Expression of epidermal growth factor receptor in benign and malignant primary tumours of the breast

Preliminary study on oncogene product immunohistochemistry (c-erbB-2, c-myc, ras p21, EGFR) in breast pathology

The expression of oncogene products related to cell growth (c-erbB-2, c-myc, ras p21, EGFR) was investigated in benign (15 cases) and malignant breast lesions (20 cases) by means of immunohistochemistry using the avidin-biotin-peroxidase technique with polyclonal and monoclonal antibodies. The aim of this study was to evaluate the relationship between the staining positivity and various morphological and biological features, such as tumour type, grading, hormone receptor status and cell kinetic parameters.

In benign breast lesions, as expected, the kinetic parameters were low, both for Ki-67 and LI. All the specimens showed a diploid condition (the DI being equal to 1) and we found a limited degree of immunoreactivity for all the growth factors and oncogene products. In breast cancer we studied the distribution of immunohistochemical positivity for EGFR, c-erbB-2, c-myc, ras p21 and Ki-67, which was related to age, nodal status, ER and PgR receptor status, LI, DI and histopathological grading. A significant positive correlation was found both between ras p21 espression and nodal status and ERICA positivity. We observed a strong correlation between LI and Ki-67 and an inverse relation between Ki-67 and ER expression. These findings suggest the importance of studying the relationship between prognostic factors which may provide preoperative prediction in the biological behaviour of breast cancer, not only on biopsy specimens, but also on fine needle aspirates.

Association of microRNA-7 and its binding partner CDR1-AS with the prognosis and prediction of 1st-line tamoxifen therapy in breast cancer

The large number of non-coding RNAs (ncRNAs) and their breadth of functionalities has fuelled many studies on their roles in cancer. We previously linked four microRNAs to breast cancer prognosis. One of these microRNAs, hsa-miR-7, was found to be regulated by another type of ncRNA, the circular non-coding RNA (circRNA) CDR1-AS, which contains multiple hsa-miR-7 binding sites. Based on this finding, we studied the potential clinical value of this circRNA on breast cancer prognosis in a cohort based on a cohort that was previously analysed for hsa-miR-7 and in an adjuvant hormone-naïve cohort for 1^st-line tamoxifen treatment outcomes, in which we also analysed hsa-miR-7. A negative correlation was observed between hsa-miR-7 and CDR1-AS in both cohorts. Despite associations with various clinical metrics (e.g., tumour grade, tumour size, and relapse location), CDR1-AS was neither prognostic nor predictive of relevant outcomes in our cohorts. However, we did observe stromal CDR1-AS expression, suggesting a possible cell-type specific interaction. Next to the known association of hsa-miR-7 expression with poor prognosis in primary breast cancer, we found that high hsa-miR-7 expression was predictive of an adverse response to tamoxifen therapy and poor progression-free and post-relapse overall survival in patients with recurrent disease.

The EGF signaling pathway influences cell migration and the secretion of metalloproteinases by myoepithelial cells in pleomorphic adenoma

During tumor development, benign neoplastic cells are influenced by the expression of cytokines, growth factors, and proteases present in the tumor microenvironment. Epidermal growth factor (EGF) is the most studied growth factor and is considered important for cell proliferation and migration. Metalloproteinases (MMPs) are also involved in tumor progression. The present study aimed to analyze the proliferation, viability and migration index of pleomorphic adenoma myoepithelial cells, in addition to the secretion of MMPs with EGF supplementation. Benign myoepithelial cells were cultured with two different EGF doses (5 and 10 ng/ml), and the influence of EGF on cell proliferation and viability, using trypan blue and MTT assays, respectively, after 24, 48, and 72 h, was evaluated. To analyze cellular morphology, hematoxylin-eosin staining and indirect immunofluorescence using the anti-vimentin antibody, was performed. In vitro migration assays were performed in Transwell chambers with an 8-μm pore covered with Matrigel and supplemented with 5 or 10 ng/ml of EGF, after 96 h. After 4 days of cell culture, ELISA was performed to determine the MMP-2 and MMP-13 levels. One-way analysis of variance (ANOVA) with post hoc Tukey test was applied, with a significance level of 0.05. The results revealed that EGF influences myoepithelial cell morphology, without alteration of proliferation and viability. The migration assay showed that EGF increased the mean index from 16 % in the control group to 40 and 76 % for 5 and 10 ng/ml of EGF, respectively. ELISA revealed that when the cells were supplemented with either of the EGF doses, an increase in MMP-2 levels was observed when compared with the control group (C). This study concludes that EGF aids in the production of MMP-2, which favors the dissolution of the basement membrane, contributing to cell migration and tumor progression, hence permitting contact between the myoepithelial cells and stroma.

Genetically engineered mice as experimental tools to dissect the critical events in breast cancer

Elucidating the mechanism of pathogenesis of breast cancer has greatly benefited from breakthrough advances in both genetically engineered mouse (GEM) models and xenograft transplantation technologies. The vast array of breast cancer mouse models currently available is testimony to the complexity of mammary tumorigenesis and attempts by investigators to accurately portray the heterogeneity and intricacies of this disease. Distinct molecular changes that drive various aspects of tumorigenesis, such as alterations in tumor cell proliferation and apoptosis, invasion and metastasis, angiogenesis, and drug resistance have been evaluated using the currently available GEM breast cancer models. GEM breast cancer models are also being exploited to evaluate and validate the efficacy of novel therapeutics, vaccines, and imaging modalities for potential use in the clinic. This review provides a synopsis of the various GEM models that are expanding our knowledge of the nuances of breast cancer development and progression and can be instrumental in the development of novel prevention and therapeutic approaches for this disease.

Immunohistochemical expression of Epidermal Growth Factor Receptor (EGFR) in canine mammary tissues

Epidermal Growth Factor Receptor (EGFR) has been extensively studied in human breast cancer; however, systematic studies of EGFR protein expression in canine mammary gland tumours are lacking. Therefore, we evaluated its immunohistochemical expression in a series of 136 canine mammary tumours and representative areas of adjacent normal and hyperplastic mammary tissue and investigated a possible correlation between EGFR overexpression and several clinicopathological parameters and survival. In normal and hyperplastic canine mammary glands, EGFR expression was consistently observed in myoepithelial cells, with luminal cells usually negative. In tumour tissues, EGFR overexpression was found in 9 benign (19.6%) and 38 malignant (42.2%) lesions, with EGFR positivity significantly related with malignancy. Besides animal age and tumour size, there were no significant associations between other clinicopathological parameters and EGFR overexpression. On survival analysis, tumours with EGFR overexpression showed a reduced disease-free and overall survival; however these associations failed to reach statistically significant levels.

MMTV-EGF receptor transgene promotes preneoplastic conversion of multiple steroid hormone-responsive tissues

Correlative analyses of tumors and patient-derived cell lines of the human reproductive system suggest that overexpression of EGF contributes to the oncogenic phenotype. However, it is unclear at what stage in disease overexpression of the EGFR is most critical. To assess its role as an initiator of reproductive tissue tumor development, transgenic mice were derived with mouse mammary tumor virus (MMTV)-regulated overexpression of the human EGFR. Although elevated expression of the EGFR in hormonally responsive tissues was observed, only one EGFR transgenic mouse developed a visible tumor over a 2-year period. However, of 12 females monitored over the same time, hyperplasia, hypertrophy, or slight dysplasia was found in mammary glands of 55% of the animals examined, in the uterus or uterine horn of 89%, and in ovaries or oviducts of 100%. None of the reproductive tissues of the male transgenic animals or age-matched, normal mice displayed these changes. These results revealed a role for the EGFR in the initiation of ovarian and uterine cancer and supported previous studies in breast cancer that the receptor can contribute to the neoplastic process in a significant albeit incremental way.

Progressive loss of epidermal growth factor receptor in a subpopulation of breast cancers: implications in target-directed therapeutics

Understanding the molecular etiology and heterogeneity of disease has a direct effect on cancer therapeutics. To identify novel molecular changes associated with breast cancer progression, we conducted phosphoproteomics of the MCF10AT model comprising isogenic, ErbB2- and ErbB3-positive, xenograft-derived cell lines that mimic different stages of breast cancer. Using in vitro animal model and clinical breast samples, our study revealed a marked reduction of epidermal growth factor receptor (EGFR) expression with breast cancer progression. Such diminution of EGFR expression was associated with increased resistance to Gefitinib/Iressa in vitro. Fluorescence in situ hybridization showed that loss of EGFR gene copy number was one of the key mechanisms behind the low/null expression of EGFR in clinical breast tumors. Statistical analysis on the immunohistochemistry data of EGFR expression from 93 matched normal and breast tumor samples showed that (a) diminished EGFR expression could be detected as early as in the preneoplastic lesion (ductal carcinoma in situ) and this culminated in invasive carcinomas; (b) EGFR expression levels could distinguish between normal tissue versus carcinoma in situ and invasive carcinoma with high statistical significance (P < 0.001, n = 81). However, no significant correlation of EGFR expression with disease-free survival and overall survival was observed. This is the first time EGFR expression has been tracked meaningfully and developmentally from the normal condition through disease progression using in vitro, xenograft, and matched normal and tumor samples. Thus, our study provides a new insight into the role of EGFR in breast cancer development. Although no value of EGFR expression in prognosis was found, our findings are likely to have implications in the design of clinical trials targeting the EGFR family of proteins in breast cancer.

The significance of focal myoepithelial cell layer disruptions in human breast tumor invasion: a paradigm shift from the "protease-centered" hypothesis

Human breast epithelium and the stroma are separated by a layer of myoepithelial (ME) cells and basement membrane, whose disruption is a prerequisite for tumor invasion. The dissolution of the basement membrane is traditionally attributed primarily to an over-production of proteolytic enzymes by the tumor or the surrounding stromal cells. The results from matrix metalloproteinase inhibitor clinical trials, however, suggest that this "protease-centered" hypothesis is inadequate to completely reflect the molecular mechanisms of tumor invasion. The causes and signs of ME cell layer disruption are currently under-explored. Our studies revealed that a subset of pre- and micro-invasive tumors contained focal disruptions in the ME cell layers. These disruptions were associated with immunohistochemical and genetic alterations in the overlying tumor cells, including the loss of estrogen receptor expression, a higher frequency of loss of heterozygosity, and a higher expression of cell cycle, angiogenesis, and invasion-related genes. Focal ME layer disruptions were also associated with a higher rate of epithelial proliferation and leukocyte infiltration. We propose the novel hypothesis that a localized death of ME cells and immunoreactions that accompany an external environmental insult or internal genetic alterations are triggering factors for ME layer disruptions, basement membrane degradation, and subsequent tumor progression and invasion.

Peripheral lymph node stromal cells can promote growth and tumorigenicity of breast carcinoma cells through the release of IGF-I and EGF

The regional lymph nodes draining primary breast carcinomas are generally the first site to be invaded by disseminating tumor cells. The extent of lymph node involvement remains the most reliable indicator for staging and prognosis of breast cancer. We have investigated host-tumor interactions between breast carcinoma cells and the lymph node stroma, which may control the outcome of lymph node infiltration. In a previous study, we identified integrin-mediated cell adhesion as a correlate of the metastatic potential of human and rat carcinoma cells. Our present objective was to determine whether lymphatic stromal cells can affect cancer cell growth through the elaboration of growth-modulating factors. Two lymphatic stromal cell lines, ST-A4 and ST-B12, were established from normal rat lymph node stromal cell cultures. SFM conditioned by these cells increased the proliferation of human (Hs578T and MCF-7) and rat (TMT-081) breast carcinoma cells by up to 7-fold and augmented their ability to form colonies in semisolid agar by up to 41-fold. This effect was specific as normal, diploid human breast epithelial cells (Hs578Bst), a nontumorigenic, immortalized human breast epithelial cell line (MCF-10A) and a nonmetastatic rat mammary carcinoma cell line (MT-W9B) had either no or reduced responses. RT-PCR analysis revealed that both lymph node stromal cell lines expressed mRNA transcripts for multiple growth factors, including IGF-I, EGF, HGF and PDGF-alpha, and produced detectable levels of IGF-I, EGF and PDGF-alpha, as assessed by Western blotting. Antibody-mediated depletion assays identified IGF-I and EGF as the major mitogenic factors in the CM. The identification of these cells raises the possibility that the lymph node microenvironment may contribute actively to the process of cancer cell dissemination.

The significance of immunohistochemistry in the diagnosis and therapy of neoplasms

This review article details the diagnostical significance of immunohistochemistry, which has developed during the last quarter of the century. Certainly, the advancement of monoclonal antibody technology has been of great significance in assuring the place of immunohistochemistry in the modern accurate microscopic diagnosis of human neoplasms, as a method of choice in histopathology. The fact still remains that in order to properly assess any immunohistochemical reactivity used for differential diagnostic purposes, the target cells have to be identified as neoplastically transformed cells by routine histopathological techniques. Selected groups of target molecules of great significance in cancer biology are discussed. The discovery of neoplasm-associated antigens has not only made the more accurate diagnosis of human cancer feasible but has also shed light on the extensive immunophenotypical heterogeneity of even the most closely linked human malignancies. The identification of disseminated neoplastically transformed cells by immunohistochemistry has allowed for a clearer picture of cancer invasion and metastasis, as well as the evolution of the tumour cell associated immunophenotype towards increased malignancy. Some possibilities of neoplasm-associated antigen targeted, receptor-directed immunotherapy are discussed and reviewed in this manuscript. Future antineoplastic therapeutical approaches should see the inclusion of a variety of immunotherapies, in the form of an individualised 'cocktail' specific for the particular immunophenotypical pattern associated with each individual patient's neoplastic disease.

Immunocytochemical expression of epidermal growth factor receptor in myoepithelial cells of the breast

The immunohistochemical expression and distribution of epidermal growth factor receptor (EGFr) in mammary myoepithelial cells (MECs) in normal tissue, benign epithelial proliferative lesions, and in situ carcinoma was performed. Results of the current study demonstrated that MECs stained constantly and strongly for EGFr, creating an outer continuous ring surrounding the epithelium of ducts and acini in healthy, in proliferative epithelial lesions, and in in situ carcinoma, both of ductal and lobular type. Foci of microinvasion were easily appreciated for the complete loss of EGFr immunostaining. Epidermal growth factor receptor expression in normal epithelia ranged from negative to weakly positive; it was positive in hyperplasia, whereas it was not constantly negative in in situ carcinoma. In conclusion, immunohistochemical staining for EGFr is diagnostically useful for MEC identification. The specific EGFr in MECs leads the authors to suggest that its expression may be related to the recently recognized high-specialized paracrine function by which the MECs exert the natural mechanical and functional role in the juxtaposition between epithelium and stoma.

The importance of being a myoepithelial cell

The mammary myoepithelial cell was named the 'Cinderella of mammary cell biology' in light of the earlier focus on the luminal cell. Mammary myoepithelial cells have recently been described as 'natural tumour suppressors'. We now need to understand more about their origin and to reconsider their place in the complex process of mammary morphogenesis. In the present review, we discuss the lineage segregation of mammary myoepithelial cells and their functions in mammary gland development. These functions include their effects on luminal cell growth and differentiation, their key role in the establishment of the polarised mammary epithelial bilayer and the control of stromal invasion in breast cancer.

Altered expression of epidermal growth factor receptor in non-involved tissue of cancer-containing breasts

Previous studies have identified functional differences in non-involved breast tissue from cancer-containing breasts. This study has examined the expression of epidermal growth factor (EGFR) protein and mRNA in the non-involved breast of over 100 cancer-containing breasts and compared these with the same number of normal breast tissues from age-matched women with no history of breast cancer. Immunohistochemistry with EGFR1 antibody applied to frozen sections was used for the detection of protein, and in-situ hybridization using a digoxigenin-labelled oligonucleotide probe was the method for detecting mRNA. EGFR protein was detected in myoepithelial cells and to a lesser extent in epithelial cells, where it was predominantly basal or baso-lateral. There was a significant difference in the extent of staining in ducts and lobules between non-involved tissue from cancer-containing breasts and age-matched normal breasts, it being significantly greater in the latter (P<0.001). Labelling for EGFR mRNA was greater and more consistent in myoepithelial cells than epithelial cells overall. Differences were found for intensity of labeling, with it being significantly greater for normal breast tissue (P<0.001) than non-involved tissue from cancer-containing breasts. There is reduced EGFR expression in normal breast tissue from cancer-containing breasts when compared to age-matched breast tissue from women with no history of breast cancer. The mechanisms underlying this are unclear but in previous studies we have identified alterations in myoepithelial cells in cancer-containing breasts and the present findings may represent altered myoepithelial cell function.

Polyunsaturated fatty acids and epidermal growth factor receptor/mitogen-activated protein kinase signaling in mammary cancer

Mammary cancer is the second leading cause of cancer death in women, the second most common neoplasm in dogs and the third leading neoplasm in cats. Mammary tumors are similar in morphology and progression in these species, so cats and dogs are good models for determining treatment or prevention modalities for the human population. Epidemiological, in vitro and rodent studies have demonstrated that polyunsaturated fatty acids (PUFA) can influence the growth, progression and metastasis of mammary cancer. Although a role of PUFA in modulating mammary cancer growth has been shown, the mechanisms by which this occurs remain unclear. Recent studies have demonstrated that PUFA may influence the activity of the epidermal growth factor receptor/mitogen-activated protein kinase pathway, which is involved in regulating several oncogenes (c-myc, c-fos, neu/c-erb-b2) involved in the progression of cancer. We review the potential mechanism by which PUFA may modulate the growth of mammary cancer through regulation of the epidermal growth factor receptor/mitogen-activated protein kinase signal transduction cascade.

The epidermal growth factor receptor in breast cancer

The epidermal growth factor receptor (EGFR)3 is a 170 kD transmembrane tyrosine kinase activated by several ligands. It is required for normal mammary development and lactation and is aberrantly expressed in approximately 40% of breast carcinomas, particularly those with a poor prognostic phenotype. Since EGF receptor levels are elevated in a high proportion of many tumor types its potential as a therapy target is being investigated using the EGF receptor to target toxins, as well as drugs that interfere with signaling and anti-receptor antibodies. These approaches are likely to be most effective when used in the adjuvant situation in combination with chemotherapy.

Relationship between receptors for epidermal growth factor and steroid hormones in normal, dysplastic and neoplastic canine mammary tissues

The concentrations of receptors for epidermal growth factor (EGF-R), oestrogen (ER) and progesterone (PR) were measured in 108 samples from canine mammary tumours and 132 samples of normal mammary tissue removed surgically from 84 bitches. The history and clinical signs were also recorded. Binding sites of high affinity were detected in 70 per cent of both types of tissue and no significant variations in EGF-R concentrations or positivity were observed with the histology, location, size or number of mammary tumours or the age of the animal. A significant direct correlation (P = 0.002) was observed between the concentrations of ER and EGF-R only in malignant tumours. The concentrations of EGF-R were significantly correlated (P = 0.04) in normal mammary tissues adjacent to and distant from the lesions, but not between normal tissue and tumour tissue. No significant differences were observed in the expression of EGF-R in normal and neoplastic tissues from the same bitches. The direct correlation between the concentrations of EGF-R and ER in malignant tumours could be related to an oestrogen-dependent expression of EGF-R or to a similar pattern of regulation of the receptors.

Comparison of radioligand assay and immunostaining for epidermal growth factor receptor in human breast cancer

Epidermal growth factor (EGF) receptor status is a useful prognostic indicator in women with breast cancer. Lack of standardization and correlation of methodology for the detection of EGF receptor has hampered its further evaluation. EGF receptor status was ascertained by immunohistochemistry and radioligand assay in 120 breast cancers. Of 52 tumours negative for EGF receptor on radioligand assay, 47 were negative on immunohistochemistry and, of 68 tumours positive for the receptor on assay, 52 were positive on immunohistochemistry. If the more widely evaluated radioligand assay is assumed to be the 'gold standard', immunohistochemistry has a sensitivity of 81 per cent and a specificity of 91 per cent.

Growth inhibition of xenotransplanted human carcinomas by a monoclonal antibody directed against the epidermal growth factor receptor

In the athymic nude mice model with xenotransplanted human carcinomas, the effect of a monoclonal antibody (MAb 425), directed against the human epidermal growth factor (EGFR), on tumour growth was studied. Five different solid human breast carcinomas and one vulvar epidermoid cancer cell line (A431) were transplanted in nude mice, and treated with MAb 425 2.2 mg intraperitoneally (i.p.) on day 7 post-transplantation. Tumours with EGFR concentrations of > or = 16 fmol/mg soluble cytosolic protein showed growth inhibition, whereas the growth pattern of EGFR-negative tumours was unaffected. Variation of MAb 425 dosage (1.1 versus 2.2 mg) revealed no difference in the growth inhibiting effect. Different application schedules (application on day 0, 12 or 26) showed different onsets and durations of tumour growth inhibition. Repeated application (1.1 mg, day 0 and 12) was followed by a prolonged inhibitory effect. Our results suggest that growth inhibition of EGFR-positive tumours by MAb 425 may lead to an additional treatment option for patients with EGFR-positive cancer.

Expression of epidermal growth factor receptor (EGFR) in non-affected and tumorous mammary tissue of female dogs

Epidermal growth factor (EGFR), oestrogen (ER), and progestin (PR) receptor concentrations were determined by radioligand binding assay in non-affected mammary tissues (n = 13) and benign (n = 11) and primary/locally recurrent malignant proliferative mammary lesions (n = 45) and metastases (n = 19) in 65 female dogs. The number of specimens expressing EGFR was not significantly different among these tissues, but EGFR concentration was lower in metastases (P = 0.02) than in benign or primary/locally recurrent malignant lesions not mixed with non-affected mammary tissue. The presence of non-affected mammary tissue in primary cancer specimens was noticed as a factor that may influence results of receptor measurements. No relation was found between the expression of EGFR and that of ER or PR in non-affected or in tumorous mammary tissues. It was concluded that in the dog mammary gland EGFR expression is not associated with conditions of steroid receptor absence of biological agressiveness of neoplastic growth.

Prevalence of aneuploidy, overexpressed ER, and overexpressed EGFR in random breast aspirates of women at high and low risk for breast cancer

Breast tissue biomarkers which accurately predict breast cancer development within a 10 year period in high risk women are needed but currently not available. We initiated this study to determine 1) the prevalence of one or more breast tissue abnormalities in a group of women at high risk for breast cancer, and 2) if the prevalence of biomarker abnormalities is greater in high risk than in low risk women. Eligible high risk women were those with a first degree relative with breast cancer, prior breast cancer, or precancerous mastopathy. Low risk women were those without these or other major identifiable risk factors. Ductal cells were obtained via random fine needle aspirations and cytologically classified. Biomarkers included DNA ploidy, estrogen receptor (ER), and epidermal growth factor receptor (EGFR). The prevalence of DNA aneuploidy was 30%, overexpression of ER 10%, and overexpression of EGFR 35%, in the 206 high risk women whose median 10 year Gail risk (projected probability) of developing breast cancer was 4.5%. The prevalence of aneuploidy and overexpressed EGFR was significantly higher in the high risk women than in the 25 low risk controls (p < 0.002), whose median 10 year Gail risk was 0.7%. The difference in the prevalence of ER overexpression between high and low risk groups was not statistically significant (p = 0.095). This may be due to the low prevalence of overexpressed ER and the small number of controls. A significant difference was noted in the prevalence of one or more abnormal biomarkers between the high risk and low risk women (p < 0.001). A large prospective trial is needed to determine if one or more of these biomarkers, is predictive of breast cancer development.

EGF receptor expression, regulation, and function in breast cancer

Epidermal growth factor receptor (EGFR) overexpression correlates with both loss of estrogen receptor (ER) and poor prognosis in breast cancer. Interestingly, in normal breast EGFR appears to be expressed more frequently than in malignant tissue, and there may be a different relationship between ER and EGFR. A variety of cellular regulators, such as EGF, TGF alpha, phorbol esters, and steroid hormones, are capable of altering the level of EGFR expression in breast cells. However, much work remains to be done on the mechanistic details of EGFR regulation in this disease. The significance of EGFR as an oncogene in breast cancer is compounded by its potential interactions with other oncogenes such as c-erbB-2 and c-myc. Additionally, several recent studies have placed EGFR prominently in the signal transduction pathway, demonstrating that the EGFR-ligand system may play important roles throughout the course of malignant progression in breast cancer.

Expression of epidermal growth factor receptor in chick embryo myocardiocytes: relation with desmin expression during cardiac development

The epidermal growth factor receptor is related with processes of cell replication and differentiation. We used the intermediate filament protein desmin as a marker to study the relation between muscle cell differentiation and modifications in the expression of this receptor during heart development in the chick embryo. Epidermal growth factor receptor was expressed as early as Hamburger and Hamilton's stage 17, when myocardiocytes are still poorly differentiated and desmin-negative. Expression became steadily weaker as the heart matured, and decreased after Hamburger and Hamilton's stage 25, a key stage in heart maturation characterized by a sharp increase in desmin expression. Our findings suggest that in the chick embryo, the expression of epidermal growth factor receptor becomes steadily weaker as myocardiocyte differentiation progresses.

Epidermal growth factor receptor in breast cancer. Comparison with non malignant breast tissue

Epidermal growth factor receptors were measured using a radioligand binding assay in membrane preparations from 67 cancer and 25 non-malignant tissues. The binding characteristics of EGFr were similar in tumour and normal breast membranes. The concentrations were significantly higher in non-malignant tissue than in cancer. EGFr concentrations were directly correlated with steroid receptors in non-malignant tissue, whereas in cancer an inverse correlation between EGFr and steroid receptors was found.

Antigenic profile of mammary fibroadenoma and cystosarcoma phyllodes. A study using antibodies to estrogen- and progesterone receptors and to a panel of cell surface molecules

Using serial frozen sections, monoclonal antibodies and an indirect immunoperoxidase method, 13 fibroadenomas (FA) and 3 cystosarcomas phyllodes (CSP) were analyzed for the expression of Egp34, HEA319-antigen, leucocyte differentiation antigens CD10, CD30, CD57, CD72, CDw75, and CD77, epidermal growth factor receptor (EGFR), estrogen (ER) and progesterone receptor (PR), and transferrin receptor (CD71). Egp34, CDw75, HEA319 antigen, CD10, and CD30 turned out to be consistently expressed in different cell types constituting FA and CSP and revealed that in malignant CSP the myoepithelial compartment acquires the ability to invade the stroma. Phenomenologically, the variable mode of expression of CD57 in myoepithelial cells, of CD77 in ductal epithelium, and of CD72 in both epithelial and stromal cells is suggestive for reflecting differences in their functional state but cannot be further interpreted at present. Expression of PR and ER was restricted to duct cells and was relatively independent, non-systematical. However, expression of ER and EGFR was inverse. This was also true for EGFR and CD71 in both duct cells and myoepithelial cells of FA. In contrast, stromal cells of FA were able to co-express EGFR and CD71 in the absence of PR and ER. This suggests a hormone-independent stimulation of the stromal cell compartment, possibly leading to local proliferation as the primary event in tumorigenesis of FA. In malignant CSP, however, the main proliferating cell is an abnormally mobile, HEA319 antigen-, CD10- and CD30-positive myoepithelial cell found to co-express ERFR and CD71 which is abnormal for this cell type but encountered in (myo-)fibroblasts of FA.

Expression of epidermal growth factor receptor in normal colorectal mucosa, adenoma, and carcinoma

Using the monoclonal antibody EGF-R1, the expression of epidermal growth factor receptor (EGFR) was investigated immunohistochemically in normal colonic mucosa distant from and adjacent to colonic neoplasms, in 25 adenomas and in 144 unselected colorectal carcinomas. EGFR expression was an inconsistent phenomenon in each of these conditions. It was not expressed in 23/44 non-neoplastic mucosa specimens distant from and in 26/44 mucosae adjacent to colon tumours; 15/25 adenomas and 71 (49.3%) of the carcinomas failed to contain detectable amounts of EGFR. In contrast, large amounts of EGFR were found in 4 non-neoplastic mucosae at both locations, in 3 adenomas and in 11 (7.6%) carcinomas. The remaining cases showed complex patterns of EGFR-expression. In comparing mucosae close to and distant from a colonic tumour, only minor differences in EGFR content were observed. The intra-individual comparison of the mode of EGFR expression in non-neoplastic and neoplastic epithelium revealed an overexpression of EGFR in carcinomas in about one third of the 44 cases examined. One third showed no obvious differences, and one third showed lower levels of EGFR expression within the tumour. We conclude that the mode of EGFR expression in normal and neoplastic colon epithelium is variable and reflective of inter-individual constitutive differences rather than of abnormalities in gene regulation. Statistical analysis failed to reveal correlations between the mode of EGFR expression and tumour grade, type or Dukes stage.

Immunohistochemical expression of epidermal growth factor receptors in human adrenocortical carcinoma

Epidermal growth factor (EGF) receptors were examined immunohistochemically in 64 adrenocortical carcinomas obtained at autopsy, and in 23 adrenocortical adenomas and seven pheochromocytomas obtained during surgery. In the nonneoplastic adrenal gland, EGF receptors were scattered to the zona glomerulosa, zona fasciculata, and zona reticularis. Adrenocortical carcinomas (63 of 64), more than adrenocortical adenomas (10 of 23) or pheochromocytomas (four of seven), stained positively for EGF receptors (P less than .01). The immunoreactivity was limited to the cytoplasm, cell membrane, and chromatin. When the antibody was immunoabsorbed with an excess of immunogen peptide, there was no evidence of immunostaining. The adrenocortical carcinomas could be classified into 16 cases of the well-differentiated type, 33 cases of the moderately differentiated type, and 15 cases of the poorly differentiated type. There was no relationship between histologic grading and staining intensity of the EGF receptors. On the other hand, more than 80% of the cases of adrenocortical carcinomas revealed a moderate to high intensity for EGF receptors. In 62 of the 64 patients, there was already metastases to other organs. We conclude that the expression of EGF receptors is associated with tumor growth and/or metastatic potential in adrenocortical carcinoma.

Immunohistochemical expression of epidermal growth factor receptor in salivary gland tumours

Immunohistochemical localization of epidermal growth factor receptor (EGFR) in normal salivary glands and tumours (108 cases) was studied using a monoclonal antibody. In the normal salivary glands, EGFR was occasionally detected in ductal segments of intercalated, striated, and excretory ducts, but not in acinar cells. The frequency of positive EGFR staining in salivary gland tumours was not high: pleomorphic adenoma, 33.8%; mucoepidermoid tumour, 25.0%; adenolymphoma, 44.4%; and sialoadenocarcinoma, 66.6%. Pleomorphic adenomas showed positive staining for EGFR on the luminal side of luminal cells and in squamous metaplastic cells of tumour tissue. Some modified myoepithelial cells were also reactive whereas outer spindle tumour cells were unstained. Adenolymphomas regularly exhibited positive EGFR staining in the cell membrane; mucoepidermoid carcinoma displayed positive staining in cell membranes in epidermoid tumour cells and cytoplasmic staining in mucous-secreting tumour cells. Sialocarcinomas revealed cell membrane staining and whole cytoplasmic staining for EGFR. The immunohistochemical localization of EGFR could be classified into two types, one the cell membrane-positive type found in epithelial tumour cells, and the second the cytoplasmic positive type seen in normal ductal cells, the luminal tumour cells of pleomorphic adenomas and mucous-secreting tumour cells.

Nucleolar grading of breast cancer. Comparative studies on frequency and localization of nucleoli and histology, stage, hormonal receptor status and lectin histochemistry

The localization and number of nucleoli of tumour nuclei were examined after conventional histological typing of breast carcinomas (WHO classification), staging, biochemical receptor status, and lectin binding site histochemistry. With increasing histological atypia and grade of malignancy, the frequency of nucleoli increased significantly and their location shifted from the center to the nuclear periphery. These changes correlated with an increase in indices of mitosis and cell loss. The nucleolar size correlated with the increase in the grade of malignancy. Hormone receptor and lectin binding site positive carcinomas were characterized by a low nucleolar frequency and by small nucleoli in central position, whereas carcinomas with high grades of malignancy and negative hormone receptor and lectin binding site status showed large, often multiple nucleoli in eccentrical position at a high frequency. The studies have demonstrated that nucleolar status is an easily practicable histological/cytological method for use in the assessment of prognosis of carcinomas of the breast.