). p53 accumulation was also associated with adverse prognosis (P = .0001). However, bcl-2 positive carcinomas who had a statistically significantly better outcome than patients with p53 positive and bcl-2 negative tumors (P = .0443). Regarding FIGO stage and p53 alone in a Cox model, p53 proved to contribute additional prognostic information both in FIGO stages I/II as well as in FIGO stages III/IV. Thus, our observations point to different molecular alterations possibly underlying phenotypic diversity of ovarian carcinomas and provide clues for a better understanding of tumor progression in these neoplasms. Apoptosis plays a role in ovarian carcinomas, but seemingly is regulated in a different way than in nonneoplastic tissues.

Cellular chimerism of the lung after transplantation. An interphase cytogenetic study.

The present study evaluated the origin of endothelial and epithelial cells, as well as of lymphocytes and macrophages, after lung transplantation. Biopsy specimens from patients who underwent lung and heart-lung transplantation and received organs of sex-mismatched donors were studied by means of nonisotopic in situ hybridization with DNA probes of the X and Y chromosome. By means of monoclonal antibodies against leukocytes, T and B lymphocytes, and macrophages, the various infiltrating cell types were analyzed. In all allografted lungs, the endothelial cells and bronchial and alveolar epithelium retained the donor sex type. The lymphocytes of the donor were almost completely replaced by recipient cells 1 month after transplantation. Low numbers of alveolar macrophages of the donor were present during the entire period under study. Low numbers of donor lymphocytes and high numbers of donor alveolar macrophages in the allografted lung seem to be correlated with a worse clinical course.

The influence of p53 and associated factors on the outcome of patients with oral squamous cell carcinoma.

In several tumour entities the immunohistochemical detection of p53 has proved to be a predictive factor for the survival of the patients. In this study the effector waf1 and the regulator mdm2 responsible for the inactivation of p53 were also determined in 156 tissue samples of primary squamous cell carcinomas in the oral cavity and oropharynx, their lymph node metastases, and the epithelium outside the invasively growing tumour from 107 patients. In this latter epithelium there was a significant correlation between grade of dysplasia and staining for p53 (P<0.01). In the dysplastic epithelium a significant correlation between p53, waf1, and mdm2 was shown (P<0.05). Differences in the immunohistochemical staining between different blocks of the tumour tissue and also between primary tumours and their lymph node metastases were revealed in 11-44% of cases, but there was no correlation with other variables, such as formation of lymph node metastases. In contrast to the conventional tumour grading and staging, no influence of any of the variables determined on survival or recurrence-free survival could be detected. It seems that p53 and associated factors are important in the early stages of cancerogenesis but not in further tumour progression and metastatic spread.

Prognostic significance of apoptosis and associated factors in oral squamous cell carcinoma.

Tumour progression is characterised by an imbalance between cell proliferation and apoptosis. The aim of our study was to estimate the importance of proliferation and apoptosis associated parameters in primary squamous cell carcinomas (SCCs) of the oral cavity and oropharynx. For determination of apoptosis, the enzymatic labelling of DNA fragmentation with a terminal transferase reaction was used in 156 tissue samples of 107 patients, including corresponding lymph-node metastases in nine cases. P53, bcl-2, and Ki-67 were determined immunohistologically. P53 was detectable in 50.5% of the cases. Positive staining was associated significantly with decreased apoptosis (P<0.003). Bcl-2 was upregulated in 31.8% of the cases depending on the tumour grading (P<0.001) and correlated negatively with apoptosis (P<0.001). Proliferation (P<0.006) and apoptosis (P<0.03) were enhanced in larger tumours, though a direct correlation between these two parameters was not proven. Nevertheless, in contrast to the conventional tumour staging and grading, neither the expression of p53 or bcl-2 nor the apoptosis or Ki-67 measurements were able to predict survival or recurrence-free survival of the patients suffering from a SCC in the oral cavity or oropharynx. Our observations suggest that the function of wild-type p53 to induce apoptosis is lost in at least half of the SCCs under study and that the physiological function of bcl-2 as potent inhibitor of apoptosis is widely preserved in oral SCC.

HIV-related parotid lymphoepithelial cysts. Immunohistochemistry and 3-D reconstruction of surgical and autopsy material with special reference to formal pathogenesis.

Whether lymphoepithelial cysts in the parotid glands in HIV-infected patients develop from pre-existing salivary gland inclusions in intraparotid lymph nodes or from a lymphoepithelial lesion of salivary parenchyma is unclear. To examine their pathogenesis we performed a histological and immunohistochemical study of salivary specimens from 100 AIDS patients in different disease stages. There is a continuous morphological spectrum of changes within the salivary parenchyma, starting with lymphoid stroma infiltration and evolving to characteristic lymphoepithelial duct lesions with a immunohistochemically proven basal cell proliferation and to fully developed ductal cysts. Involvement of myoepithelial cells-postulated in comparable Sjögren-associated duct lesions-is excluded immunohistochemically. Computer-assisted 3-D reconstructions confirm an association of the cysts with the intralobular duct system. Our study disproves the prevailing hypothesis, which suggests that the lymphoid cell compartment of HIV-associated lymphoepithelial cysts stems from pre-existing intraparotid lymph nodes. The results demonstrate that a secondary lymphatic infiltration of salivary parenchyma provokes a lymphoepithelial lesion of striated ducts with basal cell hyperplasia. The frequent progression to a multifocal cystic lymphoepithelial lesion may be supported by ductal compression through a high degree of lymphofollicular hyperplasia in early disease.

Lymphoepithelial duct lesions in Sjögren-type sialadenitis.

It is not clear, whether the so-called basal cells of the salivary striated ducts are an independent cell-type distinct from myoepithelial cells, making characterization of the cell proliferation typical of the duct lesions in Sjögren-type sialadenitis/benign lymphoepithelial lesion (BLEL) difficult. An immunohistochemical investigation including different cytokeratin subtypes, alpha-actin, Ki-67 and Bcl-2 was directed at the epithelial cytoskeleton in normal parotid parenchyma (n=8), BLEL (n=12), HIV-associated lymphoepithelial cysts (n=8) and palatine tonsils (n=8). There are profound morphological and functional differences between basal and myoepithelial cells in the normal salivary duct. Development of duct lesions in BLEL arises from basal cell hyperplasia of striated ducts with aberrant differentiation into a multi-layered and reticulated epithelium, characterized by profound alteration of the cytokeratin pattern. This functionally inferior, metaplastic epithelium is similar to the lymphoepithelial crypt epithelium of palatine tonsils. The often postulated participation of myoepithelial cells in duct lesions of Sjögren disease/BLEL cannot be supported. We regard the designations lymphoepithelial lesion and lymphoepithelial metaplasia as the most appropriate.

Impairment of genomic DNA binding to a putative dysfunctional receptor on erythrocytes independent of complement and antibodies in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is characterized by a variety of autoantibodies and other immune abnormalities indicative of an immunological hyperactivity. Antibodies against native DNA, however, are a disease-specific marker and play a major role in the pathogenesis of systemic or organ-specific disease manifestations. Nevertheless, the mechanisms causing the appearance of autoantibodies and immune complexes in SLE are not yet understood. Here, we report that chromosomal DNA and other forms of nucleic acids are usually cleared from circulation by binding to a yet unidentified receptor-like protein on the surface membrane of erythrocytes, independently from complement or antibodies. The binding kinetics of DNA and other nucleic acids to erythrocytes are significantly altered in SLE patients, showing an overall reduced binding capability and presaturated binding kinetics. Significant amounts of chromosomal DNA can be isolated from erythrocytes of SLE patients but not from normal controls. Electron microscopy shows electron-dense particles on the surface of SLE erythrocytes (approximate size 20-40 nm). Comparative genomic hybridization reveals that the nucleic acid isolated from erythrocytes of SLE patients is of genomic and random origin, leading to an accumulation of "free" nucleic acids in the periphery, which eventually induces a B-cell immune response.

Extensive pulmonary haemorrhage in an Egyptian mummy.

We report on the morphological and trace element findings of several internal organs from an Egyptian mummy approximately dating from the year 950 B.C. according to 14C-analysis. By use of a multidisciplinary approach we succeeded in discovering evidence for severe and presumably recurrent pulmonary bleeding during life. This was suggested by the finding of massive haemosiderin deposits in the lung and a selectively and markedly elevated level of iron in trace element analysis of the lung tissue. Furthermore, we observed an enhanced deposition of birefringent particles in the lung tissue, without significant fibrosis. The histological analysis of liver, stomach and intestine confirmed the macroscopic organ diagnoses without evidence of any major pathological processes. In addition, analysis for various drugs revealed a significant deposition of tetrahydrocannabinol (THC), nicotine and cocaine in several organs of the mummy. The concentration profiles additionally provide evidence for a preferential inhalation of THC, while nicotine and cocaine containing drugs seem to have been consumed orally.

In serous ovarian neoplasms the frequency of Ki-ras mutations correlates with their malignant potential.

We analysed 44 tissue samples from serous ovarian neoplasms of different malignant potential for Ki-ras mutations by denaturing gradient gel electrophoresis (DGGE) and direct sequencing after microdissection. Point mutations at codon 12 were found in 7 of 20 tumours of low malignant potential (LMP) (35%) and in 2 of 6 well-differentiated carcinomas (33%). In contrast, no mutations were detected in the 11 poorly differentiated ovarian carcinoma samples or in the 7 serous cystadenomas. The frequency of Ki-ras mutations in serous ovarian tumours seems to correlate with the malignant potential of the neoplasms. The data favour the hypothesis of a de novo development of poorly differentiated ovarian carcinomas and do not support an evolution from LMP tumours or well-differentiated carcinomas.

DNA ploidy and MYC DNA amplification in ovarian carcinomas. Correlation with p53 and bcl-2 expression, proliferative activity and prognosis.

There is increasing evidence that DNA ploidy is a prognostic factor in ovarian carcinomas, but it is uncertain whether MYC DNA amplification is an epiphenomenon of DNA nondiploidy or a distinct biological change with an impact on the clinical course of the disease. To clarify these issues we analysed DNA ploidy by flow and image cytometry and MYC copy number by polymerase chain reaction in archival material from ovarian carcinomas with known follow up. The results were compared with proliferative activity (Ki67 index) and p53 and bcl-2 expression. DNA cytometry revealed nondiploidy in 84 of 144 cases (58.3%). Nondiploidy was statistically significantly correlated with histological tumour type, histological grade, Ki67 index > 10%, FIGO stage, presence of residual tumour after debulking surgery and adverse postoperative outcome. Furthermore, DNA nondiploidy was associated with p53 accumulation. We found that 84.9% of the p53-positive cases were nondiploid. This points to the paramount importance of wild type p53 for the maintenance of genome integrity in this tumour type. MYC DNA amplification was seen in 33.8% (26/77 cases) of ovarian carcinoma. There was no correlation between MYC DNA amplification and histological tumour type, histological grade, FIGO stage, DNA ploidy, proliferative activity or prognosis. However, when p53 and bcl-2 expression was taken into account, a statistically significant correlation between gene alteration or expression patterns and histological tumour type was revealed. The group of mucinous carcinomas demonstrated both MYC DNA amplification and strong bcl-2 expression in 50% and contained the largest fraction of cases without aberration (37.5%). Endometrioid carcinomas were characterized by strong bcl-2 expression in 85%, whereas serous and undifferentiated carcinomas predominantly exhibited p53 alterations, frequently accompanied by bcl-2 overexpression or MYC DNA amplification. Thus, in interaction with other genes MYC DNA amplification may play a role in the determination of the varying differentiation patterns of ovarian carcinomas.

p53-expression and chromosome 17-copy number in colorectal adenomas.

To get better insight into the role of numerical chromosome 17-aberrations and functional loss of the tumor suppressor gene TP53 during the early steps of colorectal carcinogenesis we analyzed paraffin-embedded tumor tissue from 58 colorectal adenomas with different histological features for p53-expression by immunohistology (IH; moAb DO1), #17-copy number by interphase-cytogenetics [nonradioactive in situ-hybridization (NISH) with a centromer-specific DNA-probe (D17Z1)], and DNA-ploidy by flow cytometry (FCM) with special emphasis on histopathological correlation. Seven adenomas (12%) showed nuclear p53-immunoreactivity. p53-expression was correlated with villous/tubulo-villous growth pattern (p=0.005) and grade of atypia (p=0.003) or dysplasia (p=0.0018). #17-aneusomy was present in 31% of the cases (29% deletions, 2% gains). In the FCM-analysis, 33% of the adenomas were DNA-non-diploid. p53-immunoreactivity correlated statistically significantly with FCM-non-diploidy (p=0.004) suggesting a role for the TP53-gene in the aneuploidization process. #17-deletions were associated to p53-immunoreactivity (p=0.046) but no correlation was found between FCM-ploidy and #17-copy number. As for loss of a tumor suppressor gene both alleles have to be affected, our data suggest a multistep process of TP53-inactivation. Whether the subgroup of adenomas with p53-expression might progress faster into invasive carcinoma than p53-negative cases remains to be tested.

Prognostic importance of the expression of CD44 splice variants in oral squamous cell carcinomas.

Considering squamous cell carcinomas (SCCs) of the oral cavity and oropharynx the molecular mechanisms underlying the infiltration and destruction of adjacent tissue as well as the metastatic spread are largely unknown. In this context, the detection of defective expression of cellular adhesion molecules in the tumour cells, e.g. CD44, might be important and correlated with prognosis. Paraffin-embedded tumour-tissue from 99 patients with primary oral and oropharyngeal SCC, additionally including corresponding lymph-node metastases in nine cases, was analysed for expression of the CD44 splice variants v4, v5, v6, v7, and v9 by means of immunohistochemistry. A diminution of at least one of the examined CD44 isoforms compared to the normal oral epithelium was observed in 39.4% of the squamous cell carcinomas. No correlations could be found between CD44 expression and pT- or pN-stage. However, decreased expression of v9 was correlated with higher histological grade (p < 0.001). Moreover, reduced CD44 expression was a statistically significant independent predictor for shorter survival time (p = 0.002) as well as shorter recurrence-free interval (p = 0.004) in addition to pT- and pN-stage. The separate analysis showed that particularly the decreased v7 (p = 0.04) and v9 (p < 0.02) expression in the tumour cells was associated negatively with survival.

Tissue distribution of major matrix metalloproteinases and their transcripts in human breast carcinomas.

The key event of invasive growth of malignant epithelial tumors is the dissolution of the peritumoral basement, membrane (BM). Accordingly, numerous immunohistochemical studies have shown that particularly in breast carcinomas there is an almost complete loss of the BM, even in well-differentiated carcinomas. In order to find out the significance of tumor-associated BM-degradation we localized major matrix metalloproteinases (MMPs) as the most important proteolytic enzymes for connective tissue dissolution. As a prerequisite, we had to identify antibodies reacting specifically on paraffin-embedded tissue material. Extensive pretesting of MMP-2, -3 and -9 antibodies of various sources provided evidence that only a small proportion of the antibodies analyzed showed a specific, positive staining result, as most of the commercial antibodies did not react on the paraffin material or revealed non-specific staining results. Using the specifically reacting antibodies, we analyzed material from 65 cases of invasive ductal breast cancer by immunohistochemistry for the localization of MMP-2, -3 and -9 and by the non-radioactive in-situ hybridization technique for the localization of the MMP-3-mRNA. The specificity of the in-situ hybridization was analyzed using the sense control. We observed a distinct positive immunoreaction for MMP-2, -3 and -9 over both invasive, as well as non-invasive tumor cells, without apparent differences in the staining intensity. Remarkably, there was a significant staining of tumor cell complexes undergoing lymphangiotic dissemination. In addition to this tumor cell staining pattern, a positive immunoreaction, although to reduced proportion, was observed over peritumoral fibroblastic and endothelial stroma cells. Normal breast tissue also revealed a positive immunostaining of epithelial and stromal cells. Using in-situ hybridization, we observed mRNA expression for MMP-3 both in tumor and stroma cells, comparable to the protein data. Normal breast epithelia reacted weakly positive for MMP-3-mRNA. Our data indicate that there is a major active expression of important MMPs in invasive breast carcinomas as the possible cause for the matrix dissolution. These MMPs are synthesized both by tumor and peritumoral stroma cells which may interact with each other. However, the de-novo synthesis and the amount of immunoreactive enzyme protein does not seem to be significantly enhanced in invasive versus noninvasive tumor areas or normal breast epithelia, indicating that other mechanisms, such as enzyme activation and/or differences in the levels of proteinase inhibitors may be biologically essential factors.