Biomedical subjects

W J Gullick

Publications and source records attributed to W J Gullick.

At least 37 records · Page 2Linked to original sources

PubMed2000

c-erbB-4 protein expression in human breast cancer.

The Type 1 family of growth factor receptors includes epidermal growth factor receptor (EGFR), c-erbB-2, c-erbB-3 and c-erbB-4. Overexpression of the first two members is associated with poorer prognosis in patients with breast carcinoma. In this study we examined the expression of c-erbB-4 protein using the monoclonal antibody HFR-1. A total of 127 consecutive cases of primary operable invasive breast carcinoma presenting between 1975 and 1977 were studied. All patients were managed by simple mastectomy or conservation surgery with radiotherapy and no adjuvant therapy given. Long-term follow-up was maintained. Routine, formalin-fixed, paraffin-embedded tumour samples were used and sections were stained immunohistochemically using the Duet StreptABC method. Immunoreactivity was classified using a simple semi-quantitative scoring method. Protein expression was generally low but definite positive cytoplasmic, membranous and nuclear reactivity was identified in 58%, 41% and 25% of cases respectively. Expression at all three sites demonstrated significant inverse associations were histological grade. In addition, membrane accentuation correlated inversely with the Nottingham Prognostic Index (NPI), while cytoplasmic reactivity showed a positive association with c-erbB-3 expression. No significant associations were found with disease-free interval or survival. The results of this study demonstrate that higher levels of c-erbB-4 protein expression are associated with a more differentiated histological phenotype in contrast to the other members of the Type 1 family. Larger series with extended follow-up will be required to ascertain definitively the prognostic value of c-erbB-4 expression in breast carcinoma.

Adult↗

PubMed2000

The EGF-CFC family: novel epidermal growth factor-related proteins in development and cancer.

The EGF-CFC gene family encodes a group of structurally related proteins that serve as important competence factors during early embryogenesis in Xenopus, zebrafish, mice and humans. This multigene family consists of Xenopus FRL-1, zebrafish one-eyed-pinhead (oep), mouse cripto (Cr-1) and cryptic, and human cripto (CR-1) and criptin. FRL-1, oep and mouse cripto are essential for the formation of mesoderm and endoderm and for correct establishment of the anterior/posterior axis. In addition, oep and cryptic are important for the establishment of left-right (L/R) asymmetry. In zebrafish, there is strong genetic evidence that oep functions as an obligatory co-factor for the correct signaling of a transforming growth factor-beta (TGFbeta)-related gene, nodal, during gastrulation and during L/R asymmetry development. Expression of Cr-1 and cryptic is extinguished in the embryo after day 8 of gestation except for the developing heart where Cr-1 expression is necessary for myocardial development. In the mouse, cryptic is not expressed in adult tissues whereas Cr-1 is expressed at a low level in several different tissues including the mammary gland. In the mammary gland, expression of Cr-1 in the ductal epithelial cells increases during pregnancy and lactation and immunoreactive and biologically active Cr-1 protein can be detected in human milk. Overexpression of Cr-1 in mouse mammary epithelial cells can facilitate their in vitro transformation and in vivo these Cr-1-transduced cells produce ductal hyperplasias in the mammary gland. Recombinant mouse or human cripto can enhance cell motility and branching morphogenesis in mammary epithelial cells and in some human tumor cells. These effects are accompanied by an epithelial-mesenchymal transition which is associated with a decrease in beta-catenin function and an increase in vimentin expression. Expression of cripto is increased several-fold in human colon, gastric, pancreatic and lung carcinomas and in a variety of different types of mouse and human breast carcinomas. More importantly, this increase can first be detected in premalignant lesions in some of these tissues. Although a specific receptor for the EGF-CFC proteins has not yet been identified, oep depends upon an activin-type RIIB and RIB receptor system that functions through Smad-2. Mouse and human cripto have been shown to activate a ras/raf/MAP kinase signaling pathway in mammary epithelial cells. Activation of phosphatidylinositol 3-kinase and Akt are also important for the ability of CR-1 to stimulate cell migration and to block lactogenic hormone-induced expression of beta-casein and whey acidic protein. In mammary epithelial cells, part of these responses may depend on the ability of CR-1 to transactivate erb B-4 and/or fibroblast growth factor receptor 1 through an src-like tyrosine kinase.

Amino Acid Sequence↗

PubMed1999

Intracellular movement of green fluorescent protein-tagged phosphatidylinositol 3-kinase in response to growth factor receptor signaling.

Phosphatidylinositol 3-kinase (PI 3-kinase) is a lipid kinase which has been implicated in mitogenesis, protein trafficking, inhibition of apoptosis, and integrin and actin functions. Here we show using a green fluorescent protein-tagged p85 subunit that phosphatidylinositol 3-kinase is distributed throughout the cytoplasm and is localized to focal adhesion complexes in resting NIH-3T3, A431, and MCF-7 cells. Ligand stimulation of an epidermal growth factor receptor/c-erbB-3 chimera expressed in these cells results in a redistribution of p85 to the cell membrane which is independent of the catalytic activity of the enzyme and the integrity of the actin cytoskeleton. The movement is, however, dependent on the phosphorylation status of the erbB-3 chimera. Using rhodamine-labeled epidermal growth factor we show that the phosphatidylinositol 3-kinase and the receptors colocalize in discrete patches on the cell surface. Low concentrations of ligand cause patching only at the periphery of the cells, whereas at high concentrations patches were seen over the whole cell surface. Using green fluorescent protein-tagged fragments of p85 we show that binding to the receptor requires the NH(2)-terminal part of the protein as well as its SH2 domains.

Animals↗

PubMed1999

Cell specific transformation by c-fms activating loop mutations is attributable to constitutive receptor degradation.

Expression of a receptor for human macrophage-colony stimulating factor (M-CSF or CSF-1), containing a point mutation which changes an aspartate to a valine at position 802 of the activating loop of the kinase domain, potently transforms the haemopoietic cell line FDC-P1 yet prevents Rat-2 fibroblast transformation. In order to understand this apparent paradox, aspartate 802 was changed by cassette mutagenesis to each of the other 19 amino acids. All hydrophobic amino acid substitutions were transforming when tested in FDC-P1 cells yet inactivating when tested in Rat-2 fibroblasts. These same amino acid substitutions also activated receptor degradation, strongly suggesting a causal relationship between receptor degradation and inactivation in fibroblasts. Point mutations or small deletions of Y708 within the kinase insert region of the mutant D802V receptor partly inhibited receptor degradation. The more stable D802V receptor derivatives were able to transform both FDC-P1 cells and Rat-2 fibroblasts, so establishing that the cell specific effect of the c-fmsD802V activating loop mutation is attributable to receptor degradation which accompanies kinase activation and prevents the transformation of Rat-2 but not of FDC-P1 cells.

Animals↗

PubMed1999

Processing and juxtacrine activity of membrane-anchored betacellulin.

Betacellulin (BTC) was originally isolated as a secreted growth factor from a mouse pancreatic beta-tumor cell line, whereas the cDNA sequence predicts that BTC is synthesized as a larger transmembrane protein. In the present study, we have characterized the membrane-anchored forms of BTC, using Chinese hamster ovary (CHO) cells, mouse fibroblast A9 cells, and a human breast cancer cell line MCF-7, all of which were stably transfected with human BTC cDNA. A9 and MCF-7 transfectants produced membrane-anchored BTC isoforms of 21, 25, 29, and 40 kDa on the cell surface, as well as a secreted BTC isoform. CHO transfectants secreted little BTC but accumulated the membrane-anchored isoforms. The cleavage of the membrane-anchored forms to release a secreted from of BTC was not enhanced by biological mediators such as a phorbol ester, which stimulates the cleavage of other membrane-anchored growth factors. The membrane-anchored forms of BTC expressed on the transfected cells induced the insulin production and/or promoted the growth in subclones of AR42J rat pancreatic cells. These results suggest that the membrane-anchored BTC can function as a juxtacrine factor in regulating the growth and differentiation of pancreatic endocrine cells.

3T3 Cells↗

PubMed1999

Expression of cripto and amphiregulin in colon mucosa from high risk colon cancer families.

We assessed the expression of the epidermal growth factor (EGF)-related peptides, cripto-I (CR-I) and amphiregulin (AR), in a small panel of human colon adenomas and carcinomas. CR-I immunoreactivity was found in 17/31 (55%) of colon adenomas, and in 33/39 (84%) colon carcinomas. AR immunostaining was observed in 16/26 adenomas (61%) and in 20/26 carcinomas (77%). CR-I and AR staining were also assessed in 29 specimens from 24 individuals that belong to families with high incidence of colorectal carcinoma, and in 5 non-high risk individuals. Expression of CR-I was detected in 18/29 (62%) of high risk colon mucosa specimens, but only in 1/5 (20%) specimens from non-high risk individuals, while AR staining was found in 20/29 (69%) and in 4/5 (80%) of colon mucosa samples from high and low risk individuals, respectively. A majority (21/29; 72%) of the specimens from the high risk individuals had a high proliferative rate, as measured by Ki-67 staining. A statistically significant correlation was found between high proliferative rate, increased expression of CR-I and reduced expression of AR in the mucosa specimens from high risk individuals, suggesting that these might represent early events in colon tumorigenesis.

Adenoma↗

PubMed1999

Expression of the c-erbB-3/HER-3 and c-erbB-4/HER-4 growth factor receptors and their ligands, neuregulin-1 alpha, neuregulin-1 beta, and betacellulin, in normal endometrium and endometrial cancer.

The objective of this study was to determine the immunohistochemical expression of the c-erbB-3 and c-erbB-4 growth factor receptors and their principal ligands, the neuregulins and betacellulin, in normal endometrium and determine whether there was evidence of under- or overexpression in endometrial adenocarcinoma. Immunohistochemistry was performed using well-characterized antibodies against each of the five proteins analyzed on formalin-fixed, paraffin-embedded archival material. Forty-three normal endometrial samples (16 proliferative, 19 secretory, and 8 hyperplastic) and 41 endometrial adenocarcinoma cases were analyzed. There was variable expression of the growth factor receptors and the ligands in the two principal phases of the menstrual cycle as well as in endometrial adenocarcinoma. In normal endometrium, the c-erbB-3 receptor was weakly expressed in both phases. The c-erbB-4 receptor and all of the ligands examined, neuregulin alpha, neuregulin beta, and betacellulin, were expressed at significantly higher levels in the secretory as compared with the proliferative phase of the menstrual cycle, suggesting a role for these proteins in endometrial maturation. In endometrial adenocarcinoma, overexpression of c-erbB-3, c-erbB-4, and betacellulin with underexpression of neuregulin a as compared with normal controls was observed. Neuregulin beta expression was not found to be significantly different in the two groups. These results suggest that signaling through the c-erbB-3 and c-erbB-4 receptors and the ligands neuregulin alpha, neuregulin beta, and betacellulin are important in endometrial carcinogenesis.

Amino Acid Sequence↗

PubMed1998

c-erbB3 and c-erbB4 expression is a feature of the endocrine responsive phenotype in clinical breast cancer.

We examined c-erbB3 and c-erbB4 mRNA expression in 47 primary breast cancer samples by simultaneous RT-PCR and have investigated correlations between these parameters and the expression of both ER and EGFR mRNA and protein as measured by RT-PCR and ICA and with Ki67 immunostaining. A direct association was found between c-erbB3 and c-erbB4 mRNA and ER marker status measured by either RT-PCR (c-erbB3 P = 0.0003; c-erbB4 P = 0.02) or ICA (c-erbB-3 P = 0.002; c-erbB4 P = 0.01). Inverse associations were seen between c-erbB3 and c-erbB4 mRNA marker status and EGFR membrane protein (c-erbB3: P = 0.003; cerbB4: P = 0.003) and mRNA (c-erbB4: P = 0.009) status. These associations were reinforced by Spearman Rank Correlation Tests. A significant relationship was seen between Ki67 and c-erbB4 mRNA status and level. Measurements of c-erbB3 protein levels in tumour samples removed from a further 89 patients of known response to endocrine therapy: (i) confirmed the relationship between c-erbB3 and ER and (ii) identified that patients whose ER positive tumours expressed high levels of c-erbB3 were most likely to benefit from endocrine measures. A non-significant trend was recorded between c-erbB3 levels and Ki67 immunostaining. These results clearly demonstrate that increased c-erbB3 and c-erbB4 expression appears to be associated with the prognostically-favourable ER phenotype.

Antineoplastic Agents, Hormonal↗

PubMed1998

Expression of an oncogenic mutant EGF receptor markedly increases the sensitivity of cells to an EGF-receptor-specific antibody-toxin.

EGFRvIII is a ligand-independent, constitutively active variant of the epidermal growth factor receptor (EGFR) that is specifically expressed in gliomas and various other human malignancies and has been proposed as a target for directed tumor therapy. We have recently constructed a highly potent single-chain antibody-toxin, scFv(14E1)-ETA, which consists of the variable domains of the antibody 14E1 specific for human full-length EGFR genetically fused to a truncated form of Pseudomonas exotoxin A. We demonstrate here binding of 14E1 antibody to both full-length and variant EGFR. In contrast to a recombinant toxin containing transforming growth factor-alpha (TGF-alpha) as a cell targeting domain, scFv(14E1)-ETA was highly active on cells expressing EGFRvIII. Surprisingly, scFv(14E1)-ETA displayed cell killing activity on EGFRvIII-expressing cells that was up to 100-fold higher than on control cells expressing full-length EGFR. No differences in the binding affinities of scFv(14E1)-ETA to full-length EGFR or EGFRvIII were observed, suggesting that events downstream of immunotoxin binding are responsible for the increased sensitivity of EGFRvIII-expressing cells. This might have implications for the development of therapeutic reagents simultaneously targeting different forms of the EGFR.

3T3 Cells↗

PubMed1998

The immunohistochemical detection of cripto-1 in benign and malignant human bladder.

The recently identified epidermal growth factor-related peptide cripto-1 has been previously implicated in the development of the malignant phenotype. The identification of gene products that can act as prognostic markers in bladder cancer would be value in determining the management of this heterogeneous group of patients. This study examines cripto-1 expression in benign and malignant bladder using immunohistochemical techniques. The expression of cripto-1 protein in benign and malignant bladder was examined in 45 bladder tumours (Ta/T1 n = 26, T2 n = 5, T3/T4 n = 14) and six benign controls. All 45 tumours showed positive cytoplasmic staining for cripto-1, including areas of carcinoma in situ. None of the six benign controls showed any evidence of positive cripto-1 staining. Twenty-three (60 per cent) bladder tumours had areas of papillary tumour that showed strong positive staining for cripto-1 as opposed to six (29 per cent) sections of histologically normal urothelium adjacent to tumour (P < 0.05). There was no association between cripto-1 staining and tumour grade, stage, or clinical outcome. Cripto-1 protein appears to be specifically expressed in malignant and benign adjacent urothelium of patients with bladder cancer. Its clinical significance, however, remains to be determined.

Aged↗

PubMed1998

Expression of the c-erbB-4/HER4 protein and mRNA in normal human fetal and adult tissues and in a survey of nine solid tumour types.

The c-erbB-4/HER4 receptor belongs to the family of the type I growth factor receptors. Mouse monoclonal antibodies have been raised to the cytoplasmic domain of the c-erbB-4 receptor and characterized; the antibody HFR-1 has been used to determine the pattern of expression of the c-erbB-4 protein immunohistochemically in formalin-fixed, paraffin-embedded adult and fetal tissues. The expression of c-erbB-4 mRNA was determined by using 35S-labelled riboprobes and tissue in situ hybridization. c-erbB-4 is widely expressed in many adult and fetal tissues, including the lining epithelia of the gastrointestinal, urinary, reproductive, and respiratory tracts, as well as the skin, skeletal muscle, circulatory, endocrine, and nervous systems. The developing brain and heart notably express high levels of this receptor. The pattern of c-erbB-4 protein expression is also reported in a survey of common solid human cancers. Loss of expression was noted in 40-80 per cent of adenocarcinomas and up to 100 per cent of squamous cell carcinomas, whereas overexpression was observed in about 10-20 per cent of adenocarcinomas and astrocytomas. In general, the pattern of c-erbB-4 expression in normal tissues and cancers suggests that it tends to be associated with the differentiated compartment.

Adenocarcinoma↗

PubMed1998

The type 1 growth factor receptor family: new ligands and receptors and their role in breast cancer.

The type 1 family of growth factor receptors, which consist of the epidermal growth factor receptor, c-erbB-2, c-erbB-3, and c-erbB-4, are expressed in normal breast ductal epithelial cells and in some breast cancers. Nine genes have now been identified which code for ligands. In some cases the genes are spliced into a series of proteins which differ in structure, but all retain an EGF-like element responsible for receptor recognition. The EGF receptor is expressed in normal breast and in some cancers, but is apparently reduced in expression in other cases. Cancers with EGF receptors appear to represent a greater threat to patients as in most studies they are associated with a shorter time to relapse and overall survival. The c-erbB-2 protein is overexpressed at very high levels in about one fifth of breast cancers and is indicative of poor prognosis. Other cancers may express lesser degrees of overexpression but it is not clear if this is biologically or clinically significant. The c-erbB-3 protein is expressed in normal breast epithelial cells and has been reported to be present at high levels in some cancers but at normal levels or at lower than normal levels in some others. The limited studies to date suggest that when measured on its own c-erbB-3 expression is not predictive. c-erbB-4 is also expressed in normal breast and in some cancers but no studies have yet been performed to address whether it is associated with disease behaviour. In the future it is likely that a greater understanding of the function of this complex family of interacting proteins will assist in gaining the maximum predictive power from measurement of their expression in human breast cancer.

Amino Acid Sequence↗

PubMed1998

Purification and characterization of a recombinant human cripto-1 protein.

Cripto-1 (CR-1) is a novel protein that contains a modified EGF-like motif and that does not directly bind to any of the known erb B type-1 receptor tyrosine kinase receptors. To more clearly define the biological effects of CR-1 and to more adequately compare the structure-function relationships of CR-1 with other members of the EGF family of growth factors, we have expressed a modified, full-length recombinant human CR-1 protein (rhCR-1) in E. coli and have devised a procedure for the solubilization, refolding and purification of a biologically active form of this protein. We have generated the mature form of hCR-1 from computer assisted predictions of potential signal peptide cleavage sites. Expression of the modified rhCR-1 protein in E. coli was limited to the inclusion bodies. The rhCR-1 protein was found to be expressed at high levels in bacterial cells when fused to a histidine-tag sequence. Refolding of rhCR-1 was found to be difficult because of the large number of cysteine residues in the protein which results in protein aggregation. By chemically modifying the cysteine residues in the rhCR-1 protein with 3-trimethylammoniopropyl methanethiosulfonate, additional positive charges have been introduced into the protein by this disulfiding reagent. This modification facilitates solubilization of the protein when rhCR-1 is denatured. The solubilized, denatured protein was then purified by CM cation exchange and C4 reverse phase HPLC chromatography and refolded in a redox buffer. The refolded, modified rhCR-1 protein was found to be biologically active by its ability to inhibit beta-casein expression, to stimulate the tyrosine phosphorylation of Shc and the activation of MAPK and by its capacity to facilitate branching growth of mouse mammary epithelial cells in type I collagen gels.

Animals↗

PubMed1998

Type I growth factor receptors: current status and future work.

The type 1 family of growth factor receptors consists of the epidermal growth factor receptor (EGFR), and ErbB-2, ErbB-3 and ErbB-4. Six ligands are known to bind directly to EGFR, none (at present) to ErbB-2, and a family of ligands collectively called the neuregulins bind to both ErbB-3 and ErbB-4. It is now apparent that the receptors function in various heterodimeric pairs, depending on their concentrations, the concentrations of particular ligands in the environment and some intrinsic degree of dimer selectivity. Overexpression of EGFR, ErbB-2 and ErbB-3 has been found commonly in solid human tumours. ErbB-4 has not yet been examined. The EGFR is also activated by various mutations in brain tumours and possibly in other tumour types. These changes appear to be one of the causes of malignant transformation. They may also provide information regarding the course of disease and response to current treatments. Finally, they are targets for a variety of new forms of treatment being developed in the laboratory, in preclinical models and in a few cases in clinical trials.

Dimerization↗

PubMed1997

Chemical synthesis, structural modeling, and biological activity of the epidermal growth factor-like domain of human cripto.

Cripto, also known as human teratocarcinoma-derived growth factor 1 (TDGF-1), contains a 40 amino acid region with some similarity to the epidermal growth factor (EGF) domain. However, sequence homology is largely restricted to the classical cysteine/glycine motif with only limited similarities in other regions. Significant differences to human EGF include the absence of all seven residues between the two N-terminal half-cystines and a five-residue shorter loop between the third and fourth half-cystines. We examine the hypothesis that, in spite of these differences, cripto can adopt the characteristic EGF-like 1-3, 2-4, 5-6 disulfide bond pattern. A comparative structural model of the growth factor cripto was constructed on the basis of its similarity to EGF, transforming growth factor alpha (TGF-alpha), and the EGF-like domain of human clotting factor IX. The predicted disulfide bridges and disulfide-bridged loops were analyzed and appear viable in the modeled structure. Moreover, to ascertain the importance of disulfide arrangement for cripto bioactivity, two 47-residue peptides were synthesized and then refolded using either a simple oxidative or a controlled sequential refolding protocol. The cripto peptides were tested for their ability to stimulate MAP-kinase activity, for inhibition of beta-casein induction, and for Shc phosphorylation in MDA-MB 453 human mammary carcinoma cells and HC-11 mouse mammary epithelial cells. Data suggest that cripto does adopt the 1-3, 2-4, 5-6 disulfide pattern and thus forms the classical EGF-like fold in spite of the significant deletions within the folding domain. The predicted structure of cripto shows some of the characteristics of both the ErbB1- and ErbB3/ErbB4-binding growth factors.

Amino Acid Sequence↗

PubMed1997

Cripto enhances the tyrosine phosphorylation of Shc and activates mitogen-activated protein kinase (MAPK) in mammary epithelial cells.

Cripto-1 (CR-1), a recently discovered protein of the epidermal growth factor (EGF) family, was found to interact with a high affinity, saturable binding site(s) on HC-11 mouse mammary epithelial cells and on several different human breast cancer cell lines. This receptor exhibits specificity for CR-1, since other EGF-related peptides including EGF, transforming growth factor alpha, heparin-binding EGF-like growth factor, amphiregulin, epiregulin, betacellulin, or heregulin beta1 that bind to either the EGF receptor or to other type 1 receptor tyrosine kinases such as erb B-3 or erb B-4 fail to compete for binding. Conversely, CR-1 was found not to directly bind to or to activate the tyrosine kinases associated with the EGFR, erb B-2, erb B-3, or erb B-4 either alone or in various pairwise combinations which have been ectopically expressed in Ba/F3 mouse pro-B lymphocyte cells. However, exogenous CR-1 could induce an increase in the tyrosine phosphorylation of 185- and 120-kDa proteins and a rapid (within 3-5 min) increase in the tyrosine phosphorylation of the SH2-containing adaptor proteins p66, p52, and p46 Shc in mouse mammary HC-11 epithelial cells and in human MDA-MB-453 and SKBr-3 breast cancer cells. CR-1 was also found to promote an increase in the association of the adaptor Grb2-guanine nucleotide exchange factor-mouse son of sevenless (mSOS) signaling complex with tyrosine-phosphorylated Shc in HC-11 cells. Finally, CR-1 was able to increase p42(erk-2) mitogen-activated protein kinase (MAPK) activity in HC-11 cells within 5-10 min of treatment. These data demonstrate that CR-1 can function through a receptor which activates intracellular components in the ras/raf/MEK/MAPK pathway.

Animals↗

PubMed1997

Expression of epidermal growth factor-related proteins in the aged adult mouse mammary gland and their relationship to tumorigenesis.

Mammary glands from female BALB/c mice of different ages and parity were screened for production of three epidermal growth factor (EGF) related transforming growth factors and their corresponding mRNAs. Glands were obtained from 2-26-month-old nulliparous, 4-26-month-old parous, and 2-8-month-old midpregnant mice. Reverse-transcribed polymerase chain reaction (RT-PCR) was used to screen for mRNA from the transforming growth factor alpha (TGF alpha), cripto-1 (CR-1), and amphiregulin (AR) genes in extracts of whole mammary glands. TGF alpha, CR-1, and AR transcripts were detected in all of the mammary glands assayed. In situ hybridization was then used to localize these mRNAs among various cell types in sections of glands. TGF alpha mRNA levels were low in the mammary epithelium from young nulliparous mice, high in the stroma of midpregnant mammary glands, and highest in luminal epithelium of the aged glands. AR mRNA levels were high and remained unchanged in all developmental stages. CR-1 mRNA level increased with age and was detected primarily in epithelium, with some scattered expression in adjacent stroma. Finally, TGF alpha, CR-1, and AR proteins were immunolocalized in histological sections of mammary glands from the various developmental stages. TGF alpha was detected sporadically in midpregnant mice, with more conspicuous reactivity seen in 18-26-month-old mice (38% of mice). CR-1 immunoreactivity was detected in 100% of the 18-26-month-old glands but not in any other age groups. Strong AR immunoreactivity was observed in in all glands, including 100% of the 18-26-month-old glands. Staining for all three of these growth factors was observed primarily in the epithelium, with some reactivity detected in the periductal fibroblasts. No significant difference was discerned between glands from nulliparous and parous animals. We also found intense CR-1 and AR mRNA expression and strong immunoreactivity in seven different carcinogen-induced and eight spontaneous mammary tumors. Our results demonstrate that these growth factors accumulate in significant amounts in the old gland of both nulliparous and parous mice. The observations suggest that these growth factors are positioned to contribute to abnormal development in the older mammary gland, predisposing them to tumorigenesis.

Aging↗

PubMed1997

c-erbB-3 protein expression in ductal carcinoma in situ of the breast.

c-erbB-3, A recently identified member of the type I tyrosine kinase receptor family, has been shown to be overexpressed in invasive ductal carcinoma of breast. In this study, expression of the c-erbB-3 protein was examined in 57 cases of pure ductal carcinoma in situ of the breast (DCIS) by immuno-cytochemical methods. Staining was either absent (17 cases), present at levels equivalent to that found in adjacent normal tissue (20) or greater than in normal tissue (20). In most cases the pattern of staining was cytoplasmic, but in 4 cases with the most intense reaction there was also focal membrane staining. In the same series of cases, c-erbB-2 protein had previously been shown to be overexpressed in 28 of 57 cases, c-erbB-2 overexpression was correlated with normal level of c-erbB-3, and lack of c-erbB-2 expression was correlated with c-erbB-3 overexpression.

Breast Neoplasms↗