TGF alpha and TGF beta expression in mammary carcinoma

Antisense Oligonucleotides Targeting Angiogenic Factors as Potential Cancer Therapeutics

Cancer is one of the leading causes of death worldwide, and conventional cancer therapies such as surgery, chemotherapy, and radiotherapy do not address the underlying molecular pathologies, leading to inadequate treatment and tumor recurrence. Angiogenic factors, such as EGF, PDGF, bFGF, TGF-β, TGF-α, VEGF, endoglin, and angiopoietins, play important roles in regulating tumor development and metastasis, and they serve as potential targets for developing cancer therapeutics. Nucleic acid-based therapeutic strategies have received significant attention in the last two decades, and antisense oligonucleotide-mediated intervention is a prominent therapeutic approach for targeted manipulation of gene expression. Clinical benefits of antisense oligonucleotides have been recognized by the U.S. Food and Drug Administration, with full or conditional approval of Vitravene, Kynamro, Exondys51, and Spinraza. Herein we review the scope of antisense oligonucleotides that target angiogenic factors toward tackling solid cancers.

Therapy-induced apoptosis in primary tumors

An enormous body of literature has accumulated over the past 15 years implicating apoptosis (programmed cell death) in breast cancer cell death induced by conventional and investigational cancer therapies in preclinical models. As a result, new therapeutic approaches that directly target key components of apoptotic pathways are either entering or will soon enter clinical trials in patients, raising hopes that the information gained from the preclinical studies can be translated to improve patient care. However, there is a new appreciation for the fact that apoptosis is not the only relevant pathway that mediates physiological cell death, and many investigators are challenging the notion that targeting apoptosis is the best means of optimizing therapeutic efficacy in primary tumors. Here I will review some of the basic concepts that have emerged from the study of apoptosis in preclinical models, the evidence that apoptosis does or does not mediate the effects of current front line therapies in patients, and the new strategies that are emerging that are designed to more directly target apoptotic pathways.

Determination of TGFbeta1 protein level in human primary breast cancers and its relationship with survival

Transforming growth factor-beta (TGFbeta)1 is thought to be implicated in breast cancer progression. However, data about the influence of TGFbeta1 on breast cancer development are conflicting. To clarify the clinical relevance of TGFbeta1, TGFbeta1 protein level has been measured by enzyme-immunoassay in 193 breast tumour samples. We found that 94.3% of patients expressed TGFbeta1 with a range of 0-684 pg mg(-1) protein. In the overall population, an increase of tumoral TGFbeta1 was observed in premenopausal patients when compared to postmenopausal subgroup (P=0.0006). When patients were subdivided according to nodal status, TGFbeta1 was correlated to type-1 plasminogen activator inhibitor in the node-negative subgroup (P=0.040). Multivariate analysis revealed that, after lymph node status (P=0.0002) and urokinase-type plasminogen activator (P=0.004), TGFbeta1 was an independent prognostic marker for DFS (P=0.005) in the overall population. In the node-negative population, TGFbeta1 was the prominent prognostic factor (P=0.010). In the same population, Kaplan-Meier curves demonstrated that high TGFbeta1 level was correlated with a shorter disease-free survival (P=0.020). These data suggest that the measurement of tumoral TGFbeta1 protein level, especially for node-negative patients, might help to identify a high-risk population early in tumour progression.

The not-so innocent bystander: the microenvironment as a therapeutic target in cancer

The microenvironment in which cancer arises is often regarded as a bystander to the clonal expansion and acquisition of malignant characteristics of the tumour. However, a major function of the microenvironment is to suppress cancer, and its disruption is required for the establishment of cancer. In addition, tumour cells can further distort the microenvironment to promote growth, recruit non-malignant cells that provide physiological resources, and facilitate invasion. In this review, the authors discuss the contribution of the microenvironment, i.e., the stroma and its resident vasculature, inflammatory cells, growth factors and the extracellular matrix (ECM), in the development of cancer, and focus on two components as potential therapeutic targets in breast cancer. First, the ECM, which imparts crucial signalling via integrins and other receptors, is a first-line barrier to invasion, modulates aggressive behaviour and may be manipulated to provide novel impediments to tumour growth. Second, the authors discuss the involvement of TGF-beta1 as an example of one of many growth factors that can regulate ECM composition and degradation and that play complex roles in cancer. Compared to the variable routes taken by cells to become cancers, the response of tissues to cancer is relatively consistent. Therefore, controlling and eliminating cancer may be more readily achieved indirectly via the tissue microenvironment.

Guanosine nucleotides inhibit different syndromes of PTHrP excess caused by human cancers in vivo

There are two well-described syndromes caused by tumor production of parathyroid hormone-related peptide (PTHrP), namely osteolytic bone disease associated with breast cancer and humoral hypercalcemia of malignancy (HHM) that occurs with or without bone metastasis. Both syndromes have been shown experimentally to be inhibited by neutralizing antibodies to PTHrP. In a search for small-molecule inhibitors of PTHrP production or effects, we have identified guanine-nucleotide analogs as compounds that inhibit PTHrP expression by human tumor cells associated with these syndromes. We show in nude athymic murine models that these compounds reduce PTHrP-mediated osteolytic lesions associated with metastatic human breast-cancer cells as well as the degree of hypercalcemia caused by excessive PTHrP production by a squamous-cell carcinoma of the lung. These results suggest that the PTHrP gene promoter may be a suitable target for treating the skeletal effects of malignancy.

Co-expression of epidermal growth factor receptor and transforming growth factor-alpha predicts worse prognosis in breast-cancer patients

Epidermal growth factor receptor (EGF-R) and its ligand, transforming growth factor-alpha (TGF-alpha), play an important role through the autocrine growth-regulation system in several human cancers, including breast cancer. However, the clinical significance of co-expression of EGF-R and TGF-alpha has not been elucidated. One hundred seventy-three female patients diagnosed as invasive ductal carcinoma who had undergone a mastectomy (159 patients) or breast-conserving surgery (14 patients) were followed up for 81 to 119 months (median 94 months) post-operatively. Immunoreactivity for EGF-R, TGF-alpha, p53 and c-erbB-2 with paraffin-embedded carcinoma tissue was investigated using labeled streptavidin-biotin methods. Positive rates of carcinoma cells were 27%, 33%, 32% and 26% for EGF-R, TGF-alpha, p53 and c-erbB-2, respectively. Expression of EGF-R only was observed in 16% (28/173), of TGF-alpha only in 22% (38/173), of both EGF-R and TGF-alpha in 11% (19/173) and of neither in 51% (88/173). By univariate analysis, significant differences in overall survival and disease-free survival were noted according to the co-expression of EGF-R and TGF-alpha (p< 0.0001, p<0.0001), co-expression of EGF-R and c-erbB-2 (p = 0.0029, p = 0.0028), nodal status (p = 0.0028, p = 0.0001), tumor size (p = 0.0001, p<0.0001) and c-erbB-2 expression (p = 0.0034, p = 0.018), respectively. The status of p53 expression (p = 0.01), estrogen receptor (p = 0.042) and progesterone receptor (p = 0.046) showed significant differences in overall survival. According to Cox's multivariate analysis, co-expression of EGF-R and TGF-alpha had the most significant effect on disease-free survival (p<0.0001) and overall survival (p<0.0001), followed by nodal status. Co-expression of EGF-R and TGF-alpha by immunohistochemical detection is an independent prognostic indicator, and it may be helpful for determining the group of breast-cancer patients with an aggressive phenotype.

Use of specimen mammography-guided FNA (fine-needle aspirates) for flow cytometric multiple marker analysis and immunophenotyping in breast cancer

A pilot study of a novel translational research method to simultaneously assay multiple molecular markers and DNA in fine-needle aspirates (FNA) of mammographically detected breast lesions is described. Specimen mammography-guided 20-gauge FNAs obtained from 86 lesions and 22 areas of normal tissue were analyzed by multiparameter flow cytometry for DNA content, her2/neu, transforming growth factor alpha (TGF alpha), and the epithelial marker cytokeratin (CK) simultaneously. Epithelial cell her2/neu positivity was detected in 12 of 44 (27%) of invasive ductal carcinomas and 3 of 9 (33%) ductal carcinoma in situ (DCIS), 10 of 30 (33%) benign lesions, and 4 of 22 (18%) normal tissue aspirates. All lesions and normal tissue showed a similar positive rate for TGFalpha ranging from 61 to 76%. The CK(+)TGF alpha(-)her2/neu(+) immunophenotype was more frequently positive in aneuploid tumors (22%) than all other lesions (7%) (P < 0.05). Specimen mammography-guided FNAs provide fresh cells for flow cytometric multiple marker analysis and immunophenotyping of clinically occult breast lesions and normal tissue.

Loss of expression of transforming growth factor beta type II receptor correlates with high tumour grade in human breast in-situ and invasive carcinomas

AIMS

Loss of transforming growth factor beta type II receptor (TGFbeta-RII) expression has been associated with resistance to TGFbeta-mediated inhibition of cell proliferation and tumour progression. We investigated whether the expression of TGFbeta-RII is related to the progression of human breast cancer and whether there is a correlation between TGFbeta-RII expression and phenotypic markers of biological aggressiveness.

METHODS AND RESULTS

Immunohistochemical methods were used to detect TGFbeta-RII in archival breast samples including benign proliferative lesions, ductal carcinoma in situ (DCIS) and invasive mammary carcinomas (IMC). Neoplastic cells showed reduced expression of TGFbeta-RII in comparison to the normal breast tissue and benign lesions. There was a significant inverse correlation between loss of TGFbeta-RII expression and tumour grade within both DCIS (P = 0.004) and IMC (P = 0.001) groups. There was an inverse correlation between TGFbeta-RII expression and both mitotic count (P = 0.001) and clinical stage (P = 0.004). Oestrogen receptor (P = 0.07) and lymph node status (P = 0.10) were not significantly associated with TGFbeta-RII expression.

CONCLUSIONS

These data indicate that decreased expression of TGFbeta-RII may contribute to breast cancer progression and is related to a more aggressive phenotype in both in-situ and invasive carcinomas.

Abordagem clínico-laboratorial no diagnóstico diferencial de hipercalcemia

A hipercalcemia é anormalidade metabólica comum, porém pouco diagnosticada por ser freqüentemente assintomática. Aproximadamente 90% dos casos são decorrentes de hiperparatireoidismo primário (HPT) ou doença maligna complicada por hipercalcemia, estando prevalentes em pacientes ambulatoriais e hospitalizados, respectivamente. Laboratorialmente, o HPT e hipercalcemia humoral maligna apresentam algumas semelhanças, tais como: aumento do AMPc nefrogênico, hipofosfatemia e hipercalciúria. Porém, o quadro clínico da hipercalcemia associada à malignidade é mais severo e, geralmente, o paciente apresenta-se clinicamente debilitado pela doença, com múltiplas metástases. A dosagem sérica de PTH intacto (PTHi) é fundamental para o diagnóstico definitivo, estando o PTHi elevado ou normal no HPT primário, e suprimido na malignidade. Os mecanismos de hipercalcemia da doença maligna são: secreção de fatores humorais que alteram a homeostase do cálcio e fatores locais produzidos pelos tumores metastáticos ou hematológicos no osso, causando aumento da reabsorção osteoclástica. A proteína relacionada ao hormônio da paratireóide (PTHrP) tem sido implicada na maioria dos casos de hipercalcemia devido a tumores sólidos. Outros fatores como interleucina-6, fator de crescimento tumoral, fator de necrose tumoral e interleucina-1 podem modular os efeitos do PTHrP nos órgãos-alvo, e em alguns tumores, ativam diretamente o osteoctastos como por exemplo no mieloma múltiplo. A hipercalcemia pode estar menos freqüentemente associada a algumas doenças endócrinas como tireotoxicose, feocromocitoma, doença de Addison e neoplasia endócrino múltipla tipos I e IIA. Algumas drogas podem causar esse distúrbio metabólica, merecendo destaque a vitamina D, os diuréticos tiazídicos e o lítio. A sarcoidose é exemplo de doença granulomatosa que pode associar-se à hipercalcemia em 10% dos casos e hipercalciúria em 50%. O diagnóstico diferencial das hipercalcemias é essencial para que haja uma abordagem terapêutica eficaz dessa anormalidade metabólica.

Expression of growth factors, growth inhibiting factors, and their receptors in invasive breast cancer. I: An inventory in search of autocrine and paracrine loops

The aim of the present study was to investigate which growth factors, receptors, and growth inhibiting factors are expressed in invasive breast cancer. Five (angiogenic) growth factors and their receptors: platelet-derived growth factor A chain (PDGF-AA) and PDGF receptor alpha (PDGF alpha R), PDGF-BB and PDGF beta receptor, transforming growth factor alpha (TGF alpha) and its receptor epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) and its receptors vascular endothelial growth factor receptor I (Flt-1) and vascular endothelial growth factor receptor II (Flk-1/KDR); two growth inhibiting factors: transforming growth factor-beta-1 (TGF beta 1) and (TGF beta 2) and their receptor couple transforming growth factor beta receptor I (TGF beta R-I) and TGF beta R-II; and basic fibroblast growth factor (bFGF) were stained by standard immunohistochemistry on frozen sections in 45 cases of invasive carcinoma of the breast. Staining was scored as negative or positive in tumour epithelium, stroma, and blood vessels. TGF beta 1 and TGF beta 2 were expressed in the tumour cells in 67 per cent and 76 per cent of cases, respectively, whereas PDG beta R and TGF beta R-II were expressed in 0 per cent and 2 per cent, respectively. The other factors showed variable expression in tumour cells. All factors were expressed in the stroma in most cases, except Flt-1, Flk-1/KDR, TGF beta 2, and TGF beta R-II, which showed variable expression, and EGFR, which showed no expression. The endothelium was in most cases positive for bFGF, PDGF-AA, PDGF-BB, VEGF, PDGF alpha R, PDGF beta R, and TGF beta 1 but TGF beta/ was negative in most cases and TGF alpha, EGFR, Flt-1, Flk-1/KDR, TGF beta R-I, and TGF beta R-II were variably expressed. The most interesting possible auto/paracrine loops, as demonstrated on serial sections and by fluorescence double staining, were the TGF alpha/EGFR, TGF beta s/TGF beta R, VEGF/Flt-1, and the VEGF/Flk-1 combinations. In conclusion, growth factors, growth inhibiting factors, and their receptors are frequently expressed in invasive breast cancer. Indications for some possible auto- and paracrine loops have been found, which should encourage further study on the role of these factors in breast cancer proliferation and angiogenesis.

Prolactin is an antagonist of TGF-beta activity and promotes proliferation of murine B cell hybridomas

Prolactin (PRL) is an immunomodulator that has been demonstrated to enhance immune responses both in vitro and in vivo. Prolactin enhances the proliferative response of lymphoid cells to both nonspecific mitogens and specific antigens and increases their production of IL-2 and interferon-gamma. Studies were performed to examine whether recombinant human prolactin (r-hPRL) also acts as a growth factor for B cell hybridomas. Prolactin was able to stimulate proliferation of murine B cell hybridomas in a dose-dependent manner and enhanced their proliferation in response to IL-4, IL-5, and IL-6. This increase in proliferation resulted in an overall increase in antibody production. Studies were also undertaken to examine the effect of PRL with transforming growth factor beta (TGF-beta), an immunosuppressive cytokine. Hybridoma cell lines incubated with TGF-beta demonstrated a dose-dependent decrease in proliferation. Variability in the degree of inhibition was observed among the various hybridomas in their responsiveness to TGF-beta. The addition of r-hPRL to the cultures reversed the antiproliferative effects of TGF-beta. The mechanism by which PRL can overcome the anti-proliferative effect of TGF-beta is under investigation. These findings provide an additional rationale for using r-hPRL clinically in immunosuppressed patients in certain disease settings such as AIDS and cancer, where overexpression of TGF-beta has been implicated in disease development and progression.

Transforming growth factor-beta1 enhances the invasiveness of human MDA-MB-231 breast cancer cells by up-regulating urokinase activity

Transforming growth factor-beta (TGFbeta1) enhances human MDA-MB-231 breast tumour cell invasion of reconstituted basement membrane in vitro but does not inhibit proliferation of this cell line. In contrast to basal invasion, which is plasmin-, urokinase (uPA)-, tissue-type plasminogen activator (t-PA)-, matrix metalloproteinase (MMP)-9- and TIMP-1-inhibitable MMP-dependent, TGFbeta1 enhanced-invasion is dependent upon plasmin and uPA activity but does not appear to involve t-PA-, MMP9- or TIMP-1-inhibitable MMPs, as judged by inhibitor studies. Enhanced invasion is associated with increased u-PA, UPAR, PAI-1, MT-MMP-1, MMP-9 and TIMP-1 expression; with reduced t-PA, MMP-1 and MMP-3 expression; and with the induction of membrane MMP-9 association. The net result of these changes includes increased secreted, but not membrane-associated, uPA levels and activity and reduced secreted levels of plasmin and APMA-activatable gelatinolytic, collagenolytic and caseinolytic MMP activity but no change in membrane-associated gelatinolytic activity, despite increased MT-MMP-1 expression and MMP-9 membrane association. TGFbeta1 does not induce MMP-2 expression. Our data indicate that TGFbeta1 can promote the malignant behaviour of MDA-MB-231 cells refractory to TGFbeta1-mediated proliferation control by enhancing their invasive capacity. We suggest that this results from the action of a uPA/plasmin-dependent mechanism resulting from stimulation of uPA expression, secretion and subsequent activity, despite elevated PAI-1 inhibitor levels.

Transforming growth factor alpha immunoreactivity in human gallbladder and extrahepatic biliary tract tumours

AIMS

Transforming growth factor alpha (TGF-alpha), a protein structurally similar to epidermal growth factor (EGF), is implicated in the development of many human tumours. This study examines the expression of TGF-alpha in gallbladder and extrahepatic biliary tract tumours in which EGFR expression has been previously shown to be important.

METHODS

A monoclonal antibody to the TGF-alpha protein was used to investigate the immunohistochemical expression of TGF-alpha in carcinoma of the gallbladder (n = 13), common bile duct (CBD) (n = 6) and ampulla of Vater (n = 8). Tissues from cases of chronic cholecystitis (n = 11), gallbladder dysplasia (n = 3) and adenoma (n = 1), and ampullary carcinoma in situ (CIS) (n = 3) were used as non-malignant controls. These cases were previously studied for EGFR expression.

RESULTS

TGF-alpha overexpression, defined as intense immunoreactivity in more than two-thirds of cells immunostained for TGF-alpha, was present in most gallbladder carcinomas (n = 10; 77%) but with no significant differences in expression between different tumour grades. None of the cases of gallbladder dysplasia or chronic cholecystitis had strong TGF-alpha expression and this was significantly different from the carcinomas (P = 0.013 and P = 0.0001, respectively; chi 2 test), although a few cases of chronic cholecystitis showed weak (n = 4), moderate (n = 6) or no (n = 1) immunoreactivity. A few ampullary carcinomas (n = 2; 25%) and CIS (n = 1; 33%), and half of the CBD carcinomas (50%) had strong TGF-alpha immunoreactivity. There was correlation between TGF-alpha and EGFR immunoreactivity in the tumour cases (r = 0.70, r2 = 0.49, P = 0.0001; simple regression analysis), although the rate of EGFR immunoreactivity in CBD and ampullary carcinomas was somewhat higher than that of TGF-alpha. However, no statistically significant correlation between TGF-alpha expression with patient survival or tumour recurrence (r = 0.11, r2 = 0.012, P = 0.65; simple regression analysis) was found.

CONCLUSIONS

Increased TGF-alpha expression occurs more frequently in gallbladder carcinoma than in gallbladder dysplasia, chronic cholecystitis, CBD or ampullary tumour, with no specific relationship to tumour grade, suggesting that TGF-alpha overexpression occurs early in the development of gallbladder cancers, and that biliary tract cancers have a different molecular origin. Correlation was found between TGF-alpha and EFGR expression in gallbladder and biliary tract tumours.

Correlation of cyclin D1 and Rb gene expression with apoptosis in invasive breast cancer

BACKGROUND

In vitro studies have shown that amplification and overexpression of the cyclin D1 gene can accelerate the progress of cells through the G1 phase. Therefore, cyclin D1 may have an apoptosis inhibiting effect. The retinoblastoma (Rb) gene was shown recently to be an important regulator of apoptosis.

AIMS

To evaluate whether expression of the cyclin D1 and Rb genes correlated with apoptotic counts in a group of 97 invasive breast cancers.

METHODS

Expression of the cyclin D1 and Rb genes was detected by standard immunnohistochemistry using paraffin wax embedded sections. Apoptotic cells were counted according to a strict protocol, in 10 fields of vision systematically spread over the most poorly differentiated area of the tumour, at a magnification of x630. Apoptotic cells counts were expressed as apoptotic cells/mm2.

RESULTS

Cyclin D1 overexpression was found in 49% of cases. Loss of Rb expression was found in 44% of cases, and occurred particularly in poorly differentiated tumours. Cyclin D1 and Rb expression showed a positive correlation (p = 0.003). Apoptotic counts varied from 1 to 62/mm2. There were no significant correlations between cyclin D1 overexpression and apoptotic counts in the total group or in the retinoblastoma protein (pRb) positive tumours. Loss of Rb expression also showed no correlation with apoptotic counts.

CONCLUSIONS

Cyclin D1 is frequently overexpressed in pRb positive tumours, but no evidence has been found for an anti-apoptotic effect of cyclin D1 overexpression or Rb expression in invasive breast cancer.

Expression of growth factors, growth-inhibiting factors, and their receptors in invasive breast cancer. II: Correlations with proliferation and angiogenesis

Growth factors may play an important role in tumour growth and angiogenesis by their influence on tumour cell proliferation or their effect on neovascularization. The aim of the present study was to determine which of the growth factors, growth-inhibiting factors, and their receptors investigated in a previous study are correlated with proliferation and angiogenesis in invasive breast cancer, with emphasis on the impact of possible autocrine and paracrine loops. Five growth factors and their receptors: platelet-derived growth factor A chain (PDGF-AA) and PDGF alpha receptor (PDGF alpha R), PDGF-BB and PDGF beta receptor (PDGF beta R), transforming growth factor alpha (TGF alpha) and its receptor epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) and its receptors (Flt-1 and Flk-1/KDR; two growth-inhibiting factors: transforming growth factor beta-1 (TGF beta 1) and TGF beta 2 and their receptor couple TGF beta R-I and TGF beta R-II; and basic fibroblast growth factor (bFGF) were stained in 45 cases of invasive breast cancer by standard immunohistochemistry on frozen sections. Staining in tumour cells, stromal cells, and endothelial cells was scored as negative or positive. Proliferation was determined by assessment of the mitotic activity index (MAI) and the degree of angiogenesis was measure by counting the number of microvessels (microvessel density: MVD) in the most vascularized area of the tumour. bFGF and EGFR showed positive correlations with the MAI, while TGF beta 2 showed a negative correlation. Expression of bFGF, TGF alpha, TGF beta 2, and EGFR correlated positively with the MVD. Co-expression of the TGF alpha/EGFR growth factor/receptor combination showed a stronger correlation with the MAI and the MVD than EGFR or TGF alpha alone, and the TGF beta 2/TGF beta R-I/TGE beta R-II combination showed a positive correlation with the MVD. In conclusion, the expression of several growth factors, growth factor receptors and growth-inhibiting factors showed correlations with the rate of proliferation and the degree of angiogenesis in invasive breast cancer. Some growth factor/receptor combinations showed stronger correlations with proliferation and angiogenesis than the growth factor or receptor alone, pointing to the importance of possible auto- and paracrine loops for stimulation of proliferation and angiogenesis by growth factors and their receptors.

Expression of growth factors, growth inhibiting factors, and their receptors in invasive breast cancer. I: An inventory in search of autocrine and paracrine loops

The aim of the present study was to investigate which growth factors, receptors, and growth inhibiting factors are expressed in invasive breast cancer. Five (angiogenic) growth factors and their receptors: platelet-derived growth factor A chain (PDGF-AA) and PDGF receptor alpha (PDGF alpha R), PDGF-BB and PDGF beta receptor, transforming growth factor alpha (TGF alpha) and its receptor epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) and its receptors vascular endothelial growth factor receptor I (Flt-1) and vascular endothelial growth factor receptor II (Flk-1/KDR); two growth inhibiting factors: transforming growth factor-beta-1 (TGF beta 1) and (TGF beta 2) and their receptor couple transforming growth factor beta receptor I (TGF beta R-I) and TGF beta R-II; and basic fibroblast growth factor (bFGF) were stained by standard immunohistochemistry on frozen sections in 45 cases of invasive carcinoma of the breast. Staining was scored as negative or positive in tumour epithelium, stroma, and blood vessels. TGF beta 1 and TGF beta 2 were expressed in the tumour cells in 67 per cent and 76 per cent of cases, respectively, whereas PDG beta R and TGF beta R-II were expressed in 0 per cent and 2 per cent, respectively. The other factors showed variable expression in tumour cells. All factors were expressed in the stroma in most cases, except Flt-1, Flk-1/KDR, TGF beta 2, and TGF beta R-II, which showed variable expression, and EGFR, which showed no expression. The endothelium was in most cases positive for bFGF, PDGF-AA, PDGF-BB, VEGF, PDGF alpha R, PDGF beta R, and TGF beta 1 but TGF beta/ was negative in most cases and TGF alpha, EGFR, Flt-1, Flk-1/KDR, TGF beta R-I, and TGF beta R-II were variably expressed. The most interesting possible auto/paracrine loops, as demonstrated on serial sections and by fluorescence double staining, were the TGF alpha/EGFR, TGF beta s/TGF beta R, VEGF/Flt-1, and the VEGF/Flk-1 combinations. In conclusion, growth factors, growth inhibiting factors, and their receptors are frequently expressed in invasive breast cancer. Indications for some possible auto- and paracrine loops have been found, which should encourage further study on the role of these factors in breast cancer proliferation and angiogenesis.

EGF-related peptides in the pathophysiology of the mammary gland

Normal mammary gland development is the result of complex interactions between a number of hormones and growth factors. Normal and malignant human mammary epithelial cells are able to synthesize and to respond to various different, locally acting growth factors and growth inhibitors. Among these, the EGF-related peptides play an important role in regulating the proliferation and differentiation of human mammary epithelial cells. EGF4 and TGF4 are able to stimulate the lobulo-alveolar development of the mammary gland in vivo as well they are involved in the pathogenesis of human breast cancer. Experimental evidence suggests that estrogen-induced proliferation of breast carcinoma cells is mediated in part by EGF-related growth factors. It has also been demonstrated that activation of certain cellular protooncogenes such as c-Ha-ras in human mammary epithelial cells results in cellular transformation and in an increased production of several EGF-related growth factors such as TGFalpha and amphiregulin. Coexpression of both EGF-related peptides and their own receptors frequently occurs in human breast carcinomas and in human breast cancer cell lines, suggesting that an autocrine pathway of uncontrolled cell growth sustains neoplastic transformation.

Steroid hormones and cancer: (III) observations from human subjects

Epidemiological evidence strongly suggests that steroid hormones are implicated in the risk of cancers of the breast, ovary and endometrium. However, it has proved difficult to implicate specific hormones or show that measurement of circulating hormones can identify women who will go on to develop malignant disease. There are, however, more convincing data that a proportion of established cancers are dependent upon steroid hormones for their continued growth and these underpin the use of endocrine manoeuvres in the treatment of these malignancies. Increased knowledge of the synthesis, release and mechanism of action of steroid hormones has led to the development of novel therapies for endocrine sensitive cancer and on-going research can reasonably be expected to identify tumour markers which can accurately predict hormone-dependency and provide better understanding of the mechanism by which response and resistance to therapy occur. The hope is that this knowledge will translate into more effective and rational endocrine treatment benefiting increased numbers of patients.

Expression of connective tissue growth factor mRNA in the fibrous stroma of mammary tumors

Desmoplasia, the formation of highly cellular, excessive connective tissue stroma associated with some cancers, shares many features with the wound healing response. Since connective tissue growth factor (CTGF) has previously been demonstrated to play a role in wound repair, we wanted to determine if it might be involved in the pathogenesis of stromal demoplasia in mammary cancer. We assayed 11 human invasive mammary ductal carcinomas by Northern blot and 7 out of 11 were positive for both CTGF expression and transforming growth factor-beta 1 (TGF-beta 1, a principal CTGF inducer). One specimen was positive only for TGF-beta 1. The remaining 3 tumors lacked significant stromal involvement and were negative for either factor. In every case we assayed, in which there was marked connective tissue involvement, both CTGF and TGF-beta 1 messages were found. We also assayed 3 murine mammary tumor models. The GI-101 xenograft model had marked stroma and was positive for both factors in-vivo, but positive for only TGF-beta 1 mRNA expression in culture where fibroblasts were absent. The DMBA murine tumor lacked significant stroma and was negative for CTGF and TGF-beta 1 expression by Northern blot, while the stromal rich DMBA-MMTV tumor contained multifocal desmoplasia and was positive for both factors. We performed in-situ hybridization for CTGF and TGF-beta 1 on the GI-101 and DMBA-MMTV tumors. CTGF message was observed only in the fibroblasts of the stroma, while TGF-beta 1 mRNA hybridization was present in tumor epithelial cells and leukocytes. These results suggest that cancer stroma formation involves induction of similar fibroproliferative growth factors (TGF-beta 1 and CTGF) as wound repair.

TGF-beta 1 mRNA expression in clinical breast cancer and its relationship to ER mRNA expression

Eighty nine primary breast cancers were investigated for the expression of TGF-beta 1 and ER mRNA using PCR of reverse transcribed RNA. PCR products were validated using Southern blots and hybridization with radiolabelled cDNA probes. TGF beta 1 mRNA was found to be expressed in 56/89 (63%) of the breast cancers while ER mRNA was expressed in 23/89 (26%) of the tumours. Using chi-square analysis TGF-beta mRNA expression was found to correlate significantly with ER mRNA expression (p < 0.001), in that virtually all tumours that expressed ER mRNA co-expressed TGF beta 1. In tumours that were ER mRNA negative, TGF beta 1 expression was more variable. These results suggest that during tumour progression, ER expression is lost more frequently than is growth factor expression.

Complex role of tumor cell transforming growth factor (TGF)-beta s on breast carcinoma progression

Growth inhibition by the TGF-beta s has been extensively studied in both normal and transformed mammary epithelial cells. It has been proposed that loss of autocrine TGF-beta mediated growth regulation is a critical event in breast tumorigenesis and several lines of in vitro and in vivo data support this hypothesis. However, a positive association between the expression of TGF-beta s by tumor cells and the progression or maintenance of breast cancinoma cells has been observed in many studies in in vivo tumor models. Possible mechanisms for these growth enhancing effects of TGF-beta include immunosuppression mediated by tumor TGF-beta s, enhanced angiogenesis, increased peritumoral stroma formation, and cell adhesion. The net effect of tumor cell TGF-beta on the biology of breast carcinogenesis would depend on the balance between autocrine growth inhibition of mammary epithelial cells and these growth enhancing effects.

Changes in expression of transforming growth factor beta mRNA isoforms in patients undergoing tamoxifen therapy

Tumour was obtained from 37 patients with oestrogen receptor-positive breast cancer, before and during treatment with tamoxifen, and examined qualitatively and semi-qualitatively for mRNA of the three mammalian TGF-beta isoforms. Levels of TGF-beta isoforms were then correlated with tumour response to tamoxifen, as assessed by monthly ultrasound. A high incidence of expression by each isoform was found in tumour material taken both before and during treatment. Semiquantitative assessment of mRNA showed that in the majority of tumours, expression of TGF-beta s did not change markedly with treatment, i.e. beyond that which might have been caused by method reproducibility and tumour heterogeneity (variations of < 100% between pre- and post-treatment samples). In those displaying significant variation with treatment, expression of TGF-beta 1 and -beta 3 increased or decreased in equal numbers, whereas TGF-beta 2 expression tended to increase with treatment. Subdividing tumours by clinical response revealed no significant association between changes in expression of TGF-beta 1 and TGF-beta 3. There was, however, a significant correlation between changes in expression of TGF-beta 2 and response (P = 0.018). Thus, of 15 responding tumours displaying substantial changes, 11 showed an increase in TGF-beta 2 expression with treatment, whereas none of the non-responding tumours were associated with increased expression. While not providing evidence for a generalised increase in TGF-beta expression with tamoxifen treatment, the present study suggests that response to tamoxifen therapy may be associated with an increase in expression of specific TGF-beta isoforms in some, but not all, tumours.

TGF-alpha immunoreactivity in laryngeal carcinoma: lack of prognostic value and correlation to EGF-receptor expression

BACKGROUND

Transforming growth factor alpha (TGF-alpha) is a polypeptide that is structurally similar to epidermal growth factor (EGF) that binds to the epidermal growth factor receptor (EGFR) and has been implicated in the development of several types of human tumours.

METHODS

The expression of TGF-alpha is examined in laryngeal squamous cell carcinoma (SCC) (n = 24) and non-neoplastic polyps (n = 7) using streptavidin-biotin immunohistochemistry and a monoclonal antibody to the TGF-alpha protein. These cases had been previously characterized for EGFR immunoreactivity. The carcinomas were classified as well differentiated (n = 2), moderately differentiated (n = 16) and poorly differentiated (n = 6). Tissues from metastatic tumour deposits in lymph nodes (n = 5) were also studied.

RESULTS

TGF-alpha overexpression was defined as intense immunoreactivity in more than two-thirds of tumour cells immunostained for TGF-alpha and was present in the majority of the SCC cases (n = 15; 63%) and metastatic tumour deposits (n = 4; 80%). In contrast, although some of the vocal cord polyps showed weak (n = 2) to moderate (n = 5) immunostaining, none had evidence of strong TGF-alpha immunoreactivity. The differences in TGF-alpha immunoreactivity were significant between primary laryngeal SCC and vocal cord polyps (P = 0.013; chi 2 test with continuity correction), and between metastatic laryngeal SCC and vocal cord polyps (P = 0.023; chi 2 test with continuity correction). There was no significant difference in TGF-alpha expression between the different grades of carcinomas (P = 0.92, chi 2 test) or between non-metastatic and metastatic carcinomas (P = 0.82; chi 2 test with continuity correction). No significant correlation was found between TGF-alpha expression and patient survival or tumour recurrence (r = 0.077, r2 = 0.006, P = 0.75; simple regression analysis), or between TGF-alpha expression and EGFR immunoreactivity (r = 0.325, r2 = 0.106, P = 0.0851).

CONCLUSIONS

In conclusion, increased TGF-alpha immunoreactivity is present in most cases of laryngeal SCC with no specific relationship to tumour grade, suggesting that it may be important in the development of laryngeal carcinomas but not in its progression. No significant correlation was found between TGF-alpha and EGFR expression in laryngeal tumours and TGF-alpha immunoreactivity is of no prognostic value.

Elevated plasma transforming growth factor-beta 1 levels in breast cancer patients decrease after surgical removal of the tumor

OBJECTIVE

The authors determined whether untreated breast cancer patients have elevated plasma levels of transforming growth factor-beta 1 (TGF-beta 1).

SUMMARY BACKGROUND DATA

Increased plasma TGF-beta 1 levels recently were found after chemotherapy in patients with advanced breast cancer. However, it currently is unknown whether this elevation in plasma TGF-beta 1 is caused by chemotherapy-induced normal tissue damage or whether it results from the presence of the tumor.

METHODS

An enzyme-linked immunosorbent assay was used to measure plasma TGF-beta 1 levels in 26 newly diagnosed breast cancer patients before and after definitive surgery. Patients were grouped by postoperative tumor status: 1) negative lymph nodes (group 1); 2) positive lymph nodes (group 2); and 3) overt residual disease (group 3). The site of TGF-beta 1 production in the tumors was localized by immunohistochemistry and in situ hybridization.

RESULTS

Plasma TGF-beta 1 levels were elevated preoperatively in 81% of the patients; TGF-beta 2 and TGF-beta 3 were undetectable. The preoperative TGF-beta 1 levels in the three patient groups were similar; however, the postoperative plasma TGF-beta 1 levels differed by disease status. The mean plasma TGF-beta 1 level in group 1 (n = 12) normalized after surgery (19.3 +/- 3.2 vs. 5.5 +/- 1.0 ng/mL, p < 0.001). In contrast, the mean plasma TGF-beta 1 levels remained above normal in both group 2 (n = 9) and group 3 (n = 5) after surgery. Transforming growth factor-beta 1 expression was found to be preferentially increased in the tumor stroma.

CONCLUSIONS

Breast tumors result in increased plasma TGF-beta 1 levels in 81% of patients. After surgical removal of the primary tumor, the plasma TGF-beta 1 level normalizes in the majority of patients; persistently elevated levels correlate with the presence of lymph node metastases or overt residual tumor. These findings suggest that the usefulness of TGF-beta 1 as a potential plasma marker for breast tumors deserves further study.

Transforming growth factor beta secretion from primary breast cancer fibroblasts

Transforming growth factor beta (TGF-beta) is a hormonally regulated growth inhibitor with autocrine and/or paracrine functions in human breast cancer. In vivo, enhanced immunohistochemical staining of extracellular TGF-beta 1 has been detected around stromal fibroblasts in response to the antiestrogen treatment. We have investigated the effects of tamoxifen on the production of TGF-beta by primary human breast fibroblast cultures in serum-free medium. Highly variable levels of mainly latent TGF-beta 1 were detected in conditioned media from both tumor and normal tissue derived fibroblasts. Hydroxy-tamoxifen was shown to increase latent TGF-beta 1 secretion in three of the eight tumor tissue-derived fibroblast cultures. Such effect of hydroxy-tamoxifen was not observed in fibroblast cultures established from normal adjacent breast tissue.

Expression of transforming growth factor alpha, amphiregulin and cripto-1 in human breast carcinomas

The expression of three epidermal growth factor (EGF)-related peptides, transforming growth factor alpha (TGF-alpha), amphiregulin (AR) and cripto-1 (CR-1), was examined by immunocytochemistry (ICC) in 68 primary infiltrating ductal (IDCs) and infiltrating lobular breast carcinomas (ILCs), and in 23 adjacent non-involved human mammary tissue samples. Within the 68 IDC and ILC specimens, 54 (79%) expressed immunoreactive TGF-alpha, 52 (77%) expressed AR and 56 (82%) expressed CR-1. Cytoplasmic staining was observed with all of the antibodies, and this staining could be eliminated by preabsorption of the antibodies with the appropriate peptide immunogen. Cytoplasmic staining with all of the antibodies was confined to the carcinoma cells, since no specific immunoreactivity could be detected in the surrounding stromal or endothelial cells. In addition to cytoplasmic reactivity, the AR antibody also exhibited nuclear staining in a number of the carcinoma specimens. No significant correlations were found between the percentage of carcinoma cells that were positive for TGF-alpha, AR or CR-1 and oestrogen receptor status, axillary lymph node involvement, histological grade, tumour size, proliferative index, loss of heterozygosity on chromosome 17p or overall patient survival. However, a highly significant inverse correlation was observed between the average percentage of carcinoma cells that expressed AR in individual tumours and the presence of a point-mutated p53 gene. Likewise, a significantly higher percentage of tumour cells in the ILC group expressed AR as compared with the average percentage of tumour cells that expressed AR in the IDC group. Of the 23 adjacent, non-involved breast tissue samples, CR-1 could be detected by ICC in only three (13%), while TGF-alpha was found in six (26%) and AR in ten (43%) of the non-involved breast tissues. These data demonstrate that breast carcinomas express multiple EGF-related peptides and show that the differential expression of CR-1 in malignant breast epithelial cells may serve as a potential tumour marker for breast cancer.

Epidermal growth factor-related peptides in the pathogenesis of human breast cancer

A number of different epidermal growth factor (EGF)-related peptides such as EGF, transforming growth factor alpha (TGF alpha), amphiregulin (AR), heregulin (HRG), and cripto-1 (CR-1), are coexpressed to varying degrees in both normal and malignant mammary epithelial cells. However, in general the frequency and level of expression of TGF alpha, AR, and CR-1 are higher in malignant breast epithelial cells than in normal mammary epithelium. In addition, several of these peptides such as TGF alpha and AR can function as autocrine and/or juxtacrine growth factors in mammary epithelial cells, and their expression is stringently regulated by mammotrophic hormones such as estrogens, activated proto-oncogenes that have been implicated in the pathogenesis of breast cancer, and other growth factors. The redundancy of expression that is observed for a number of these structurally related peptides in both normal and malignant mammary epithelial cells suggests that some of these peptides may be involved in regulating other aspects of cellular behavior such as differentiation in addition to proliferation.