Neu Oncoprotein Research Articles

An Expression of HER-2/neu Oncoprotein in Endometrial Cancer

An Expression of HER-2/neu Oncoprotein in Endometrial Cancer

Expression of HER-2/neu oncoprotein, DNA-ploidy and S-phase fraction in advanced ovarian cancer.

The immunohistochemical expression of HER-2/neu and cytofluorimetric data were retrospectively analyzed in a group of primary advanced ovarian cancers. Thirty-three out of 94 (35%) cases showed a specific p185/neu immunoreaction. No correlation between p185/neu expression and any of the clinico-pathologic parameters examined was observed. As far as cytofluorimetric data are concerned, 38 out of 69 (55%) of the tumors were diploid (DNA index = 1) while 31 (45%) were aneuploid (DNA index from 1.10 to 2.50 with a median value of 1.50). Ovarian tumors were defined as of low and high S-phase fraction in 68% and 32% of the cases, respectively. Tumor ploidy and S-phase fraction did not correlate with the clinico-pathologic characteristics or p185/neu oncoprotein expression. Aneuploid tumors had a higher S-phase fraction (mean: 15.81 +/- 13.44) than diploid tumors (mean: 8.89 +/- 7.98) (P < 0.01). p185/neu expression failed to affect significantly both overall and progression free survival. On the other hand tumor ploidy was found to be related to the prognosis of advanced ovarian cancer patients although the difference was not statistically significant. As far as progression free survival is concerned, the median time to recurrence was not reached for diploid cases whereas it was 21 months for aneuploid cases (P < 0.05). The 5-year survival for patients with a low S-phase fraction (58%) was significantly higher than for patients with high S-phase fraction tumors (28%) (P < 0.01). Median time to recurrence was 48 and 17 months for low and high S-phase fraction tumor patients, respectively (P < 0.05). However, in a multivariate analysis both tumor ploidy and S-phase fraction did not retain their prognostic value. The assessment of the role of the parameters examined in improving the prognostic characterization of ovarian cancer patients should be investigated in large multicenter clinical trials.

Expression of NEU/HER-2 oncoprotein (p185neu) in prostate tumors: an immunohistochemical study.

The expression of the neu oncogene product was investigated immunohistochemically in 36 cases of benign prostatic hyperplasia (BPH) and seven cases of adenocarcinoma of prostate (CaP). c-neu oncogene encodes a transmembrane growth factor receptor that has partial structural homology with EGF receptor, and is overexpressed and amplified in a number of human tumors, specially, breast cancers. Using a monoclonal antibody, AB-3, which recognizes -COOH-terminal of neu oncoprotein, we have analyzed immunohistochemically the expression of this protein in buffered formalin and Zamboni fluid-fixed surgically removed tissues. Focal patchy and/or diffused cytoplasmic staining of varying intensity was observed in 34 of 36 BPH cases. Four cases showed cell membrane staining as well (4/36 = 11%). All seven cases of adenocarcinomas had moderate to strong c-neu immunoreactivity, and two gave a distinct cell membrane-positive reaction (100%). The available data indicate that prostatic tumors as well as a high percentage of prostatic hyperplasia tissues express c-neu protein; however, its role in cellular proliferation needs further study.

Differential immunoreactivity of her-2/neu oncoprotein in prostatic tissues

To investigate HER-2/ neu oncoprotein immunoreactivity, monoclonal antibody TA1 immunohistochemical examination of flash-frozen radical prostatectomy specimens was performed ( n = 35). All prostatic specimens contained benign prostatic hyperplasia (BPH) and/or prostatic intraepithelial neoplasia (PIN), as well as prostatic carcinoma (CaP). HER-2/ neu oncoprotein immunoreactivity in BPH tissues was not significantly different than that for the PIN basal cell layer ( p = 0.10) or for the PIN luminal cells ( p = 0.17). There was significantly more HER-2/ neu oncoprotein immunoreactivity in BPH than in areas of CaP ( P < 0.001). There was no significant difference in the amount of immunoreactivity present in PIN basal cells when compared to the PIN luminal cells ( P = 0.49). Both the PIN basal cells and luminal cells stained for the HER-2/ neu oncoprotein to a higher degree than cells in the CaP areas ( P < 0.001 in both cases). HER-2/ neu oncoprotein immunoreactivity is present at a significantly higher degree in BPH and PIN than in malignant prostatic epithelium.

Prediction of Response to Adjuvant Chemotherapy in Premenopausal Lymph Node Positive Breast Cancer Patients with Morphometry, DNA Flow Cytometry and Her-2/Neu Oncoprotein Expression: Preliminary Results

The value of morphometry, DNA flow cytometry and HER-2/neu oncoprotein expression for prediction of response to adjuvant chemotherapy in premenopausal lymph node positive breast cancer patients was evaluated in a group of CMF treated patients and controls with long-term follow-up. In the treated group, the Morphometric Prognostic Index (cutpoint 1.1) was the best prognosticator (p less than 0.0001, MC = 16.9), followed by the Mitotic Activity Index, the volume percentage epithelium and the number of positive nodes. For the controls, only the % HER-2/neu oncoprotein expression revealed significant differences (p less than 0.0001, MC = 16.3). When directly comparing treated patients and controls stratified for a certain parameter, no significant differences were obtained, although a trend towards improved survival in the treated group was present for some of the subgroups for several parameters. These preliminary results indicate that morphometric features and quantitative HER-2/neu oncoprotein expression may be important factors for identifying cases that will or will not respond to adjuvant chemotherapy.

Study of the biological and prognostic significance of the antigen CaMBr8 on breast carcinoma.

We previously reported that the expression on the primary tumour of the antigen CaMBr8 was related to a short survival, attributable either to higher tumour aggressiveness or a poor response to oophorectomy. To further verify the CaMBr8 prognostic value, we analysed retrospectively 862 breast cancer patients with a 19 year follow-up. In this series, CaMBr8 expression was found to be associated to some negative prognostic factors (premenopausal status, lymphnode invasion, a high number of mitosis and HER-2/neu oncoprotein expression), but had no influence on the patients' survival. Direct association with a poor prognosis was only evident in patients with lobular or mixed breast carcinoma, which however represent only a small fraction of the total breast cancers. Another possibility was that CaMBr8 could identify a subgroup of patients which did not respond to hormone therapy. To verify this hypothesis we evaluated on a second series of 116 patients the relationship between CaMBr8 expression and hormone-receptor levels. A negative association emerged which was also observed in vitro in the human breast cancer line MCF-7 treated with Sodium Butyrate, a differentiation inducer, which reduced hormone-receptor levels and increased CaMBr8 expression. In conclusion, the longer survival of CaMBr8 negative tumour patients observed in the initial study, was probably related to a better response to oophorectomy, due to the hormone-receptor level of their tumours.

乳癌ｔ１症例における定量細胞化学的検討 核ＤＮＡ量，ＰＣＮＡ／ｃｙｃｌｉｎおよびＨＥＲ‐２／ｎｅｕ蛋白を用いた解析

乳癌ｔ１症例における定量細胞化学的検討 核ＤＮＡ量，ＰＣＮＡ／ｃｙｃｌｉｎおよびＨＥＲ‐２／ｎｅｕ蛋白を用いた解析

Expression of c-erb B-2/neu proto-oncogene in human prostatic cancer tissues and cell lines.

Both amplification and overexpression of c-erb B-2/neu have been associated with the progression and possible prognosis of a number of human cancers. In this study, we demonstrated that c-erb B-2/neu may also play an important role in human prostate cancer. Our conclusion is based on the following observations: (1) A monoclonal antibody raised against a peptide sequence from the C-terminal domain of the human c-erb B-2/neu gene product reacted positively with 68.7% (11 of 16) of the human prostatic cancer tissue extracts analyzed by western blot procedure. These results were supported by the immunohistochemical staining of the prostatic cancer specimens; 80% (12 of 15) showed positive staining, primarily around the plasma membranes of the prostatic cancer cells. c-erb B-2/neu oncoprotein was not detectable in normal prostate tissues (five examined by immunohistochemical staining and three by western blotting) or in human benign prostatic hyperplasia (two examined by immunohistochemical staining and six by western blotting) and was expressed less abundantly with lower intensity in "normal" human prostate tissues adjacent to cancerous prostate tissue (5 of 12 examined by immunohistochemical staining). We observed no evidence of c-erb B-2/neu gene amplification in 10 fresh human prostatic cancer specimens examined by Southern blotting and in the cultured human prostatic cancer cell lines PC-3, DU-145, and LNCaP. (2) The c-erb B-2/neu protein was detected in both androgen-receptor-positive (LNCaP) and -negative (PC-3 and DU-145) human prostate cancer cell lines. Positive immunostaining of c-erb B-2/neu protein was found to be associated predominantly with the plasma membranes of PC-3 cells, but was also found to be widespread in the cytoplasmic region of the LNCaP cells and in the perinuclear region of the DU-145 cells. (3) Like prostate-specific antigen (PSA) expression, c-erb B-2/neu mRNA expression was also positively regulated by androgen in androgen-receptor-positive LNCaP cells in vitro and LNCaP tumors in vivo. When LNCaP tumors were grown in castrated male hosts, levels of c-erb B-2/neu and PSA mRNA expression decreased initially, but rebounded at 3 wk to levels comparable to those expressed by tumors maintained in intact adult male hosts.

Monoclonal 3c6f9 distribution in human breast carcinomas: image cytometry of immunocytochemical assays

MoAbF9 immunoreactivity was investigated in frozen sections of 123 breast carcinomas using an avidin or streptavidin biotin peroxidase kit. A standardized computer image analysis system was used to evaluate immunostaining. The percent of cell surface staining and mean optical densities were correlated with morphological criteria of prognosis such as tumor size histological grade, blood and lymph invasion and axillary lymph node involvement, with immunoreactivity to other MoAb, i.e. Ki67, anti-RE and anti-RP, anti-p.HER-2/neu and with tumor aneuploidy and AgNORs content in tumor cell nuclei. Despite some heterogeneity, MoAbF9 was reactive with all breast carcinomas tested. The percent of F9 immunostained cell surface and mean optical density increased with Ki67 immunoreactivity, tumor aneuploidy and AgNORs nucleus surface but were independent of p.HER-2/neu oncoprotein distribution and tumor receptor content. These findings suggest that F9 could not only allow detection axillary lymph node micrometastases but also be used as plasmatic marker for tumor recurrence and metastases.

Prognostic significance of her‐2/neu expression in breast cancer and its relationship to other prognostic factors

Archival surgical specimens from 1,210 female breast cancer patients treated between 1968 and 1971 and with a 19-year follow-up were reanalyzed with special reference to several parameters, such as size of the primary tumor, axillary nodal involvement, histologic grade, degree of inflammatory infiltrate (LPI) of the tumor and expression of the neu oncoprotein (p185) as detected by immunohistochemistry. In a multifactorial analysis the 4 former factors were found to be independent prognostic parameters. Over-expression of p185 was found to be related to tumor size and grade and to LPI but not to pathologic nodal status. Over-expression of p185 showed a negative impact upon survival in node-positive but not in node-negative patients. However, in the subset of node-negative patients without LPI, p185 over-expression showed the same correlation with a poor prognosis as in node-positive patients. In contrast, in node-negative and LPI-positive patients, p185 over-expression correlated with a good prognosis. Also, the prognosis of patients with positive nodes, presence of LPI and no p185 over-expression was similar to that of patients with negative nodes, absence of LPI and p185 over-expression.

Structural analysis of the transmembrane domain of the epidermal growth factor receptor.

The ligand-binding domain of the epidermal growth factor (EGF) receptor is separated from the cytoplasmic protein tyrosine kinase domain by a predicted single transmembrane segment. Antipeptide antibodies prepared against the outer portion of the predicted transmembrane segment confirmed this area was exposed only when cells were treated with permeabilizing agents. To investigate structural requirements for signal transduction by the transmembrane domain, three types of mutant EGF receptor were prepared. The first type was designed to shorten the transmembrane domain, the second to place proline substitutions within this domain, and the third to make amino acid substitutions analogous to those present in the transforming c-erbB2/neu oncoprotein. Mutant human receptors were expressed in null recipient mouse B82L and Chinese hamster ovary cells. All receptors bound EGF and exhibited EGF-stimulated protein tyrosine kinase activity in vivo as assayed using a 125I-labeled monoclonal anti-phosphotyrosine antibody. EGF stimulated growth of cells expressing each mutant receptor with similar dose-response characteristics. In contrast to other growth factor receptors, the transmembrane domain of the EGF receptor is tolerant to a variety of changes which neither mimic EGF action by constitutive activation nor interfere with ligand-induced signal transduction.

Constitutively activated neu oncoprotein tyrosine kinase interferes with growth factor‐induced signals for gene activation

The neu receptor oncoprotein tyrosine kinase, capable of transforming cultured fibroblasts and causing mammary carcinomas in transgenic mice, carries a point mutation in its transmembrane domain and shows a constitutive tyrosine kinase activity. We analyzed the neu tyrosine kinase and its substrates in transfected NIH 3T3 fibroblasts by phosphotyrosine immunoblotting. Tyrosine phosphorylated proteins were similar but not identical in epidermal growth factor (EGF)-stimulated cells expressing the human EGF receptor (EGFR) or a chimeric EGFR/neu receptor but differed from phosphotyrosyl proteins constitutively expressed in neu oncogene-transformed cells. The neu oncoprotein in the latter cells was phosphorylated in tyrosine in a ligand-independent manner and had a shortened half-life in comparison with the normal neu protein. Tumor promoter pretreatment inhibited ligand-induced receptor tyrosine phosphorylation and decreased tyrosine phosphorylated neu oncoprotein. Prolonged pretreatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) also prevented the induction of immediate early growth factor-regulated genes in response to neu activation. Expression of the neu oncogene but not the protooncogene in NIH 3T3 cells was associated with enhanced levels of the jun and fos oncoproteins and loss of serum growth factor induction of immediate early mRNA responses. The constitutively activated neu oncoprotein tyrosine kinase thus deregulates cellular genomic responses to growth factors.