Staining For TGF-alpha Research Articles

Concomitant and isolated expression of TGF-alpha and EGF-R in human hepatoma cells supports the hypothesis of autocrine, paracrine, and endocrine growth of human hepatoma.

Single and double immunohistochemical staining for transforming growth factor (TGF)-alpha and epidermal growth factor-receptor (EGF-R) was done in order to identify the localization of TGF-alpha and EGF-R in human hepatocellular carcinoma (HCC). Single immunohistochemical staining for TGF-alpha showed immunoreactivity in the cytoplasm of hepatoma cells in 22 of 30 cases of HCC. The localization of TGF-alpha was heterogeneous from HCC cells to HCC cells. In the surrounding regenerative nodules, the hepatocytes were mildly to moderately positive for TGF-alpha. The proliferating bile ductules and peripheral nerves were also immunopositive for TGF-alpha. Single immunohistochemical staining for EGF-R demonstrated a linear localization of EGF-R along the cell membrane of the HCC cells in 21 of the 30 cases of HCC. In the regenerative nodules, the hepatocytes also showed linear staining along the cell membrane. Double staining for TGF-alpha and EGF-R in 12 cases of HCC showed a concurrent localization of TGF-alpha and EGF-R in some hepatoma cells and isolated localization of the two substances of other HCC cells. These combinations either abruptly moved around or intermingled with each other. These immunohistochemical results thus support the theory of an autocrine, paracrine, and endocrine mechanism of TGF-alpha and EGF-R on the proliferation of human hepatocellular carcinoma.

Elevation of transforming growth factor-alpha mRNA and protein expression by diverse tumor promoters in SENCAR mouse epidermis.

The study presented here was designed to further investigate the role of transforming growth factor-alpha (TGF alpha) in skin tumor promotion by examining the ability of 12-O-tetradecanoylphorbol-13-acetate (TPA) and several non-phorbol ester promoters to alter TGF alpha mRNA and protein levels in mouse epidermis. Total RNA was isolated from SENCAR mouse epidermis at various times after single topical treatments with TPA (3.4 nmol), chrysarobin (220 nmol), okadaic acid (2.5 nmol), and thapsigargin (8.5 nmol). Northern analyses of these isolated RNA samples revealed that all four tumor promoters transiently elevated TGF alpha mRNA levels. Whereas TPA, okadaic acid, and thapsigarin elevated TGF alpha mRNA levels over similar time courses (peak at 4-8 h), chrysarobin elevated TGF alpha mRNA levels with a markedly delayed time course (peak at 24-48 h). More detailed studies with TPA also revealed that multiple treatments (four over a 2-wk period) transiently elevated TGF alpha mRNA in both the epidermis and the dermis. The time courses for changes in TGF alpha mRNA after multiple TPA treatments were similar for both tissues. To facilitate studies of altered TGF alpha mRNA expression in mouse epidermis and possibly other mouse tissues, a semiquantitative reverse transcriptase-polymerase chain reaction method was developed. This method faithfully revealed changes in TGF alpha mRNA levels with all four tumor-promoting agents similar to those determined by northern blot analyses. Immunofluorescence analysis of frozen sections from promoter-treated skin revealed elevated TGF alpha protein levels in both epidermis and dermis, although staining was most intense in the epidermal layer. Immunofluorescence analysis of epidermal hyperplasia adjacent to a full-thickness wound also demonstrated significant epidermal TGF alpha staining. Collectively, these results indicate that mechanistically diverse tumor promoter stimuli elevate TGF alpha mRNA and protein in SENCAR mouse epidermis. Elevated levels of TGF alpha may play an essential role in mitogenic stimulation during tumor promotion by diverse promoting stimuli.

Prolactin induced expression of interleukin‐1 alpha, tumor necrosis factor‐alpha, and transforming growth factor‐alpha in cultured astrocytes

Prolactin (PRL) is a potent mitogen in cultured astrocytes. Because one of the major effects of astrocyte proliferation is the expression of inflammatory cytokines, we examined the effect of PRL-induced mitogenesis on the expression of interleukin-1 (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-alpha (TGF-alpha) in cultured astrocytes. Astrocytes were stimulated with PRL or growth hormone (GH), and the expression of cytokines was determined by immunohistochemistry and Western blot analysis. Following incubation of astrocytes with 1 nM PRL for 6 h, strong positive staining of IL-1 alpha and TNF-alpha, but not TGF-alpha, was found. No detectable staining for the above cytokines was found in vehicle, or GH treated astrocytes. When astrocytes were incubated in the presence of 1 nM PRL for 18 h, strong positive staining for IL-1 alpha and TGF-alpha was found. Immunocytochemical analysis of the expression of TNF-alpha and IL-1 alpha in PRL stimulated astrocytes suggested that the expression of IL-1 alpha preceded the expression of TNF-alpha. To confirm this observation, Western blot analyses were performed on extracts from astrocytes incubated with 1 nM PRL in unstimulated astrocytes, IL-1 alpha levels were not detectable. In astrocytes stimulated with 1 nM PRL, expression of IL-1 alpha was clearly detected after 1 h of incubation, and IL-1 alpha levels continued to increase during the course of the experiment (6 h). In contrast, in astrocytes stimulated with 1 nM PRL, an increase in the expression of TNF-alpha was first apparent after 2 h of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of transforming growth factor alpha (TGFA) and its precursors with malignant change in Barrett's epithelium: Biological and clinical variables

Adenocarcinomas of the gastro-esophageal junction (GEJ) and those arising in Barrett's esophagus (BE) are increasing in the West and have a poorer prognosis than distal stomach cancers. This has been attributed mainly to anatomical location, but biological factors such as growth-regulatory molecules have been implicated. We have investigated the expression of one of these factors, TGF alpha, and its precursor prepro TGF alpha in 82 adenocarcinomas of GEJ (32 resected specimens and 50 biopsies) as well as in 48 BE biopsies without tumor, by immunohistochemistry and by Western-blot analysis. TGF alpha staining was shown in the cytoplasm and membrane of cells. Western blot confirmed that most immunoreactivity was against mature TGF alpha (5.6 kDa), but higher-molecular-weight bands were also identifiable, suggesting some reactivity with prepro protein. TGF alpha expression was more extense and intense in intestinal metaplasia and cancer. The tubular histological type of adenocarcinoma was more often positive than the signet-ring type. Primary tumors with lymph-node metastases also had increased TGF alpha expression. We conclude, therefore, that there is differential regulation of the expression of TGF alpha and its precursors during esophageal tumorigenesis.

Expression of p53, transforming growth factor alpha, epidermal growth factor receptor, and c- erbB-2 in endometrial carcinoma and correlation with survival and known predictors of survival

Abnormal expression of p53, transforming growth factor alpha (TGF alpha), epidermal growth factor receptor (EGFR), and c- erbB-2 occurs in a variety of cancers and in some cases is associated with poor prognosis. Immunoperoxidase staining using these markers in formalin-fixed, paraffin-embedded endometrial carcinoma tissue was performed to determine whether immunoreactivity correlates with survival and known prognostic variables. Cases included 84 endometrioid adenocarcinomas, five adenoacanthomas, 12 adenosquamous carcinomas, 11 serous carcinomas, 15 clear cell carcinomas, and one carcinosarcoma for a total of 128 cases. Frequencies of immunoreactivity were as follows: p53, 37 of 128 (29%); TGF alpha, strong (2+) 23 of 128 (18%) and intermediate (1+) 26 of 128 (20%); EGFR, strong (3+) 21 of 128 (16%) and intermediate (2+ or 1+) 83 of 128 (65%); and c- erbB-2, strong (2+) four of 128 (2%) and intermediate (1+) three of 128 (1%). p53 and TGF alpha staining showed statistically significant correlations with decreased length of survival ( P < .0017 and P < .0013, respectively, generalized Savage [Mantel Cox]). p53 immunoreactivity correlated with tumor types, grade, and stage. Transforming growth factor alpha staining correlated with increased depth of invasion and presence of vascular invasion. Epidermal growth factor receptor staining did not correlate with length of survival or known prognostic variables. c- erbB-2 staining correlated with tumor type. In the multivariate analysis p53 and TGF alpha staining were not independent predictors of survival when other variables were taken into account, including grade, stage, tumor type, presence of vascular invasion, and depth of invasion. Grade and stage were the only independent predictors of survival when used in combination in a Cox proportional hazards model.

Epidermal growth factor, transforming growth factor-alpha, and epidermal growth factor receptor localization in the baboon (Papio anubis) uterus during the menstrual cycle and early pregnancy.

Marked alterations occur in the synthesis of endometrium-specific proteins during the first third of pregnancy in the baboon. Because epidermal growth factor (EGF) expression has been associated with proliferation in the human and mouse endometrium, we hypothesized that EGF, transforming growth factor-alpha (TGF alpha), and EGF receptor (EGF-R) expression in baboon endometrium may be modulated by the early invasive trophoblast and play a role in decidualization of the endometrial stroma. Endometrial tissue was obtained from cycling baboons (n = 4-5 per time point), ovariectomized steroid-treated baboons (n = 4 per group), or from pregnant baboons on days 18-60 of pregnancy (n = 2-4 per group). The tissue was fixed in Bouin's solution and embedded in paraffin for immunocytochemistry using polyclonal antibodies against EGF and EGF-R and a monoclonal antibody to TGF alpha. Endometrial staining was located almost entirely in the glandular epithelium for TGF alpha and EGF-R in the follicular phase animals, whereas EGF staining was strongest in the periglandular stroma. In the luteal phase, specific staining for EGF also was detected in the glands as well as the periglandular stroma. There appeared to be little difference in endometrial staining between the late follicular and mid-luteal phase for TGF alpha and EGF-R. A similar pattern was observed in the steroid-treated animals. In the endometrium from pregnant animals, EGF, TGF alpha, and EGF-R intensely stained the glandular epithelium on days 18, 25, and 32. Both EGF and EGF-R showed light stromal staining on days 18 and 25. Light stromal TGF alpha staining was present on day 25 and became moderately intense by day 32. By day 60, the most intense staining for EGF and EGF-R was stromal. Staining of TGF alpha continued to be strong in the remaining epithelium through day 60. In placenta, EGF and EGF-R intensely stained the syncytiotrophoblast, but not the cytotrophoblast, whereas TGF alpha stained only the villous cytotrophoblast and intermediate cytotrophoblast within maternal blood vessels. There appeared to be no change in this staining pattern or intensity in the placenta throughout early pregnancy. This study demonstrates the presence of EGF, TGF alpha, and EGF-R in the endometrium during the cycle and early pregnancy. The detection of EGF, TGF alpha, and EGF-R in the stromal cells during pregnancy correlated with the onset of decidualization. We propose that EGF, TGF alpha, and EGF-R may play a role in glandular development during the cycle and in decidualization and implantation during early pregnancy.

Retinal and preretinal localisation of epidermal growth factor, transforming growth factor alpha, and their receptor in proliferative diabetic retinopathy.

A number of growth factors have been implicated in the development and perpetuation of preretinal fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). The aim of this study was to determine the potential role of epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and their receptor (EGF-R) in PDR development. Immunostaining for EGF, TGF-alpha, and EGF-R was compared between normal retina, PDR retina, and PDR preretinal membranes. Weak staining for EGF and EGF-R was observed throughout the neural retina from non-diabetic eyes while weak to moderate staining for TGF-alpha was observed in the ganglion cell layer and the inner and outer nuclear layers. In contrast, intense staining for EGF and TGF-alpha and moderate staining for EGF-R were observed throughout the PDR retina. Immunoreactivity for EGF, TGF-alpha, and EGF-R was seen in the majority of the 11 excised membranes studied and, though variable, was generally greater than that observed in normal retinas. These results suggest an autocrine/paracrine role for EGF, TGF-alpha, and EGF-R in PDR.

IMMUNOHISTOCHEMICAL DETECTION OF CRIPTO-1, AMPHIREGULIN AND TRANSFORMING GROWTH-FACTOR-ALPHA IN HUMAN GASTRIC CARCINOMAS AND INTESTINAL METAPLASIAS

The expression and localization of cripto-1 (CR-1), amphiregulin (AR) and transforming growth factor alpha (TGFalpha) were assessed by immunocytochemistry in 37 primary human gastric tumors, 30 noninvolved gastric mucosa samples that were adjacent to carcinoma but exhibited intestinal metaplasia and 37 adjacent, noninvolved gastric mucosa samples. Seventeen (46%), nineteen (51%) and twenty-one (57%) carcinomas showed staining for CR-1, AR and TGFalpha, respectively; whereas sixteen (53%), eight (26%) and five (17%) intestinal metaplasias were reactive with the anti-CR-1, anti-AR and anti-TGFalpha antibodies, respectively. In contrast, none of the normal, noninvolved gastric mucosa samples reacted with the TGFalpha antibody and only 1 (3%) of these samples showed weak staining with the anti-CR-1 antibody. However, 8 (21%) of the normal gastric mucosa samples showed moderate levels of staining with the AR antibody. Within the carcinomas, there was a slight trend for association between TGFalpha and CR-1 expression (p<0.05), but no correlation was found between epidermal growth factor receptor and CR-1 expression. Staining for p53 was observed in 26 (70%) of the carcinomas, 3 (10%) intestinal metaplasias and none of the gastric mucosa samples. This data demonstrate that CR-1, like TGFalpha, may be a tumor marker for a subset of gastric carcinomas in addition to being an important factor in the early stages of gastric cancer development.

EGF and TGF-α in the human kidney: Identification of octopal cells in the collecting duct

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha) are well-known mitogens expressed in the kidney. Their human renal cell origin has not been conclusively identified. The distribution of EGF and TGF-alpha was investigated immunohistochemically in the adult human kidney in comparison with the monkey and rodent kidney. In humans, as in the monkey, two variants of EGF immunoreactivity were detected. One was present along the apical cell surfaces and diffusely in the cytoplasm of the thick ascending limb (TAL), co-localizing with Tamm-Horsfall protein, and in the distal convoluted tubule (DCT). The other occurred as overall membranous staining in the connecting tubule and cortical collecting duct (CD), and mainly as basal staining in the rest of the CD. The EGF stained cells in the cortical and outer medullary CD reached a diameter of 40 mu and were identified as intercalated or dark cells; they displayed a peculiar octopus-like shape, bearing long lateral extensions that stretched underneath and between 20 surrounding smaller negative cells. Cytoplasmic TGF-alpha staining appeared in the DCT and decreased further on. (1) the normal human distal nephron displayed EGF and TGF-alpha immunoreactivity in a partly complementary segmental and subcellular distribution pattern, partly differing from that in rodents. (2) EGF immunostaining revealed the presence of long lateral projections on CD intercalated cells; this peculiar morphology suggests a modulatory role within the CD epithelium, possibly involving the EGF immunoreactivity on their surface.

Interaction of transforming growth factor-alpha and epidermal growth factor receptor in breast carcinoma. An immunohistologic study

Interaction of transforming growth factor-alpha (TGF-alpha) with its receptor, epidermal growth factor receptor (EGFR), has been implicated as an autoregulatory autocrine mechanism of breast epithelial proliferation. To examine the interrelationship and clinical relevance of TGF-alpha and EGFR in breast carcinoma, methanol-fixed cryostat sections from 73 patients were immunostained with monoclonal antibodies to epidermal growth factor (EGF), EGFR, and TGF-alpha. Neither EGFR nor TGF-alpha staining was diagnostic or specific for the detection of malignant neoplastic cells. Both exhibited staining along the basal lamina of most benign ducts and lobules. TGF-alpha staining was observed in neoplastic cells in 41% and in non-neoplastic cells (peritumoral stroma and benign duct/lobular epithelium) in 36% of patients. Staining for EGF and TGF-alpha failed to correlate with node status or grade; however, TGF-alpha negative tumors were more frequently positive for estrogen receptor (ER) (70% versus 14%; P = 0.03). The presence of EGFR correlated with positive lymph node status (P = 0.004), poor differentiation (P = 0.001), and negative ER status (P = 0.0001). EGFR staining was more common in neoplasms which recurred, but this approached significance only in the group with node-negative disease (mean follow-up, 52 months; P = 0.06), and neoplastic cell TGF-alpha correlated with disease recurrence in patients with node-positive disease (no recurrence, -13% positive versus recurrence, -52% positive; P = 0.01). Concurrent TGF-alpha/EGFR staining, present in 18% of tumors, also was predictive of disease recurrence (no recurrence, 3% positive for both versus recurrence, 31% positive for both, P = 0.03). TGF-alpha is heterogeneously expressed in neoplastic and host-derived components of breast tumors. Concurrent EGFR/TGF-alpha immunostaining may characterize a clinically aggressive subset of breast carcinomas, possibly reflecting autocrine interaction, and conferring growth advantage or metastatic phenotype.

Immunocytochemical localization of transforming growth factor-alpha and epidermal growth factor receptor in human fallopian tubes and cumulus cells.

Transforming growth factor-alpha (TGF-alpha) has been shown to be a potent stimulant of oocyte maturation and embryonic development. The role of maternal growth factors and their mechanism of action in early mammalian development is not well understood. In this study, the presence of TGF-alpha and epidermal growth factor receptor (EGF-R) in human cumulus cells and fallopian tubes was investigated by immunocytochemical techniques. The fallopian tube showed intense staining for TGF-alpha in the apical region of the epithelial cells, and the cumulus cells showed intense staining for EGF-R on cell membranes. The presence of TGF-alpha in the fallopian tube epithelium and its receptor on cumulus cells suggest a paracrine mechanism between maternal growth factors and the developing embryo.

Transforming growth factor-alpha and its receptor are expressed in the epithelium of the rat prostate gland.

Transforming growth factor-alpha (TGF alpha) is a growth regulatory polypeptide factor that is expressed by several prostatic tumor cell lines. In this investigation, we examined whether TGF alpha is expressed during morphogenesis of the rat prostate gland. We first examined whether the prostate gland expressed TGF alpha by immunohistochemistry. Using a sheep antiserum directed against the mature sequence of TGF alpha, immunoreactivity was identified in the ventral and lateral, but not the dorsal, lobes of the prostate gland from 9-week-old rats. TGF alpha immunoreactivity was localized to a supranuclear site of the epithelial cells, with no immunoreactivity in the stromal cells or elsewhere in the prostate gland. A mouse monoclonal antibody directed against a TGF alpha epitope near cysteine-16 also identified the polypeptide. Furthermore, we confirmed that TGF alpha was synthesized in the epithelial cells of the ventral prostate gland, using an antiserum raised against the intracellular sequences of the transmembrane precursor. To assess the primary target for TGF alpha, we examined expression of receptors for TGF alpha (epidermal growth factor receptor) and found receptors to be localized to the apical surface of the epithelial cells of the ventral prostate gland. We next investigated a potential developmental role for TGF alpha in the rat prostate by examining TGF alpha expression in ventral rat prostate glands ranging from 8 days postpartum to 9 weeks of age. We found that TGF alpha expression was directly proportional to the developmental stage of the gland. Significantly, the fourth week of prostate development marked the appearance of TGF alpha expression in the supranuclear region of the epithelial cells. Immunohistochemical staining of progressively mature prostates of 5 and 6 weeks that contain more complex acinar formations exhibited more intense and highly localized TGF alpha staining. In conclusion, TGF alpha and its receptor have been identified in the apical region of epithelial cells of the rat prostate, and there is reason to believe that TGF alpha may function as an autocrine factor that promotes differentiated functions in the prostate gland.

Transforming growth factor-alpha and its receptor are expressed in the epithelium of the rat prostate gland

Transforming growth factor-alpha (TGF alpha) is a growth regulatory polypeptide factor that is expressed by several prostatic tumor cell lines. In this investigation, we examined whether TGF alpha is expressed during morphogenesis of the rat prostate gland. We first examined whether the prostate gland expressed TGF alpha by immunohistochemistry. Using a sheep antiserum directed against the mature sequence of TGF alpha, immunoreactivity was identified in the ventral and lateral, but not the dorsal, lobes of the prostate gland from 9-week-old rats. TGF alpha immunoreactivity was localized to a supranuclear site of the epithelial cells, with no immunoreactivity in the stromal cells or elsewhere in the prostate gland. A mouse monoclonal antibody directed against a TGF alpha epitope near cysteine-16 also identified the polypeptide. Furthermore, we confirmed that TGF alpha was synthesized in the epithelial cells of the ventral prostate gland, using an antiserum raised against the intracellular sequences of the transmembrane precursor. To assess the primary target for TGF alpha, we examined expression of receptors for TGF alpha (epidermal growth factor receptor) and found receptors to be localized to the apical surface of the epithelial cells of the ventral prostate gland. We next investigated a potential developmental role for TGF alpha in the rat prostate by examining TGF alpha expression in ventral rat prostate glands ranging from 8 days postpartum to 9 weeks of age. We found that TGF alpha expression was directly proportional to the developmental stage of the gland. Significantly, the fourth week of prostate development marked the appearance of TGF alpha expression in the supranuclear region of the epithelial cells. Immunohistochemical staining of progressively mature prostates of 5 and 6 weeks that contain more complex acinar formations exhibited more intense and highly localized TGF alpha staining. In conclusion, TGF alpha and its receptor have been identified in the apical region of epithelial cells of the rat prostate, and there is reason to believe that TGF alpha may function as an autocrine factor that promotes differentiated functions in the prostate gland.

Autocrine growth mechanisms of cholesteatoma epithelium

Transforming growth factor alpha (TGF alpha) and interleukin 1 alpha (IL-1 alpha) are known to be produced by normal human keratinocytes stimulating their proliferation. The distribution and expression of TGF alpha and IL-1 alpha were examined in specimens of middle ear cholesteatoma by means of immunohistochemical methods using a monoclonal antibody against TGF alpha and a polyclonal one against IL-1 alpha. Normal retroauricular skin was stained for comparison. Staining for TGF alpha was consistently stronger in cholesteatoma epithelium than in normal epidermis, and encompassed all epithelial cell layers. Immune cells occurring in the stroma of cholesteatoma also reacted positively for TGF alpha. The intensity of staining for IL-1 alpha was markedly stronger in cholesteatoma tissue than in normal epidermis. All cellular layers of the squamous epithelium of cholesteatoma stained strongly and uniformly for IL-1 alpha, whereas the keratin layer was negative for IL-1 alpha. In the connective tissue beneath the cholesteatoma epithelium intensely positive cells were scattered between negative stromal cells. These data are consistent with autocrine stimulation of the squamous epithelium of cholesteatoma by TGF alpha and IL-1 alpha as well as with a paracrine stimulation by immune cells. Both factors contribute to the unrestrained growth of cholesteatoma in the middle ear cavity.

Immunohistochemical localization of transforming growth factor-alpha in human endometrium, decidua, and trophoblast.

Transforming growth factor-alpha (TGF-alpha) was localized immunohistochemically in human proliferative and secretory endometrium, decidua, and trophoblast from first, second, and third trimester pregnancies. In proliferative endometrium, TGF-alpha immunostaining was moderate to intense and localized predominantly to stromal cells, whereas glandular staining was absent to light. After ovulation, TGF-alpha staining was light within the stroma, but moderate to intense around spiral arterioles. Moderate to intense staining was also detected in glandular and surface epithelium in secretory endometrium, with no staining noted in subnuclear vacuoles. In hypersecretory endometrium, staining was predominantly epithelial. In decidua, TGF-alpha was detected in intermediate trophoblast and on the surface epithelium. In first trimester trophoblast, TGF-alpha was detected in both cytotrophoblast (CT) and syncytiotrophoblast. Cytoplasmic staining was light in CT and moderate to intense in ST, with particular staining of plasma membranes. Intense TGF-alpha staining of nuclear membranes in CT was noted. TGF-alpha staining was light to absent in second and absent in third trimester trophoblast. This study demonstrates immunoreactive TGF-alpha in tissues known to be responsive to epidermal growth factor, and also demonstrates the presence of immunoreactive TGF-alpha associated with nuclear membranes. Thus, TGF-alpha may play an autocrine/paracrine role in endometrial development and trophoblast function.

Transforming growth factor-alpha: identification in bovine corpus luteum by immunohistochemistry and northern blot analysis

Transforming growth factor-alpha (TGF-alpha), a product of the thecal cells, has potent mitogenic and steroidogenic influences on cells within the ovarian follicle. Whether TGF-alpha continues to be produced in those follicles that go on to ovulate and form a corpus luteum is currently under investigation. In the present study, TGF-alpha was localized in the bovine corpus luteum by means of immunoperoxidase staining using a monoclonal antibody for TGF-alpha that does not cross-react with epidermal growth factor. In corpora lutea from the mid-luteal phase of the cycle TGF-alpha staining was found predominantly in the large luteal cells. Northern blot analysis using a human TGF-alpha cDNA probe hybridized to the 4.5-4.8 kb TGF-alpha transcript in RNA from the corpus luteum. These studies provide new evidence that TGF-alpha, a potent paracrine regulator within the ovarian follicle, continues to be expressed in the corpus luteum.

Increased expression of transforming growth factor alpha after transfection of a human hepatoblastoma cell line with the hepatitis B virus.

The expression of transforming growth factor alpha (TGF-alpha) was examined in a human hepatoblastoma cell line, Hep G2, which does not contain hepatitis B virus (HBV) DNA, and in the cell line 2.2.15, which was formed by the transfection of Hep G2 cells with the complete HBV DNA, to study the possibility that HBV and TGF-alpha could function as co-factors in hepatocarcinogenesis. Northern blot hybridization of RNA extracted from these cell lines, with densitometric analysis, revealed expression of the TGF-alpha gene in the transfected cells at a level three times higher than in the nontransfected cells. Staining of the cells using a monoclonal antibody to TGF-alpha and the avidin-biotin-peroxidase immunohistochemical method revealed a much higher intensity of TGF-alpha staining in the transfected cell line. These findings show that the presence of HBV DNA appears to cause a significant up-regulation of the TGF-alpha gene. This effect on the TGF-alpha gene may be a mechanism by which HBV contributes to the etiology of hepatocellular carcinoma in some patients.

Transforming growth factor-α expression in benign and malignant human prostatic disease

Investigation of biological variables in prostatic disease may not only prevent patients with a good prognosis being overtreated, but allow better selection of appropriate therapy, and may identify potential targets for novel therapies. This study investigates the growth factor transforming growth factor-alpha (TGF alpha) expression in benign and malignant prostatic biopsies using both radioimmunoassay and immunohistochemistry, considering its role in malignant epithelial transformation and as a prognostic indicator. Biochemical methods were less satisfactory than the more selective immunohistochemical methods, due to the heterogeneity of prostatic tissue. Seventy-one percent of benign biopsies (range 0-18.62ng/mg DNA) and 69% of malignant biopsies (range 0-11.1ng/mg DNA) had detectable levels of TGF alpha using radioimmunoassay. Immunohistochemical staining for TGF alpha identified expression in 15% of benign (4 out of 27) and 53% malignant biopsies (18 out of 34). Positive staining was also identified in premalignant lesions and within stromal elements, thus implying the factor's role in autocrine/paracrine growth and/or malignant transformation. Immunostaining for TGF alpha may enhance detection of premalignant lesions and small foci of malignant glands which are otherwise difficult to identify using standard histopathological techniques.

In situ distribution of transforming growth factor α in normal human tissues and in malignant tumours of the ovary

The distribution of transforming growth factor alpha (TGF-alpha) in human normal tissues from the uterus, Fallopian tube, ovary, small and large intestine, lung, spleen, kidney, and skin was studied by immunohistochemistry. TGF-alpha was found in epidermis, bronchial epithelium, intestinal mucosa, renal tubules, endo- as well as in exocervical and endometrial epithelium, and in the serous epithelium of the Fallopian tube. No TGF-alpha was detected in the stromal components of any of the tissues nor in any of the pre- and post-menopausal ovaries studied. Twenty-nine ovarian tumours including 23 ovarian carcinomas, one malignant mixed Mullerian tumour, two ovarian metastases of gastrointestinal carcinomas, one dysgerminoma, one sarcoma, and one fibroma were studied for TGF-alpha by the same immunohistochemical method. In 25 cases, specific cytoplasmic staining for TGF-alpha of epithelial tumour cells could be demonstrated. The pattern and intensity of the TGF-alpha immunostain varied among the TGF-alpha-positive tumours. No TGF-alpha was found by immunohistochemistry in the remaining four cases nor in the stromal tumour components of any of the lesions studied. Northern blot analysis for TGF-alpha mRNA was performed on 12 of the tumours. While the immunohistochemistry and blotting results correlated well in ten cases, discordant results were obtained in two lesions.

Transforming growth factor-alpha in the adult bovine ovary: identification in growing ovarian follicles.

The pituitary gonadotropins and gonadal steroids are required for normal follicular growth and development but neither has been shown to act directly as a granulosa cell mitogen in vitro. A number of polypeptide growth factors, however, are known to have pronounced mitogenic effects on the cells of the follicle. We have localized transforming growth factor-alpha (TGF-alpha), a potent mitogen, in bovine thecal cells via immunoperoxidase staining using a monoclonal antibody for TGF-alpha that does not cross-react with epidermal growth factor. TGF-alpha staining is most intense in the theca of follicles at the discrete physiological stages known to show rapid granulosa cell growth (small follicles of 0.7-2.0 mm diameter). Staining intensity for TGF-alpha declines in large preovulatory follicles, coincident with the known decline in granulosa cell mitosis. These studies provide further evidence for paracrine interactions in the ovary and show that TGF-alpha may play an important role in the regulation of follicular development in the adult bovine ovary.