Immunohistochemical demonstration of c-erbB-2 oncoprotein in gastric adenocarcinoma: comparison of cryostat and paraffin wax sections and effect of fixation

Deciphering the Hazardous Effects of AFB1 and T-2 Toxins: Unveiling Toxicity and Oxidative Stress Mechanisms in PK15 Cells and Mouse Kidneys

In China, animal feeds are frequently contaminated with a range of mycotoxins, with Aflatoxin B1 (AFB1) and T-2 toxin (T-2) being two highly toxic mycotoxins. This study investigates the combined nephrotoxicity of AFB1 and T-2 on PK15 cells and murine renal tissues and their related oxidative stress mechanisms. PK15 cells were treated with the respective toxin concentrations for 24 h, and oxidative stress-related indicators were assessed. The results showed that the combination of AFB1 and T-2 led to more severe cellular damage and oxidative stress compared to exposure to the individual toxins (p < 0.05). In the in vivo study, pathological examination revealed that the kidney tissue of mice exposed to the combined toxins showed signs of glomerular atrophy. The contents of oxidative stress-related indicators were significantly increased in the kidney tissue (p < 0.05). These findings suggest that the combined toxins cause significant oxidative damage to mouse kidneys. The study highlights the importance of considering the combined effects of mycotoxins in animal feed, particularly AFB1 and T-2, which can lead to severe nephrotoxicity and oxidative stress in PK15 cells and mouse kidneys. The findings have important implications for animal feed safety and regulatory policy.

Clinical utility of RT-PCR in assessing HER 2 gene expression versus traditional IHC and FISH in breast cancer patients

BACKGROUND

IHC and FISH are used for categorizing HER 2 status in breast cancer at the protein and DNA level, respectively. HER 2 expression at the RNA level is quantitative, cheaper, easier to standardize and free from interobserver variation.

METHODS

115 consecutive patients were tested by IHC, FISH and RT-PCR (test cohort). Assuming FISH result to be the response variable, ROC curves for RT-PCR ratio were analyzed to label HER 2 negative, equivocal and positive cases as RT-PCR score 1, 2 and 3, respectively. Inter-relationships between RT-PCR, IHC and FISH were defined. 'Clinical benefit' of a test was defined as proportion of patients labeled unequivocally as HER 2 positive or negative. Population for 1 year was simulated constraint to previous reports of HER 2 positivity and IHC category distribution by a meta-analysis of previous studies that evaluated concordance between IHC and FISH to determine HER 2 status (simulation cohort). Four diagnostic pathways in the simulation cohort were defined-(1) initial IHC, followed by FISH (conventional pathway); (2) initial RT-PCR, followed by FISH; (3) initial IHC, followed by RT-PCR and then by FISH; (4) initial RT-PCR, followed by IHC and then by FISH. The clinical benefit of IHC and RT-PCR in the four pathways was analyzed and sensitivity analysis for incremental cost-effectiveness ratio and cost-benefit comapring RT-PCR against IHC, both as first-line tests and among those with IHC score 2 as a reflex second-line test was performed by the Monte Carlo technique.

FINDINGS

115 patients comprised the study population. While none with IHC score of 0 or 1 was FISH positive for HER 2, all cases with IHC score of 3 were FISH positive. 43 cases were assigned IHC score of 2. Thus, 72 patients benefited from the initial IHC testing [clinical benefit 62.6%], with the overall concordance between IHC and FISH being 100% for those with IHC score of 0, 1 and 3 (conclusive IHC categories). For RT-PCR with 100% concordance, 15.7% (115-97 = 18) patients would have benefited from RT-PCR testing if it was used as a first-line test. If RT-PCR would have been used as a second-line test among those with IHC score 2 (n = 43), then only 6 patients would have been assigned a conclusive RT-PCR category (category 1 or 3) translating to a clinical benefit of 14% (6/43) as a second-line test. As a second-line test it had 51% probability to prove more cost-effective than the conventional pathway, provided the cost of RT-PCR was 0.4 times the cost of IHC. Also in a three-step pathway, RT-PCR upfront would have 56% probability of higher cost-benefit provided the cost of RT-PCR was 0.1 times the cost of IHC.

CONCLUSION

RT-PCR results were found to be suboptimal to IHC in terms of discriminative ability and clinical benefit; thus, it is unlikely to replace IHC as a first-line test in the near future.

Evaluation of HER2 Gene Status in Breast Cancer Samples with Indeterminate Fluorescence in Situ Hybridization by Quantitative Real-Time PCR

Administration of drugs targeting HER2 (official symbol ERBB2) is an important component of therapy for breast cancer patients with HER2 amplification/overexpression as determined by in situ hybridization (ISH) and immunohistochemistry (IHC). In approximately 5% of breast cancers, ISH assays fail. In these cases, HER2 protein expression is evaluated by IHC alone that may yield false negatives/positives for poor-quality samples. Therefore, we developed a method that was based on quantitative real-time PCR applicable for DNA from formalin-fixed, paraffin-embedded tissue samples. Its limit of detection was determined with breast cancer cell lines and validated with 223 breast cancer patient samples. On the basis of comparisons with fluorescent ISH (FISH) and IHC data, the sensitivity of the new method was 94.2% and 95.1%, its specificity was 100% and 99.1%, and overall concordance between results obtained with the quantitative real-time PCR method and FISH/IHC was 97.6% for both methods. The quantitative real-time PCR method was then used to evaluate the HER2 status of 198 of 3696 breast cancer tissues that yielded indeterminate FISH results. The HER2 copy number was successfully determined in 69.2% of these indeterminate samples. Thus, the DNA-based technique appears to be a specific, sensitive method for determining HER2 copy numbers when the FISH assay fails, which may complement IHC tests.

Validation of a postfixation tissue storage and transport medium to preserve histopathology and molecular pathology analyses (total and phosphoactivated proteins, and FISH)

Tumor biomarker studies are integral to oncology clinical trials but may yield artifactual results owing to variation in sample procurement and processing. Ethanol, 70% vol/vol, was validated as a sample transport medium using markers of the PI3K/Akt/mTOR pathway. BT474 tumor xenografts were excised and slices were immediately placed into formaldehyde and fixed for 24 hours. Fixed tissue slices were immediately processed into paraffin or transferred to 70% vol/vol ethanol and stored at room temperature for 1, 2, and 4 weeks before further processing. Freshly cut tissue sections were evaluated for pAKT(S473), HER2, pHER-2(Y1248), pS6(S235/236), and pS6(S240/244), Ki-67, and HER2 by fluorescence in situ hybridization and stained with H&E and Masson trichrome. No significant changes were observed when comparing samples stored in 70% ethanol for up to 4 weeks with immediately processed tissue. Ethanol, 70% vol/vol, provides a safe storage medium for formaldehyde-fixed tumor tissue, facilitating sample transport during multicenter clinical trials.

Phase II Study of Lapatinib in Recurrent or Metastatic Epidermal Growth Factor Receptor and/or erbB2 Expressing Adenoid Cystic Carcinoma and Non–Adenoid Cystic Carcinoma Malignant Tumors of the Salivary Glands

Purpose

Expression of erbB2 and/or epidermal growth factor receptor (EGFR) is associated with biologic aggressiveness and poor prognosis in malignant salivary gland tumors (MSGTs). This phase II study was conducted to determine the antitumor activity of lapatinib, a dual inhibitor of EGFR and erbB2 tyrosine kinase activity, in MSGTs.

Patients and Methods

Patients with progressive, recurrent, or metastatic adenoid cystic carcinoma (ACC) immunohistochemically expressing at least 1+ EGFR and/or 2+ erbB2 were treated with lapatinib 1,500 mg daily, in a two-stage cohort. Patients with non-ACC MSGTs were treated as a separate single-stage cohort.

Results

Of 62 patients screened, 29 of 33 (88%) ACC and 28 of 29 (97%) non-ACC patients expressed EGFR and/or erbB2. Forty patients with progressive disease were enrolled onto the study. Among 19 assessable ACC patients, there were no objective responses, 15 patients (79%) had stable disease (SD), nine patients (47%) had SD ≥ 6 months, and four patients (21%) had progressive disease (PD). For 17 assessable non-ACC patients, there were no objective responses, eight patients (47%) had SD, four patients (24%) had SD ≥ 6 months, and nine patients (53%) had PD. The most frequent adverse events were grade 1 to 2 diarrhea, fatigue, and rash. Eight paired tumor biopsies for correlative studies were procured; results did not correlate with clinical outcome.

Conclusion

Although no responses were observed, lapatinib was well tolerated, with prolonged tumor stabilization of ≥ 6 months in 36% (95% CI, 21% to 54%) of assessable patients. The antitumor effects of lapatinib in MGSTs appear mainly cytostatic, hence evaluation of other molecular targeted agents, or combinations with lapatinib, may be considered. Continued efforts should be made to gain better understanding into the biology of this heterogeneous group of malignancies.

HER-2/neu overexpression in patients with radically resected nonsmall cell lung carcinoma. Impact on long-term survival

BACKGROUND

Using immunohistochemistry, the authors prospectively investigated the expression of HER-2/neu protein in radically resected specimens of nonsmall cell lung carcinoma (NSCLC) and evaluated its impact on long-term prognosis.

METHODS

Between January 1991 and February 1992, surgical specimens from 130 consecutive patients who underwent radical resection for NSCLC (60 squamous cell carcinoma, 48 adenocarcinoma cases, and 22 large cell carcinomas) and that were staged (according to the TNM staging system) pathologically as Stage I (41 cases [32%]), Stage II (37 cases [28%]), and Stage IIIA (52 cases [40%]) were investigated for the expression of HER-2/neu using an avidin-biotin complex immunohistochemical technique. A semiquantitative four-stage grading system was used (0%, 1-5%, 6-20%, and > 20% positive cells) and an average number of 1500 cells/section was considered. Data were correlated with clinical and pathologic variables.

RESULTS

Normal bronchial tissue was found to be completely negative for HER-2/neu expression whereas 21 of the 130 tumor specimens (16%) were positive (range 1-> 20%). HER-2/neu positivity did not appear to differ significantly among pathologic stages and histotypes. Using a predetermined cutoff value of 5% positive cells, 15 tumor specimens (12%) were found to be above this value. The median survival time (85 weeks vs. 179 weeks) and overall survival rate were significantly lower in patients with > 5% HER-2/neu-positive tumors (hazard ratio for the group with > 5% positive cells: 2.94, 95% confidence interval, 1.62-5.34; P < 0.0004). On multivariate analysis, HER-2/neu and extent of tumor emerged as independent factors for disease-related mortality.

CONCLUSIONS

In NSCLC, the negative impact of HER-2/neu overexpression on survival was maintained in the long-term follow-up of radically resected patients. HER-2/neu overexpression may be a valuable prognostic factor as well as a potential target for biologic therapies.

IFN-gamma affects homing of diabetogenic T cells

IFN-gamma is a cytokine with pleiotropic functions that participates in immune and autoimmune responses. The lack of IFN-gamma is known to delay the development of autoimmune diabetes in nonobese diabetic (NOD) mice. Splenocytes from diabetic NOD and IFN-gamma knockout (KO) NOD mice transfer diabetes into NOD recipients equally well. However, adoptive transfer of diabetogenic T cells from NOD mice into NOD.IFN-gamma-KO or NOD mice lacking beta-chain of IFN-gamma receptor (NOD.IFN-gammaRbeta-KO) appeared to be much less efficient. We found that IFN-gamma influences the ability of diabetogenic cells to penetrate pancreatic islets. Tracing in vivo of insulin-specific CD8+ T cells has shown that homing of these cells to the islets of Langerhans was affected by the lack of IFN-gamma. While adhesion of insulin-specific CD8+ cells to microvasculature was normal, the diapedesis was significantly impaired. This effect was reversible by treatment of the animals with rIFN-gamma. Thus, IFN-gamma may, among other effects, influence immune and autoimmune responses by supporting the homing of activated T cells.

The HER-2/neu oncogene in tumors of the gastrointestinal tract

The HER-2/neu oncogene is localized to chromosome 17q and shares significant homology with the epidermal growth factor receptor. As a result of its potential role in the selection of therapy, HER-2/neu testing has reached near-standard-of-practice status in breast cancer. There is considerable interest in HER-2/neu as a prognostic factor and target of therapy in tumors of the gastrointestinal tract. In this review of HER-2/neu expression in esophageal squamous cell carcinoma and adenocarcinomas of the esophagus, stomach, and colon, a wide range of expression of HER-2/neu from 0 to 83% likely reflects both differences in methods and reagents, as well as study bias associated with patient selection (i.e., early versus advanced disease). For esophageal squamous cell carcinoma, little information exists as to the prognostic significance of HER-2/neu expression. In adenocarcinoma associated with Barrett's esophagus there is contradictory data. However, most of the information available indicates that this marker has significant prognostic value. In gastric adenocarcinoma, the wide expression range may truly reflect patient selection because HER-2/neu positivity appears linked to advanced rather than early disease with limited invasion. The majority of studies favor a significant prognostic value of HER-2/neu status for this tumor. Finally, in colorectal cancer HER-2/neu overexpression also appears to be a significant adverse outcome indicator as judged by the current published literature. In conclusion, given that either HER-2/neu protein overexpression or gene amplification is associated with approximately one-fourth of all gastrointestinal tract malignancies, strategies designed to employ the marker in therapy selection appear warranted. During the next several years it will not be surprising to see these tumors treated with antiHER-2/neu modalities such as Herceptin, likely in combination with other agents initially for patients with advanced disease, and possibly for individuals with high-risk lesions in an adjuvant setting.

Multiple molecular marker testing (p53, C-Ki-ras, c-erbB-2) improves estimation of prognosis in potentially curative resected non-small cell lung cancer

A prospective study was performed in patients with non-small cell lung cancer (NSCLC) to evaluate the prognostic importance of multiple molecular marker (p53, c-Ki-ras, c-erbB-2) testing. 103 patients with potentially curative resections (RO resection) for NSCLC in histopathological stages I-IIIA were included. SSCP analysis and DNA sequencing for p53 and c-Ki-ras genes were performed on paired tumour and normal lung tissue samples and immunohistochemistry (c-erbB-2) was done on frozen tissue sections with a specific anti-c-erbB-2 monoclonal antibody. 46/103 (44.6%) NSCLC showed p53 mutations and 17/103 (16.5%) c-Ki-ras mutations including 12/37 (32.4%) adenocarcinomas. Overexpression of c-erbB-2 (p185) was detected in 56/103 (54.4%) tumours. 24/103 (23.3%) NSCLC were negative for alterations in all 3 parameters (c-Ki-ras, p53 and p185) whereas 79/103 (76.7%) were positive for at least one of the 3 parameters. In a regression model including a multiple molecular marker parameter (negative for all 3 markers versus positive for at least one marker), histopathological stage (P<0.00001), respectively the pT (P<0.01) and pN (P<0.00001) categories and the multiple molecular marker parameter (P<0.01) were of significant prognostic importance. This study demonstrates that testing 3 molecular markers (c-Ki-ras, p53 and c-erbB-2) improves estimation of prognosis compared to single marker testing and appears to define low (82.6%+/-7.9% 5-year survival) and high risk (40.2%+/-5.5% 5-year survival) groups for treatment failure in potentially curative (RO) resected NSCLC.

Prognostic significance of HER-2/neu gene amplification status by fluorescence in situ hybridization of prostate carcinoma

BACKGROUND

HER-2/neu gene amplification, established as a prognostic factor in breast carcinoma and other cancers, has not been correlated with outcome in prostate carcinomas (PCs).

METHODS

HER-2/neu gene amplification was determined by automated fluorescence in situ hybridization (FISH) using a unique sequence cosmid probe on 113 formalin fixed, paraffin embedded 4-microns tissue sections and the results compared with tumor grade, DNA ploidy, HER-2/neu protein expression by immunohistochemistry (IHC), serum prostate specific antigen, pathologic stage, and postoperative disease recurrence (mean follow-up of 44 months).

RESULTS

HER-2/neu gene amplification by FISH (41% of PCs) correlated with tumor grade (P = 0.001) and DNA ploidy status (P = 0.0003). HER-2/neu protein overexpression by IHC (29% of PCs) correlated with grade (P = 0.03), but not with DNA ploidy. A trend for similar HER-2/neu status in each PC by IHC and FISH did not reach statistical significance (P = 0.25). On univariate analysis, HER-2/neu amplification by FISH (P = 0.029), tumor grade (P = 0.013), and DNA ploidy (P = 0.016) correlated with postoperative disease recurrence. HER-2/neu expression by IHC did not correlate with outcome. On multivariate analysis, grade (P = 0.0001) and ploidy (P = 0.001) were independent outcome predictors; HER-2/neu amplification by FISH reached near-independent significance (P = 0.125).

CONCLUSIONS

HER-2/neu gene amplification by FISH on archival PCs significantly correlates with grade and DNA ploidy status, is more sensitive than IHC in detecting HER-2/neu gene abnormalities, predicts postoperative disease recurrence, and may prove important in planning therapy for patients with prostate carcinoma.

Immunohistochemical detection of p53 and c-erbB-2 in oesophageal carcinoma; no correlation with prognosis

TNM staging of oesophageal cancer provides significant prognostic information but its clinical impact is limited as many patients present with advanced disease (i.e. T3N1). Additional prognostic markers may help separate those with 'good' and 'bad' prognosis tumours and so help with decisions such as selection for adjuvant therapy. p53 and c-erbB-2 overexpression may correlate with poor prognosis in oesophageal cancer, but this is uncertain. This study aimed to investigate the value of these biomarkers as prognostic indicators in resected oesophageal cancer. Two hundred and five oesophageal tumours (127 adenocarcinoma, 78 squamous) resected by a single surgeon between June 1979 and January 1991 were investigated for p53 and c-erbB-2 overexpression using DO-7 and CB-11 immunohistochemistry. Patient survival was analysed by Kaplan-Meir life tables. Median survival was 61 weeks (range: 5-747) and survival diminished significantly with increasing UICC stage (P < 0.0001). Sixty-eight per cent of squamous tumours and 66% of adenocarcinomas overexpressed p53 but there was no statistically significant correlation with prognosis. Twenty-six per cent of squamous tumours and 23% of adenocarcinomas overexpressed c-erbB-2, but again this did not correlate with survival. p53 and c-erbB-2 are commonly overexpressed in oesophageal cancer but do not appear to be related to prognosis in this large series of resected oesophageal cancers and other candidate biomarkers must be sought.

c-erbB-2 expression in FNAB smears and matched surgical specimens of breast cancer

Most of the data regarding the significance of c-erbB-2 oncogene expression as a prognostic marker in breast cancer have been generated in many large retrospective studies by retrieving the corresponding oncoprotein in archival paraffin embedded sections. Recently, employing fresh breast cancer cells obtained by means of fine-needle aspiration biopsy, we found a rate of c-erbB-2 positive breast tumors (58%) higher than that reported in paraffin-embedded tissue sections by others studies. The present analysis was undertaken to investigate the impact of routine tissue processing on the preservation of the c-erbB-2 immunoreactivity. This issue was addressed by assessing the relative rate of c-erbB-2 oncoprotein immunodetection on FNAB smears and matched surgical specimens of breast cancer. The expression of c-erbB-2 oncoprotein was evaluated using the alkaline phosphate-anti-alkaline phosphatase (APAAP) technique in 54 breast aspirates and corresponding surgical specimens of primary breast cancer. Twenty-six (48%) smears and 23 (43%) matched paraffin sections gave specific signal for c-erbB-2 oncoprotein. The slightly higher incidence of c-erbB-2 expression found on smears seems to be mainly due to the better antigen preservation in the fresh cytological preparations. We conclude that routine histological processing may affect c-erbB-2 immunoreactivity; therefore, in mounting prospective studies, it is advisable to assess c-erbB-2 status in fresh tissue. Moreover, the assessment of c-erbB-2 expression on aspirate samples may yield additional information to the pre-surgical prognostic evaluation of breast cancer diagnosed by FNAB.

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.