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PubMed1994

Proteolytic cleavage of the integrin beta 4 subunit.

The integrin beta 4 subunit often undergoes proteolytic cleavage within its long cytoplasmic tail to yield a characteristic protein pattern of 205, 165, and 125 kDa. The results in this study suggest that beta 4 cleavage often occurs during or after cell lysis, where it was readily inhibitable by calcium chelators (EDTA, EGTA) and inhibitors of cysteine proteases (E64c, leupeptin). The cleavage of beta 4 is catalyzed by a calpain-like enzyme because (i) it requires calcium, (ii) it is mimicked by purified milli-calpain, and (iii) it is inhibited by several calpain inhibitors including the calpain-specific inhibitor calpastatin. Within intact cells, cleavage of beta 4 was cell type-specific and observed only when the cells were made permeable to calcium. Substantial cell viability was retained during beta 4 cleavage induced by ionomycin plus calcium, indicating that cleavage within intact cells was not necessarily a consequence of cell death. However, manipulations of cells including suspension, synchronization, and stimulation with serum, phorbol esters, or other agents all failed to induce cleavage, suggesting that if cleavage is physiologically relevant, it is not easily duplicated in vitro. Analysis of multiple cell types showed a wide variation in beta 4 sensitivity to proteolytic cleavage, suggesting that this process might be differentially regulated depending on the cellular environment.

Antigens, Surface↗
PubMed1997

Alpha 6 beta 4 and alpha 6 beta 1 integrins associate with ErbB-2 in human carcinoma cell lines.

Growth factors modulate integrin-mediated cell adhesion and motility, and their receptors are thought to share proteins that mediate intracellular signaling with integrin receptors. The crosstalk between these receptors is thought to play a relevant role in transformation and tumor progression. To highlight possible interactions between growth factors and cell adhesion receptors we investigated whether integrins associate with tyrosine kinase receptors in tumor cells. By affinity chromatography and Western blot analyses of purified immune complexes, we studied the association of laminin receptors (alpha 6 beta 1 and alpha 6 beta 4) with ErbB-2 tyrosine kinase in human carcinoma cell lines. We demonstrated that the alpha 6 beta 4 and alpha 6 beta 1 integrins coprecipitated with ErbB-2 in lysates from carcinoma or NIH3T3 cells overexpressing ErbB-2. Integrin-mediated activation of ErbB-2 receptors suggested that this association is functionally meaningful. Indeed, carcinoma cells treated with a monoclonal antibody to the alpha 6 integrin subunit showed a ligand-dependent increase of ErbB-2-phosphorylated molecules coprecipitated with integrins and an increased DNA synthesis. The interaction between growth factor receptors and integrins was also studied in NIH3T3 cells overexpressing alpha 6 beta 4 receptors and ErbB-2 protein. We report that cells overexpressing both receptors, but not those overexpressing a crippled ErbB-2, showed enhanced proliferation rates and invasiveness, further suggesting that alpha 6 beta 4 integrin and ErbB-2 receptor interaction might contribute to generate a more malignant phenotype in carcinoma cells.

3T3 Cells↗
PubMed2001

Laminin-10 mediates basal and EGF-stimulated motility of human colon carcinoma cells via alpha(3)beta(1) and alpha(6)beta(4) integrins.

Signals from the epidermal growth factor (EGF) receptor and integrin-dependent adhesion to laminin contribute to the progression and metastasis of colonic tumors. However, little is know about the mechanisms by which these signals cooperate. Recently, we have reported that the colon cancer cell line LIM1215 secretes and adhere to autocrine laminin-10 via multiple integrin receptors and that EGF stimulates spreading of these cells on the same substrate. In this report, we investigate the effect of EGF and laminin-10 on colon cancer cell migration in vitro. EGF stimulates migration of LIM1215 cells in a wound healing assay. The response to EGF is inhibited by anti-EGF receptor antibody 528, the EGF receptor kinase inhibitor AG-1478, or the MAP kinase kinase inhibitor PD98059 but not the PI3-K inhibitor wortmannin. Using Transwell migration chambers, we demonstrate that laminin-10 but not collagen-I, collagen-IV, or a commercial preparation of human placental laminin is a potent motility factor for LIM1215 cells. The migration response to laminin-10 is increased upon stimulation of the cells with EGF and correlates with the up-regulation of alpha(6)beta(4) integrin expression as measured by analysis of Triton X-100-soluble cellular extracts. The results from integrin inhibition experiments indicate that basal migration on laminin-10 is mediated by alpha(3)beta(1) but not alpha(2)beta(1) nor alpha(6)beta(4) integrins. Alpha(3) blocking antibodies also inhibited EGF-stimulated chemokinetic migration of LIM1215 cells on laminin-10. However, in contrast to unstimulated cells, alpha(6) or beta(4) integrin-blocking antibodies inhibited the migration of EGF-stimulated cells by up to 50%. Taken together, these results support the cooperative role of EGF receptor and laminin-10 on colon cancer cell motility and suggest a critical role for both the alpha(3)beta(1) and the alpha(6)beta(4) integrins in this process.

Actins↗
PubMed1993

Integrin beta 4 expression in the neoplastic progression of cervical epithelium.

Integrin alpha 6 beta 4, a putative laminin receptor, is expressed in normal squamous epithelium and in squamous cell carcinomas. We evaluated by immunohistochemistry the topography of the beta 4 subunit in 35 biopsy samples representative of the sequence from normal exocervical epithelium to invasive squamous cell carcinoma. In normal and metaplastic squamous cervical epithelium, in condylomas, and in squamous epithelium with low-grade dysplasia (CIN 1), beta 4 was detected in basal and parabasal cells. In high-grade CIN (2-3) there was enhanced beta 4 expression and upward shift of beta 4 topography to the whole epithelial thickness. The beta 4 chain was diffusely expressed in most invasive squamous cell carcinomas. These observations suggest that profound alterations in the expression of the alpha 6 beta 4 adhesion glycoprotein occur in the intraepithelial phase of cervical carcinogenesis.

Antigens, Neoplasm↗
PubMed2000

Reconstruction of protein form with X-ray solution scattering and a genetic algorithm.

We have reconstructed, from experimental approximately 2 nm resolution X-ray solution scattering profiles, the corresponding shapes and sizes of myoglobin, troponin C, spermadhesin PSP-I/PSP-II, chymotrypsinogen A, superoxide dismutase, ovalbumin, tubulin, nitrite reductase, catalase, the structural change of troponin C upon dissociation of the two high affinity Ca(2+), and the solution model structure of a tandem pair of fibronectin type III cytoplasmic domains of integrin alpha6beta4 before determination of its crystal structure. To this purpose we have designed a new genetic algorithm which gradually explores a discrete search space and evolves convergent models made of several hundred beads (down to 0.3 nm radius) best fitting the scattering profile upon Debye calculation, without geometrical constraints or penalty for loose beads. This is a procedure of effective numerical transformation of the one-dimensional scattering profiles into three-dimensional model structures. The number of beads in models is correlated with the protein molecular mass (with one exception). The shape and approximate dimensions of each protein have been retrieved by a set of ten solution models, essentially superimposable with the available crystal structures.

Algorithms↗
PubMed2001

Towards a mechanistic understanding of tumor invasion--lessons from the alpha6beta 4 integrin.

This review explores the mechanistic basis of carcinoma migration and invasion by focusing on the contribution of integrins. Integrins are essential for invasion not only for their ability to mediate physical interactions with extracellular matrices, but also for their ability to regulate signaling pathways that control actin dynamics and cell movement, as well as for growth and survival. Our comments center on a unique member of the integrin family, the alpha 6 beta 4 integrin, which is a receptor for the laminin family of basement membrane components. Numerous studies have implicated this integrin in the invasion of solid tumors and have provided a rationale for studying the mechanistic basis of its contribution to the invasive process. Such studies have revealed novel insights into the mechanism of carcinoma invasion that involve both the dynamics of cell migration and signaling pathways that regulate this migration.

Antigens, Neoplasm↗
PubMed1993

Specific alterations in the expression of alpha 3 beta 1 and alpha 6 beta 4 integrins in highly invasive and metastatic variants of human prostate carcinoma cells selected by in vitro invasion through reconstituted basement membrane.

Highly invasive cell subpopulations from a human prostate carcinoma cell line, PC-3, were selected for by allowing the parental PC-3 cells to invade through reconstituted basement membrane, Matrigel. These cells were collected, cultured and then selected further by repeated invasion through the in vitro invasion chamber. The invasive subpopulations (I-PC3 (2) and (3)) were found to be approximately 15-fold more invasive in vitro than the parental cells, had a distinct rounded morphology in culture, and proliferated more rapidly than the parental cells. When injected either subcutaneously or intraperitoneally into immunocompromised SCID mice, the I-PC3 cells were found to form tumors at the primary sites and to be highly invasive and metastatic. In contrast, the parental PC-3 cells formed tumors at the site of inoculation in these mice but failed to invade or metastasize. The I-PC3 cells attached equally as well as PC-3 cells to fibronectin, laminin, collagen type IV and vitronectin, but unlike the parental PC-3 cells these invasive variants failed to spread on any of these substrates. On Matrigel, the PC-3 cells became highly organized, whereas the I-PC3 cells remained rounded, clumped together and penetrated into the Matrigel. Biochemical analysis of the expression of adhesion proteins and integrins demonstrated that whereas the parental cells synthesized and secreted substantial amounts of fibronectin, the I-PC3 cell variants did not secrete any fibronectin. Although both PC-3 and I-PC3 cells expressed equivalent levels of cell surface alpha v beta 3, alpha 2 beta 1 and alpha 5 beta 1 integrins, the expression of the alpha 3 beta 1 integrin, which is expressed at very high levels on the parental PC-3 cells, was drastically reduced on the invasive I-PC3 cells. This decrease in expression of alpha 3 occurred also at the level of mRNA expression. Finally, whereas the PC-3 cells express alpha 6 beta 1, in the invasive I-PC3 cells the alpha 6 subunit was associated mostly with the beta 4 subunit. Since the alpha 6 beta 4 integrin is analogous to the A9 tumor antigen which is associated with aggressive human squamous cell carcinomas, the apparent overexpression of alpha 6 beta 4 may also participate in the aggressive behavior of these variant prostate carcinoma cells. Alterations in the expression of the alpha 3 beta 1 and alpha 6 beta 4 integrins may thus allow these cells to become more invasive, and lead to an increased propensity for metastasis.

Antigens, Surface↗
PubMed1996

The molecular basis for inherited bullous diseases.

In the past 5 years enormous progress have been made in our understanding of the molecular basis for a number of inherited skin diseases characterized by easy blistering of the skin and the mucous membranes after minor physical trauma. This increased fragility of the skin or its appendages is due to molecular defects in genes coding for different intra- and extracellular structural proteins which are responsible for mechanical strength at their sites of expression. These diseases encompass the group of epidermolysis bullosa and disorders of cornification such as bullous forms of ichthyosis, palmoplantar keratoderma, and pachyonychia congenita. On the basis of clinical, morphological, and ultrastructural observations the epidermolysis bullosa group has been divided into three major categories. In epidermolysis bullosa simplex blister formation appears within the basal cell layer of the epidermis, and many mutations have been found in the genes of keratin 5 and 14 which are both expressed in basal keratinocytes. Epidermolytic hyperkeratosis leads to an epidermal separation in the suprabasal cell layers. In these patients numerous point mutations have now been described in the suprabasally expressed genes of keratin 1 and 10. In ichthyosis bullosa of Siemens blisters occur in the more upper suprabasal epidermis coincidental with the expression of keratin 2e, and mutations have been detected in the corresponding gene. In epidermolytic palmoplantar hyperkeratosis the suprabasal epidermal splitting is restricted to palms and soles of the patient. In keratin 9, which reveals such an exclusive expression pattern, molecular defects have indeed been recognized. Most recently in two different clinical subtypes of pachyonychia congenita, which is characterized by defective nails and focal palmoplantar hyperkeratosis, point mutations have been found in the genes coding for keratins 6, 16, and 17. In junctional epidermolysis bullosa the separation takes place within the dermal-epidermal basement membrane at the level of the lamina lucida, and mutations have been found in three genes coding for different laminin chains, in the beta4 gene of alpha6beta4 integrin, and in the gene of collagen XVII. In dystrophic epidermolysis bullosa the tissue separation occurs beneath the basement membrane within the papillary dermis at the level of the anchoring fibrils, and several mutations have been identified in the collagen VII gene. The rapid unraveling of molecular defects in these disabling or even lethal inherited skin diseases makes possible a more precise and earlier prenatal diagnosis, creates new options for suitable therapeutic regimens, and even offers the hope of curing these diseases by means of somatic cell gene therapy.

Antigens, CD↗
PubMed1995

The alpha 6 beta 1 and alpha 6 beta 4 integrins in human prostate cancer progression.

Prostatic secretions are formed by glands composed of basal and luminal cells and surrounded by a basal lamina. The normal basal cells express several integrins (extracellular matrix receptors) including alpha 2, 3, 4, 5, 6, v, beta 1 and beta 4. These integrin units are polarized at the base of the cells adjacent to the basal lamina. The integrin alpha 6 beta 4 is associated with hemidesmosomal-like structures. The natural history of prostate cancer involves the presence of prostatic intraepithelial neoplasia (PIN) lesions (considered precursor lesions), carcinoma in situ and invasive carcinoma. Hemidesmosomal proteins and the alpha 3 beta 1 and alpha 6 beta 1 integrins (laminin receptors) are retained in the early PIN lesions. Expression of the integrins alpha 2, alpha 4, alpha 5, alpha v and beta 4 is lost in carcinoma. The alpha 3 beta 1 and alpha 6 beta 1 integrins remain associated with invasive carcinoma, the latter being predominant. Integrin expression in carcinoma is diffuse in the plasma membrane and not restricted to the basal aspects of the cell. The alpha 6 beta 1 integrin is fully functional as judged by an ability to adhere to laminin and contains the wild type alpha 6A cytoplasmic signaling domain. The alpha 6 beta 1 integrin is a leading candidate for conferring the invasive phenotype in prostatic carcinoma. Tumor cells with high expression of alpha 6 integrin are more invasive when tested in a SCID mouse model system. Following intraperitoneal injection, the human tumor cells invade the mouse diaphragm and move through the muscle on the surface of the laminin coated muscle cells. Our current working hypothesis is that the production of alpha 6 beta 1 and laminin in human tumor cells contributes to the invasive phenotype. Invasion could occur on the surfaces of laminin coated structures such as the nerves, blood vessels or muscle and account for the known patterns of human prostate tumor progression. Blockage of the expression or function of alpha 6 beta 1 or laminin or preventing the loss of beta 4 would be essential steps in confining the carcinoma to the prostate gland where conventional treatment has already proven effective.

Amino Acid Sequence↗
PubMed1997

The distribution of alpha 2 beta 1, alpha 3 beta 1 and alpha 6 beta 4 integrins identifies distinct subpopulations of basal keratinocytes in the outer root sheath of the human anagen hair follicle.

The human hair follicle is composed of different concentric compartments, which reflect different programmes of differentiation. Using monoclonal antibodies against alpha 2 beta 1 and alpha 3 beta 1 integrins we demonstrated a shift in their expression, from a basolateral distribution in the basal cells of the lower outer root sheath, to an apicolateral expression in the upper outer root sheath, as in epidermis. This shift takes place in a transition zone, localized to the midpart of the follicle. The distinct basolateral distribution of alpha 2 beta 1 and alpha 3 beta 1 integrins in the lower portion of the outer root sheath coincides with the presence of basal cell protrusions and is probably linked to the presence of the vitreous membrane which surrounds the bottom part of the anagen human hair follicle. Moreover, we showed that the expression of alpha 6 beta 4 integrin is discontinuous along the hair follicle and coincides with that of laminin 5. Together these results establish that within a given compartment-namely the outer root sheath-several domains can be clearly identified, which probably reflect the onset of successive differentiation pathways along the hair follicle.

Antigens, Surface↗
PubMed2001

Reconstruction of basement membrane in skin equivalent; role of laminin-1.

To reconstruct the basement membrane in a skin equivalent, the epidermodermal interface was coated with porcine type IV collagen and mouse laminin-1 at various ratios before keratinocyte seeding. Laminin-1, a component of the basement membrane, induced massive infiltration of keratinocytes into the dermal equivalent, while type IV collagen induced discrete demarcation between dermal and epidermal compartments without any infiltrating cells. Immunohistochemical staining indicated that the laminin-induced infiltrating cells expressed endogenous type IV collagens at the cell periphery, which were not incorporated into the basement membrane structure. The infiltrating cells did not express fibronectin receptor alpha5beta1 integrin but showed MMP-9 secretion and cell surface associated MMP-2. However, when laminin-1 was preincubated with type IV collagen, laminin-1-induced keratinocyte infiltration as well as MMP-9 induction were almost completely suppressed to basal levels. Therefore, replenishment of the type IV collagen lattice seemed to cause laminin-stimulated cells to anchor to the lattice, in a similar manner to the basal cells on the basement membrane of normal skin. Our study suggests that the molar ratio of basement membrane components may determine the behavior of basal cells within the wound healing microenvironment, which is probably regulated either by extracellular matrix deposition or degradation.

3T3 Cells↗
PubMed2001

Metastatic growth of squamous cell carcinomas is correlated with upregulation and redistribution of hemidesmosomal components.

Bullous pemphigoid antigen-1 (BPA1) and alpha(6)beta(4)-integrin colocalize at the hemidesmosomes in basal-layer keratinocytes of normal squamous epithelia. The expression of these genes was analyzed during the process of tumor cell invasion and metastasis on frozen sections of head and neck biopsies, and the structural appearance of hemidesmosomes was analyzed by electron microscopy. Despite a diminution of hemidesmosomal structures as revealed by electron microscopy, gene expression of BPA1 and alpha(6)beta(4)-integrins was distinctly upregulated with the onset of invasive growth, demonstrated at the mRNA level by in situ hybridization. The upregulated gene expression extended to the entire proliferative zone of invasive tumors, including the tumor cells which have lost contact with the basement membrane and no longer display hemidesmosomes. The polarized localization of the BPA1 and alpha(6)beta(4) proteins to the basal aspect of the peripheral tumor cells was largely retained in invasive but nonmetastatic lesions, but was lost upon progression to metastatic growth of head and neck squamous cell carcinomas (SCC), in which pericellular staining extended into many tumor cell layers. The results of this study confirm that expression of BPA1 and alpha(6)beta(4)-integrins is elevated in carcinoma cells but is not directed to intact hemidesmosomes. Importantly, this loss of directed localization is an indicator of the capacity to metastasize.

Antigens, Surface↗
PubMed2005

Mobilization and activation of a signaling competent alpha6beta4integrin underlies its contribution to carcinoma progression.

This review examines the hypothesis that the function of the alpha 6beta 4 integrin is altered substantially as normal epithelia undergo malignant transformation and progress to invasive carcinoma and that the functions of this integrin contribute to the behavior of aggressive carcinoma cells. Specifically, alpha 6beta 4 functions primarily as an adhesion receptor in normal epithelia, often as a component of hemidesmosomes and associated with intermediate filaments. Factors in the host-tumor microenvironment have the potential to mobilize alpha 6beta 4 from hemidesmosomes and promote its association with F-actin in lamellae and filopodia, a process that is mediated by PKC-dependent phosphorylation of the beta 4 cytoplasmic domain. Importantly, this altered localization of alpha 6beta 4 appears to be coupled to an activation of its signaling potential, which may occur through its association with growth factor receptors or lipid rafts, possibilities that are not mutually exclusive. The primal signaling event triggered by alpha 6beta 4 appears to be activation of PI3-K and this activation has profound consequences on the migration, invasion and survival of carcinoma cells. Arguably, the ability of alpha 6beta 4 to stimulate the PI3-K-dependent translation of VEGF and possibly other growth factors may be the most significant contribution of this integrin to carcinoma because of the potential autocrine and paracrine effects of these factors.

Actins↗
PubMed1992

Expression of alpha 6 beta 4 integrin increases during malignant conversion of mouse epidermal keratinocytes: association of beta 4 subunit to the cytokeratin fraction.

The expression of alpha 6 beta 4 integrin has been analyzed in several keratinocyte cell lines representative of various stages of mouse epidermal carcinogenesis. The immunological analyses carried out show that alpha 6 beta 4 is expressed at the cell surface of the cell lines which exhibit an epithelial or epithelioid morphology. The relative levels of alpha 6 beta 4 expressed at the cell surface increase noticeably from premalignant to malignant cells, as detected by fluorescence flow cytometry. This increase also correlates with the abundance of soluble beta 4 subunit detected by Western immunoblotting in the different cell lines. However, complete absence of alpha 6 beta 4 has been found in spindle carcinoma cells showing a fibroblast-like phenotype in culture. The integrin remains associated to detergent- and high salt-insoluble cytoskeletal components, organized in stable anchoring contacts, as in human keratinocytes (Carter et al., J. Cell Biol., 111, 3141, 1990). In addition, a significant fraction of the beta 4 subunit is detected associated to highly purified cytokeratin fractions. These results, together with those regarding the organization of both cellular components in drug-treated cells, support the existence of a close association between alpha 6 beta 4 and the intermediate filaments of the cytoskeleton.

Animals↗
PubMed1995

The alpha 6-integrin receptor in pancreatic carcinoma.

BACKGROUND/AIMS: The alpha 6-containing integrin was suggested to be involved in the process of tumor invasion and metastasis. Therefore, the aim of the study was to investigate the expression and function of this adhesion receptor in pancreatic carcinoma. METHODS: Integrin expression was investigated in pancreatic tissue and tumor cell lines using immunohistochemistry. Radioimmunoprecipitation was used to determine the complex composition of alpha 6. To analyze the function of the alpha 6-containing integrin in pancreatic cancer, in vitro adhesion, migration, and invasion experiments were performed. RESULTS: The alpha 6-containing integrin was differentially expressed in normal pancreas and pancreatic carcinoma. Immunoprecipitation of different pancreatic carcinoma cell lines showed that alpha 6 was expressed together with the beta 4 subunit as alpha 6 beta 4 complex. However, adhesion of pancreatic cancer cells to laminin could be inhibited with anti-alpha 6 and anti-beta 1 integrin antibodies but not by anti-beta 4 integrin antibody. Migration of the cells through laminin was almost completely inhibited by anti-beta 1 antibody but not by other anti-integrin antibodies. Tumor cell invasion through a reconstituted basement membrane was only slightly inhibited by anti-alpha 6 antibody. In contrast, a marked inhibition was observed using anti-beta 1 antibodies, anti-alpha 2-anti-alpha 5 antibodies, and RGDS. CONCLUSIONS: The alpha 6-containing integrin is a laminin adhesion receptor in pancreatic carcinoma cells, possibly involved in tumor invasion through the basement membrane.

Antigens, Surface↗
PubMed1992

Integrins and their accessory adhesion molecules in mammary carcinomas: loss of polarization in poorly differentiated tumors.

The integrins are alpha beta heterodimeric transmembrane proteins mediating cell-substratum as well as cell-cell interactions. To identify the pattern of expression of the beta 1, beta 3, and beta 4 integrins and their accessory adhesion molecules in relation to the malignant phenotype of invasive breast cancer, we performed an immunohistochemical study for the alpha 2 beta 1 (VLA-2), alpha 6 beta 1 (VLA-6), alpha v and alpha v beta 3 (vitronectin receptor), alpha 6 beta 4, carcinoembryonic antigen, and carcinoembryonic antigen-related molecules in a series of 37 invasive breast carcinomas. All integrin chains examined showed similar patterns in nonneoplastic breast tissue, with strong membrane staining of the myoepithelial cells and weak to moderate staining on the basolateral surfaces of the luminal cells. We found that downregulation of the alpha 2 chain of VLA-2 occurs more frequently in poorly differentiated grade III invasive ductal carcinomas (IDCs) (P = .048). Loss of alpha 6 beta 4 seems also to occur more frequently in grade III IDC (seven of 11 cases, 63.6%) than in grade I/II IDC (two of eight cases, 25%), although this did not reach statistical significance. Carcinoembryonic antigen and carcinoembryonic antigen-related antigens, which are known to function as accessory adhesion molecules, were found mainly in the cytoplasm of neoplastic cells and there was reduced membrane polarization in poorly organized tumors. In contrast the alpha v beta 3, vitronectin receptor heterodimer recognized by the 23C6 monoclonal antibody was weak or absent in normal breast epithelium, and was weakly expressed in two of 19 (10%) IDCs and in nine of 18 (50%) invasive lobular carcinomas (P = .008). However, the alpha v chain detected with the antibody 13C2 was weakly to moderately expressed on nonneoplastic epithelium and at a similar intensity in 13 of 19 IDCs and 15 of 17 invasive lobular carcinomas, suggesting that in IDC the alpha v chain may be associated with a different beta chain (possibly beta 1 or beta 5). No correlation between integrin expression and estrogen/progesterone receptor status was found. These data provide further evidence that in invasive breast carcinomas there is a widespread deregulated expression of integrins and their accessory adhesion molecules with loss of polarization. Changes in the expression and function of cell adhesion molecules, which control growth and differentiation, may have clinical relevance in the behavior of breast cancer.

Antigens, Surface↗