Amplification and over-expression of c-erbB-2 in transitional cell carcinoma of the urinary bladder

Espressione di oncogeni di proliferazione e morte cellulare nel carcinoma superficiale della vescica: Expression of oncogenes in relation to cell proliferation and death in superficial bladder carcinoma

Although superficial bladder cancer may be considered “benign”, it is still today a many-sided neoplasm with a prognosis that cannot be well-defined with known traditional parameters. Proliferation indices Ki67 and AgNOR associated with the expression of some oncogenes (p53, Rb, c-myc, BCL2, c-erbB-2) in relation to traditional parameters could help in the prognosis definition of individual patients. 111 patients with superficial bladder cancer were studied for this purpose, relating the grade, stage, follow-up and morphotype to the proliferation indices. Significant correlations were found with AgNOR, but only for grade with Ki67. The study of the oncoproteins and their different expression showed that those alterations typical of infiltration are already present in the superficial forms, with a significant correlation between oncogenic alterations and grade and stage of disease (p53, Rb) on the one hand, and above all of disease-free interval and progression (c-erbB-2) on the other. Lastly, assessment of the oncoproteins c-myc and BCL2, oncogenes connected with the programmed cell death mechanism (apoptosis), showed important correlations with the neoplastic progression of disease in relation to the p53 expression and proliferative activity.

c-erbB-2 overexpression in the dysplasia/carcinoma sequence of Barrett's oesophagus

AIMS--To investigate overexpression of the oncoprotein c-erbB-2 in the dysplasia/carcinoma sequence of Barrett's columnar-lined oesophagus (CLO). METHODS--Immunohistochemical staining was performed using the monoclonal antibody NCL-CB-11 on formalin fixed tissue from 31 cases of Barrett's carcinoma, 20 cases of cancer associated dysplastic CLO, seven cases of dysplastic CLO without cancer, and 20 cases of non-dysplastic CLO. Membranous staining was regarded as positive for c-erbB-2 overexpression; cytoplasmic staining was recorded separately as its significance is uncertain. RESULTS--Membranous c-erbB-2 overexpression was observed in eight of 31 (26%) carcinomas and in none of the cases of dysplastic CLO. Variable cytoplasmic staining was seen in four of 31 (13%) tumours and seven of 27 (26%) cases of dysplastic CLO. No staining was observed in non-dysplastic CLO. CONCLUSIONS--C-erbB-2 overexpression is a relatively late event in the development of some Barrett's carcinomas and is unlikely to be involved in the early stages of neoplastic transformation of CLO.

Growth factors in bladder cancer

This article is an overview of peptide growth factors, their receptors, and signal-transduction pathways that play a role in bladder cancer. Included in this overview are epidermal growth factor receptor and its ligands, erbB2, fibroblast growth factors, insulin-like growth factor, the transferrin receptor, and transforming growth factor-beta. The use of growth factors or growth factor receptors for diagnostic and therapeutic interventions is also discussed.

Cytoplasmic c-erbB-2 protein expression correlates with survival in Dukes' B colorectal carcinoma

The prognostic significance of c-erbB-2 expression was studied in paraffin wax embedded colorectal cancer tissue using a monoclonal antibody. One hundred and sixty-four patients with Dukes' B disease were studied. Membranous staining was not detected in any case. Cytoplasmic c-erbB-2 staining was seen in 55 cancers (33.5%). Cytoplasmic staining was unrelated to patient age (P = 0.31), sex (P = 0.69), tumour site (P = 0.69), size (P = 0.57), histological grade (P = 0.42) or ploidy status (P = 0.21) but was found more frequently in obstructing cancers (P = 0.03). Mean follow up of the patient population was 6.3 years. Five-year-survival estimated by the Kaplan-Meier life-table method was 47% for those with cytoplasmic c-erbB-2 staining and 77% for those without (log rank analysis; P < or = 0.0001). Stepwise regression analysis identified c-erbB-2 staining (relative risk, 2.51; P = 0.0005) and bowel obstruction (relative risk, 1.99; P = 0.015) as independent predictors of survival. It is suggested that cytoplasmic c-erbB-2 expression may provide a useful marker of tumour behaviour in Dukes' B colorectal cancer.

neu is not involved in N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide-induced bladder carcinoma or 2-amino-4-(5-nitro-2-furyl)thiazole transformation of rat bladder epithelial cells

Enhanced c-erbB-2/neu expression has been linked with a poor prognosis in human bladder cancer. Previous reports have shown that a point mutation at nucleotide T2012 in the coding region of the transmembrane domain of the rat gene is sufficient to confer transformation potential on this gene. We examined the comparative levels of p185neu as well as the sequence around the hotspot (T2012) of the neu gene of rat bladder cells transformed by 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) or established in culture from N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT)-induced rat bladder tumors. We concluded that increased p185neu expression did not correlate significantly with tumorigenicity. No alterations in nucleotide sequences of the neu gene were observed in either in vitro model.

C-erbB-2 immunostaining: problems with interpretation

AIMS

To assess the consistency and reproducibility of assessment of c-erbB-2 immunostaining, and to examine some of the problems relating to inter- and intraobserver variability in the documentation of positive staining; to profile the spectrum of cytoplasmic and membranous staining in a wide range of tumour types.

METHODS

A total of 283 neoplasms were examined for immunohistochemical expression of the c-erbB-2 oncoprotein. Three independent observers were required to assess intensity both of membrane and cytoplasmic staining on a three point and then a four point scale. Extent of positive staining was also assessed on a two point scale. A minimum of two weeks elapsed between assessments using the differing scales.

RESULTS

Positive membrane staining was documented by one or more observers in 16.6% of tumours examined. This positivity was largely restricted to bladder, renal, and breast tumours. The overall level of disagreement as to the presence or absence of membranous staining was 11.3%. Cytoplasmic staining was identified in 55.5% of tumours studied. The level of disagreement as to the presence or absence of cytoplasmic staining was 26.5%.

CONCLUSIONS

Intraobserver variability was minimal, indicating that each pathologist was adhering to internal reproducible standards. Interobserver variability was greater, indicating that the interpretation of c-erbB-2 immunostaining may require set guidelines. It is suggested that assessment should be referenced to a standard positive control, that a three tier system for grading of intensity and a two tier system for grading of extent should be adopted, and that the evaluation should be agreed by at least two pathologists. The presence of cytoplasmic staining should continue to be routinely recorded until its biological role and clinical implications are fully understood.

Neu is not involved in N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide- induced bladder carcinoma or 2-amino-4-(5-nitro-2-furyl)thiazole transformation of rat bladder epithelial cells

Enhanced c-erbB-2/neu expression has been linked with a poor prognosis in human bladder cancer. Previous reports have shown that a point mutation at nucleotide T2012 in the coding region of the transmembrane domain of the rat gene is sufficient to confer transformation potential on this gene. We examined the comparative levels of p185neu as well as the sequence around the hotspot (T2012) of the neu gene of rat bladder cells transformed by 2-amino-4-(5-nitro-2-furyl)thiazole (ANFT) or established in culture from N-[-4-(-5-nitro-2-furyl)-2- thiazolyl]formamide (FANFT)-induced rat bladder tumors. We concluded that increased p185neu expression did not correlate significantly with tumorigenicity. No alterations in nucleotide sequences of the neu gene were observed in either in vitro model.

Expression of epidermal growth factor receptor in bladder cancer as related to established prognostic factors, oncoprotein (c-erbB-2, p53) expression and long-term prognosis

The expression of epidermal growth factor receptor (EGFR) was studied immunohistochemically in 234 cases of transitional cell bladder cancer. EGFR was overexpressed in 35% of cases and distinct nuclear localisation of EGFR positivity was found in 31% of the tumours. Overexpression was related to invasive growth, grade 2-3 histology, non-papillary type, DNA aneuploidy and high proliferation rate of cancer cells. The expressions of p53 and EGFR were interrelated, while expression of c-erbB-2 was independent of EGFR expression. Progression of superficial tumours, recurrence-free survival and survival were independently related to overexpression of EGFR in multivariate analysis. T category, S-phase fraction and non-papillary type included all the available prognostic information when the entire cohort was analysed by multivariate methods. The results show that overexpression of EGFR is related to several malignant features and prognosis in superficial bladder cancer. Moreover, the results suggest that overexpression of EGFR is usually a late event in bladder cancer development related to genetic instability rather than an early event in malignant transformation. Further studies are still needed to establish whether the direct measurement of cell proliferation or analysis of growth factor receptors and other oncoproteins gives more accurate prognostic information in bladder cancer.

Clear cell carcinoma arising in a pleomorphic adenoma of the submandibular gland

Clear cell carcinoma of salivary gland is a rare neoplasm. We report a third case of clear cell carcinoma arising in a pleomorphic adenoma and also in an extraparotid location. We document the immunohistochemical profile of the tumour including reactivity with a marker for the c-erbB-2 oncoprotein and suggest a myoepithelial origin for these lesions. The presence of a tetraploid stemline may account for the rapid tumour progression in this case.

Image analysis in quantitative PCR. An application for the measurement of c-erbB-2 oncogene amplification in DNA from human tumours

We present an application of image analysis for the direct quantification of PCR products after gel electrophoresis and ethidium bromide staining of DNA. This procedure has been applied to the development of an assay based on competitive PCR for the measurement of the degree of amplification of c-erbB-2 oncogene in DNA from human tumours. In this method two DNA species (genomic and competitor) compete for PCR amplification. Since results are calculated from the final competitor/genomic ratio any variable affecting the rate of PCR amplification has no effect on the accuracy of the ratio measurement. Results are reported which show that even large variations in the experimental conditions (number of PCR cycles, sample volumes and extracted DNA quality) did not interfere with the precision of the measurement of the competitor/genomic ratio.

Mutations of the p53 gene in carcinomas of the urinary system

Deletion of p53, which is an anti-oncogene located on chromosome 17p, was reported to be present at a high incidence in tumor cells of colorectal carcinoma, as well as osteosarcoma of the familial cancer syndrome. Mutations of the p53 gene were investigated in 59 surgical specimens of primary carcinomas of the urinary system from 57 patients, using the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis. The PCR products were sequenced using the dideoxy chain termination method or the DNA sequencer. The tumors examined were 20 transitional cell carcinomas (TCC) and 39 renal cell carcinomas (RCC). Mutations of the p53 gene were detected in 20.0% (4/20) of TCC and were present in 16.7% (1/6) of the tumors invading the muscular layer. In two patients with simultaneous double bladder TCC, the mutations were found only in the larger tumors. In RCC, mutations were detected in 7.7% (3/39) of patients. No significant correlation between the presence of the mutation and the clinicopathologic parameters was found in RCC except that the three tumors with p53 gene mutations were clear cell carcinomas. These results suggest that p53 gene mutations play a possible role in both carcinogenesis and progression of TCC, but the p53 gene mutations may not be significant in development of RCC.

Clinical significance of DNA ploidy and S-phase fraction and their relation to p53 protein, c-erbB-2 protein and HCG in operable muscle-invasive bladder cancer

DNA ploidy and S-phase fraction (SPF), determined by flow cytometry were studied in 118 patients with muscle-invasive transitional cell carcinoma (TCC) of the urinary bladder, scheduled for cystectomy after pre-operative radiotherapy (20 Gy/1 week) with or without systemic cisplatin-based neo-adjuvant chemotherapy. The correlation between these parameters and immunohistochemically demonstrated p53, c-erbB-2 and HCG was also investigated. There were 16 DNA diploid and 102 DNA non-diploid tumours. DNA ploidy was not related to the T (all 118 patients) or pN (58 patients) category, occurrence of stage reduction or cancer-related 5 years survival. Patients with high SPF tumours tended, however, to have a better prognosis than those with low SPF TCC reaching the level of significance (P < 0.05) for those patients who had high SPF tumours and received neo-adjuvant chemotherapy. Fifty-one of the tumours were p53 positive. p53 positive tumours were significantly more often found in TCC with low SPFs than in those with high SPFs. Respectively 12 and 9% of the tumours were HCG and c-erbB-2 positive, without correlation to DNA ploidy or SPF. We conclude that DNA ploidy does not represent a prognostic parameter in muscle-invasive operable bladder carcinomas. A high SPF, determined by FCM, may be helpful to identify patients with chemotherapy-sensitive TCC of the urinary bladder.

p53 and erbB-2 protein overexpression are associated with early invasion and metastasis in bladder cancer

Overexpression of p53 and erbB-2 was studied by immunohistochemistry in formalin-fixed tissue samples of 179 patients with transitional cell carcinoma of the urinary bladder. p53 immunostaining was strongly correlated with tumour stage (P < 0.0001). This was driven by a marked difference in p53 expression between pTa (37% positive) and pT1 (71%) tumours, while there was no difference between pT1 and pT2-4 tumours. Similarly, a strong overall association between p53 expression and grade (P < 0.0001) was driven by a marked difference between grade 1 (28%) and grade 2 tumours (71%), and there was no significant difference between grade 2 and grade 3 tumours. Surprisingly, the frequency of erbB-2 overexpression was higher in pT1 tumours (74%) than in either pTa (49%; P = 0.0265) or pT2-T4 (56%; P = 0.0645) tumours. Both p53 and erbB-2 expression was also associated with metastasis. Metastases were found in 77% of patients with p53 positive primary tumours, but in only 50% of the patients with p53 negative primary tumours (P = 0.022). Metastases were found in 66% of patients with erbB-2 positive primaries, but in only 37% of the erbB-2 negative primaries (P = 0.020). Of 32 patients with positivity for both p53 and erbB-2, 84% developed metastases, as compared to 49% of patients with positivity for either one or neither positive (P = 0.002). We conclude that both p53 and erbB-2 overexpression are associated with early invasion in bladder cancer. Furthermore, p53 and erbB-2 may be important predictors for metastasis.

C-erbB-2 oncoprotein immunostaining in serous effusions

The product of c-erbB-2 gene is detected in a proportion of carcinomas from various sites and is generally associated with a high degree of malignancy. A series of 58 effusions containing malignant cells and 16 cytologically negative serous effusions was assessed by immunocytochemical methods for c-erbB-2 expression using the monoclonal antibody NCL-B11, which recognizes the internal domain of the c-erbB-2 oncoprotein. Both alcohol-fixed smears and cell blocks from formalin-fixed specimens were used. A crisp, clear cut membrane-associated positive staining was evident in 51% (30/58) malignant effusions and was restricted to metastatic adenocarcinomas. Breast and ovarian cancers showed the highest incidence of positivity. Mesotheliomas as well as non-neoplastic effusions were consistently negative. Paraffin blocks from formalin-fixed cells displayed a weak immunoreactivity when compared with their alcohol-fixed counterparts. The study shows that the c-erbB-2 oncoprotein can be easily identified in standard cytological smears: it can be of assistance in differentiating adenocarcinomas from mesotheliomas, and in selected cases it can provide a further prognostic indicator, replacing tissue immunohistochemistry.

Gene amplification detected in carcinoma cells from human urinary bladder washings by the polymerase chain reaction method

BACKGROUND

Urinary bladder carcinoma often is diagnosed from malignant cells in bladder washings obtained at cystoscopic examination. In some cases, there are difficulties distinguishing between cytologic Grades 1 and 2. Detection of genetic alterations in combination with morphologic analysis may facilitate the diagnosis.

METHODS

The presence of amplified c-erb-B2 and epidermal growth factor receptor (EGF-R) was examined in tumor cells present in bladder washings. The gene copy number was determined with the polymerase chain reaction (PCR).

RESULTS

The authors detected amplified c-erb-B2 and EGF-R in cancer cells of cytologic Grade 2 and 3 tumors. They did not detect amplification in cytologic Grade 1 tumor cells or in cells from bladders, without known malignant neoplasms.

CONCLUSIONS

Examination of genetic alterations, in combination with morphologic analysis, facilitates the diagnosis of carcinoma.

Expression of c-erbB-2 protein, neuron-specific enolase and DNA flow cytometry in locally advanced transitional cell carcinoma of the urinary bladder

Expression of c-erbB-2 protein, neuron-specific enolase (NSE) and DNA ploidy was studied by immunohistochemistry and flow cytometry in formalin-fixed and paraffin-embedded specimens from 104 patients with locally advanced transitional cell carcinoma of the bladder. Positive membrane bound c-erbB-2 staining was found in 15% of the tumours, and 38% of the tumours were positive for NSE. Only one tumour stained positively for both NSE and c-erbB-2. Expression of c-erbB-2 protein and NSE was neither correlated to tumour stage nor to histopathological grade. The frequency of non-diploid tumours was 78% in 49 c-erbB-2/NSE negative tumours, 98% in 40 NSE positive tumours, and 100% in 16 c-erbB-2 positive tumours (P = 0.004). Whether the c-erbB-2 expression is a useful prognostic marker in addition to other conventional parameters, remains to be shown.

Reduced expression of TGF beta is associated with advanced disease in transitional cell carcinoma

The gene structure and expression of the related peptide regulatory factors TGF beta 1 and TGF beta 2 were studied in a panel of seven urothelial carcinoma cell lines and 40 transitional cell carcinomas. The latter comprised 15 grade 1, 18 grade 2 and 5 grade 3 tumours and two cases of carcinoma in situ. Control tissues included ten matched 'field' biopsies and 17 other biopsies including 11 biopsies of macroscopically normal urothelium, two of which were from patients with no history of bladder cancer. No amplification of rearrangements of either TGF beta 1 or TGF beta 2 were detected in any sample. A complex pattern of expression or the two genes was found in the urothelial cell lines. High, but variable levels of the 2.5 kb TGF beta 1 transcript were detected and lower and more variable levels of the three (4.1 kb, 5.1 kb and 6.5 kb) transcripts of TGF beta 2 were detected. Although those cell lines expressing most TGF beta 1 tended to express less TGF beta 2 transcript there was no clear-cut relationship. In comparison, no TGF beta 2 transcript was identified in any primary transitional cell carcinoma or control tissue. Markedly reduced or undetectable levels of TGF beta 1 transcript were detected in 4/15 (26%) grade 1, 5/18 (28%) grade 2 and 3/5 (60%) grade 3 tumours. There was no clear relationship to tumour stage, lymphocytic infiltration or stromal content of the tumours. Clinical review one year after the 2 year period of tumour collection showed that 6/9 (66%) of patients with tumours with reduced levels of transcript had died or had disease which was not controllable by local resection and 3/9 (33%) had developed tumour re-occurrences. In comparison, in the group with normal levels of expression of TGF beta 1, 3/18 (17%) had disease which was not controllable by local means, 9/18 (50%) had tumour re-occurrence and 6/18 (33%) had no evidence of disease. The association of reduced expression of TGF beta 1 and advanced disease was statistically significant P < 0.02 (Fisher's test). Although the sample size is small, we suggest that the loss of expression of TGF beta 1 may be a potential marker of progressive disease or prognosis in transitional cell carcinoma and warrants further study.

Construction of immunoradiometric assay for circulating c-erbB-2 protooncogene product in advanced breast cancer patients

The human c-erbB-2 protooncogene product (erbB-2 protein) is a 185 kilodalton glycoprotein closely related to epidermal growth factor receptor protein. In this study, we measured the concentration of circulating erbB-2 protein in cancer patients by means of a new immunoradiometric assay (IRMA). Two monoclonal antibodies (MoAbs), SV2-61 gamma and 6G10, recognize erbB-2 protein but bind to separate epitopes. SV2-61 gamma was used as an immunoadsorbent and 6G10 as an 125I-labeled probe. A serum was considered positive for erbB-2 protein if the percent binding exceeded the mean of the normal group by more than 3 standard deviations. Eleven of 21 patients with advanced breast cancer and 1 of 15 with advanced gastric cancer were positive. Serum erbB-2 protein levels correlated well with the therapy and the status of the patients with breast cancer. On the contrary, all patients with advanced colon, ovarian, or pancreatic cancers, showed levels below the cut-off value. These results suggest that circulating erbB-2 protein can be measured using the newly constructed IRMA. Since c-erbB-2 protooncogene amplification and overexpression are accepted as a good marker of aggressiveness, relapsing potency, and poor prognosis, this IRMA should be a promising tool with which to help manage breast cancer patients.

An immunohistochemical study of c-erbB-2 protein in gastric carcinomas and lymph-node metastases: is the c-erbB-2 protein really a prognostic indicator?

An immunohistochemical study of the c-erbB-2 protein was conducted on formalin-fixed paraffin-embedded tissue sections from 136 primary gastric carcinomas and 50 metastatic lymph-node tumors obtained at gastrectomy. Expression of the protein was detected in 35 of 136 primary gastric carcinomas (25.7%) and 22 of 50 metastatic lymph nodes (44%). The staining pattern of tumor cells was classified as membranous or cytoplasmic. An immunohistochemical study using serially diluted antibody demonstrated that 82.6% of positive cases in metastatic lymph nodes showed c-erbB-2 immunoreactivity stronger than that in the primary tumors. Membranous staining was stronger than cytoplasmic staining. c-erbB-2 protein of the cytoplasmic as well as membranous types was confirmed to be a 185-kDa whole molecule by immunoblotting. Correlation between the expression of c-erbB-2 protein and clinical and histological parameters was investigated. No significant correlation between 5-year survival rate of patients and expression of c-erbB-2 protein was found. In the poorly differentiated carcinoma group possessing c-erbB-2 protein, overall survival was significantly shorter than in cases without protein expression (p < 0.01). We conclude that c-erbB-2 protein is not a useful prognostic indicator in gastric carcinomas.

Immunocytochemical localization of c-erbB-2 protein in transitional cell carcinoma of the urinary bladder

The level of expression and cellular localization of the c-erbB-2 gene product in transitional cell carcinoma of the urinary tract is controversial. Analysis of the c-erbB-2 gene structure and comparison of its expression in the same cells by Southern, Northern and immunoblotting, and by immunocytochemistry minimize the errors of interpretation inherent in one technique. Such a 'correlative study' has been performed on tumours from 82 patients. c-erbB-2 gene amplification was detected in 14 per cent of initial tumours and was associated with grade (P < 0.001). Raised levels of mRNA were seen in those tumours with increased gene copy number and in 13 per cent of the remainder. Immunoblotting detected the expected 185 kD immunoreactive protein and a 155 kD protein associated with high gene copy number. Immunocytochemistry localized c-erbB-2 immunoreactivity to the cell membrane and cytoplasm, and the latter predominated. Four antibodies to c-erbB-2 (AB-3, 21N, pAb 1, and NCL CB11) were compared on contiguous sections of the same tumour and showed the same pattern of immunoreactivity. Similarly, analyses carried out in three independent laboratories identified the same cellular localization. Membrane and cytoplasmic immunoreactivity was demonstrated in all tumours with gene amplification or increased mRNA levels and in 40 per cent of the remaining tumours. We showed that immunocytochemistry requires careful standardization of techniques and quantitation between different groups. However, despite variations in the intensity of immunoreactivity, the total number of positive cells remained constant. Therefore quantitation must be based on the number of positive cells and, ideally, their immunoreactive content relative to normal and positive tissue controls.

An immunohistologic evaluation of C-erbB-2 gene product in patients with urinary bladder carcinoma

BACKGROUND

Amplification or overexpression of the c-erbB-2 gene have been reported to correlate with poor patient prognosis in human breast, gastric, and ovarian cancer. Recently, the c-erbB-2 gene product was found to be expressed frequently in the urinary bladder carcinoma. In the current study, the presence of the c-erbB-2 gene product in urinary bladder carcinomas was compared with patient outcome to evaluate whether c-erbB-2 gene product could identify a subset of patients who are destined to have a poor prognosis.

METHODS

Immunohistologic study of the c-erbB-2 gene product was done in formaldehyde-fixed paraffin-embedded tissue specimens obtained from 88 transitional cell carcinomas of the human urinary bladder. Eighty-three patients who underwent complete tumor resection by total cystoprostatectomy (30 patients) or by bladder-preserving operations such as transurethral surgery (50 patients) or partial cystectomy (3 patients) entered a follow-up study. The other five patients did not enter the follow-up study because of lost follow-up (2 patients) or distant metastasis at the time of surgery.

RESULTS

The c-erbB-2 gene product was expressed in 23 of 88 patients (26%), showing an increase in the expression rate corresponding to the advancement of tumor grade (P < 0.05) and tumor stage (P < 0.2). The 5-year disease-free survival rate was 48.5% for patients with c-erbB-2 negative tumors versus 9.7% for those with c-erbB-2 positive tumors (P < 0.01). The 5-year actuarial survival rate was 65.5% for patients with c-erbB-2 negative tumors versus 41.8% for those with c-erbB-2 positive tumors (P < 0.05). Multivariate analysis using Cox regression model showed that the c-erbB-2 gene product tissue status was a significant prognostic factor independent of grade and stage of the tumor.

CONCLUSIONS

The results suggest that the c-erbB-2 gene product could be a tumor marker to identify a malignant subgroup in bladder carcinomas.

Rare expression of the c-erbB-2 oncoprotein in salivary gland tumors: an immunohistochemical study

An immunohistochemical study of c-erbB-2 oncoprotein expression was carried out on 201 cases of primary salivary gland tumors, using a polyclonal antibody, raised to the intracytoplasmic domain of the c-erbB-2 oncogene product. An intense membrane reactivity was observed in one case of sialocarcinoma transformed from pleomorphic adenoma (n = 8) and one case of mucoepidermoid carcinoma (n = 22). A comparative histopathologic evaluation of c-erbB-2 positive tumors showed marked variation in cell size, nuclear pleomorphism, multinucleation, a high mitotic rate and increased lymphoid cell infiltration and an aggressive clinical course with poor survival. The results indicate that c-erbB-2 oncoprotein is rarely expressed in malignant salivary gland tumors. However, the overexpression appears to have a distinct histopathologic feature, but a larger study incorporating histopathology and clinical data would be necessary to correlate the significance of c-erbB-2 oncogene product in salivary malignant tumors.

Expression of c-erbB-2 protein in papillary thyroid carcinomas

c-erbB-2 protein expression was investigated immunohistochemically in frozen thyroid tissue specimens from 42 patients using a polyclonal sheep antibody. c-erbB-2 immunoreactivity was detected in 12 out of 17 papillary carcinomas, while no c-erbB-2 protein immunostaining was seen in cases of follicular adenoma (five cases), follicular carcinoma (five cases) or medullary carcinoma (one case), nor in cases of non-neoplastic tissue, including normal thyroid tissue from tumour-bearing glands. RNA was extracted from 51 thyroid tissue samples from 34 of the above patients, and c-erbB-2 mRNA was analysed by slot-blot hybridisation. c-erbB-2 mRNA was detectable in all samples, but papillary carcinomas and lymph node metastases showed significantly higher levels of c-erbB-2 mRNA compared to non-neoplastic tissue. The present demonstration of positive c-erbB-2 immunostaining in papillary thyroid carcinomas is contradictory to previous findings on formalin-fixed, paraffin-embedded material, and emphasises the importance of tissue quality for c-erbB-2 protein detection.