Expression of epidermal growth factor receptor in normal colorectal mucosa, adenoma, and carcinoma

Recommendations for Specimen and Therapy Selection in Colorectal Cancer

INTRODUCTION

Next-generation sequencing has emerged as a clinical tool for the identification of actionable mutations to triage advanced colorectal cancer patients for targeted therapies. The literature is conflicted as to whether primaries or their metastases should be selected for sequencing. Some authors suggest that either site may be sequenced, whereas others recommend sequencing the primary, the metastasis, or even both tumors. Here, we address this issue head on with a meta-analysis and provide for the first time a set of sensible recommendations to make this determination.

METHODS

From our own series, we include 43 tumors from 13 patients including 14 primaries, 10 regional lymph node metastases, 17 distant metastases, and two anastomotic recurrences sequenced using the 50 gene Ion AmpliSeq cancer NGS panel v2.

RESULTS

Based on our new cohort and a meta-analysis, we found that ~ 77% of patient-matched primary-metastatic pairs have identical alterations in these 50 cancer-associated genes.

CONCLUSIONS

Low tumor cellularity, tumor heterogeneity, clonal evolution, treatment status, sample quality, and/or size of the sequencing panel accounted for a proportion of the differential detection of mutations at primary and metastatic sites. The therapeutic implications of the most frequently discordant alterations (TP53, APC, PIK3CA, and SMAD4) are discussed. Our meta-analysis indicates that a subset of patients who fail initial therapy may benefit from sequencing of additional sites to identify new actionable genomic abnormalities not present in the initial analysis. Evidence-based recommendations are proposed.

FoxM1: Repurposing an oncogene as a biomarker

The past few decades have witnessed a tremendous progress in understanding the biology of cancer, which has led to more comprehensive approaches for global gene expression profiling and genome-wide analysis. This has helped to determine more sophisticated prognostic and predictive signature markers for the prompt diagnosis and precise screening of cancer patients. In the search for novel biomarkers, there has been increased interest in FoxM1, an extensively studied transcription factor that encompasses most of the hallmarks of malignancy. Considering the attractive potential of this multifarious oncogene, FoxM1 has emerged as an important molecule implicated in initiation, development and progression of cancer. Bolstered with the skill to maneuver the proliferation signals, FoxM1 bestows resistance to contemporary anti-cancer therapy as well. This review sheds light on the large body of literature that has accumulated in recent years that implies that FoxM1 neoplastic functions can be used as a novel predictive, prognostic and therapeutic marker for different cancers. This assessment also highlights the key features of FoxM1 that can be effectively harnessed to establish FoxM1 as a strong biomarker in diagnosis and treatment of cancer.

The level of epidermal growth factor receptors expression is correlated with the advancement of colorectal adenoma: validation of a surface biomarker

INTRODUCTION

Data about the expression of Epidermal Growth Factor Receptors (EGFRs) in colorectal adenomas remain scarce.

RESULTS

101 patients were enrolled including 53 controls. All adenomas (n = 38) and CRC (n = 5) were EGFR positive. Hyperplastic polyps (HP) (n = 8) and control colons (n = 53) were EGFR negative in half of cases (p < 0.0001). A well significant gradient of increased EGFR expression was observed between adjacent mucosa, hyperplastic lesions, low grade dysplasia (LGD) (n = 30), high grade dysplasia (HGD) adenomas (n = 9) and cancers (p < 0.0001). EGFR overexpression was reported in 100% of cancers, 77.8% of HGD, and 10% of LGD adenomas. By multivariate analysis in adenomas, associated factors with EGFR overexpression were HGD and tubulo-villous feature.

MATERIALS AND METHODS

All patients undergoing colonoscopy in the university center of Saint-Etienne were eligible to the study from December 2015 to March 2016. In patients with colorectal neoplasia (lesions group), biopsies were performed on the lesion before its resection, and on the adjacent and distal colon mucosa. In control group, biopsies were performed in the right and left side colon. The EGFR expression was assessed by immunohistochemical scores (Goldstein grade, intensity of staining, composite score), using a primary mouse monoclonal antibody (EGFR, clone 113, Novocastra). Outcomes were compared using Kruskal-Wallis and/or Mann-Whitney-U tests, appropriately. The associated clinical, endoscopic and histological factors with EGFR overexpression (composite score ≥ 6) were assessed for adenomas by logistic regression.

CONCLUSIONS

EGFR are early involved in colorectal carcinogenesis, and their expression is strongly correlated to the neoplasia stage, leading to validate EGFR as an interesting surface biomarker of adenomas.

Novel targets for natural killer/T-cell lymphoma immunotherapy

Extranodal natural killer/T-cell lymphoma, nasal type (NKTL) is a rare but highly aggressive Epstein-Barr virus-related malignancy, which mainly occurs in nasopharyngeal and nasal/paranasal areas. In addition to its high prevalence in Asian, Central American and South American populations, its incidence rate has been gradually increasing in Western countries. The current mainstay of treatment is a combination of multiple chemotherapies and irradiation. Although chemoradiotherapy can cure NKTL, it often causes severe and fatal adverse events. Because a growing body of evidence suggests that immunotherapy is effective against hematological malignancies, this treatment could provide an alternative to chemoradiotherapy for treatment of NKTL. In this review, we focus on how recent findings could be used to develop efficient immunotherapies against NKTL.

Angiogenesis, immune system and growth factors: new targets in colorectal cancer therapy

Colorectal cancer is the second most common malignant human neoplasia. Over recent years, many efforts have been performed in order to develop and improve therapeutic protocols, and many advances have been accomplished in both the field of adjuvant and palliative therapy. Most of the chemotherapic agents currently used in the clinical setting are the products of decades of research aimed at inhibiting the uncontrolled growth of dysplastic cells. However, new frontiers in this field have recently been opened, with the identification of key molecules involved in physiologic mechanisms that are of fundamental importance for cancer development and progression. Tumor-induced angiogenesis, the cancer-immune system crosstalk and the effect of growth factors on dysplastic cells represent new fields of investigation for anticancer therapy.

Overexpression of epidermal growth factor receptor as a prognostic factor in colorectal cancer on the basis of the Allred scoring system

BACKGROUND

Overexpression of epidermal growth factor receptor (EGFR) is found in many types of neoplasms. The aim of the study was to evaluate EGFR expression in colorectal cancer (CRC) specimens and to determine whether EGFR expression correlates with clinicopathological data and overall survival.

PATIENTS AND METHODS

Tissue specimens from 181 consecutive CRC patients treated at the Military Institute of Medicine in 2006-2010 were collected and examined for EGFR expression, by immunohistochemistry staining. The staining intensity and percentage of cells with membranous EGFR expression were scored and then grouped according to the parameters of the Allred Scoring system. Cutoff values were subjected to further statistical analysis. Univariate tests and a multivariate Cox proportional hazards model were used in data analysis.

RESULTS

EGFR was overexpressed in 96 of 181 CRC specimens (53%). EGFR expression was not correlated with other clinicopathological variables. On univariate analysis, overexpression of EGFR, determined by PS (percentage score) (>3) and total score (sum of PS and intensity score) (>4), was associated with poor overall survival. On multivariate analysis, EGFR overexpression (PS > 3) was an independent adverse prognostic factor (hazard ratio [HR] 1.62; 95% confidence interval [CI]: 1.03-2.53). Elevated carcinoembryonic antigen (CEA) serum concentration before treatment, performance status (Word Health Organization [WHO]-2), and tumor localized in colon and liver metastases were also independent unfavorable prognostic factors.

CONCLUSION

EGFR overexpression (PS > 3) in a CRC patient population was an independent adverse prognostic factor. Implementation of the Allred Scoring system criteria into clinical practice might facilitate treatment decisions in CRC patients.

Expression of EGFR, HER2, phosphorylated ERK and phosphorylated MEK in colonic neoplasms of familial adenomatous polyposis patients

PURPOSE

The expression of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) is associated with poor prognosis in sporadic colorectal carcinoma (CRC). EGFR inhibitors are approved for the treatment of refractory CRC. The aim of this study was to investigate the expression of EGFR and HER2 and downstream extracellular signal regulated kinase (ERK) and mitogen activated protein kinase (MAPK) in non-neoplastic colonic mucosa, adenomas and carcinomas from familial adenomatous polyposis coli (FAP) patients, exploring the expression along the adenoma-carcinoma sequence.

METHODS

The expression of EGFR, HER2, phosphorylated MAPK/ERK kinase (pMEK) and phosphorylated ERK (pERK) proteins was studied by immunohistochemistry in samples of colonic non-neoplastic mucosa (n = 65), adenomas (n = 149) and adenocarcinomas (n = 16) from each of the 16 FAP patients.

RESULTS

For HER2, only weak cytoplasmic expression was seen in 8% of adenomas, 6% of carcinomas and 3% of the non-neoplastic mucosa. EGFR was expressed in non-neoplastic mucosa, adenomas and carcinomas with a statistically significant increase in expression in adenomas compared with non-neoplastic mucosa (p < 0.001). There was also a statistically significant increase in nuclear staining intensity for pERK (p < 0.001) and pMEK (p < 0.001) in adenomas compared to non-neoplastic mucosa.

CONCLUSIONS

This is the first study investigating the expression of these receptors in non-neoplastic mucosa, adenomas and carcinomas from FAP patients. HER2 is not upregulated in the tumours of FAP patients, while EGFR appears to be upregulated in most adenomas and carcinomas, with associated upregulation of pERK and pMEK. We conclude that EGFR and downstream members of its signalling pathway, but not HER2, may be potential therapeutic targets in FAP patients.

Carcinoembryonic antigen is the preferred biomarker for in vivo colorectal cancer targeting

Background:

Colorectal cancer-specific biomarkers have been used as molecular targets for fluorescent intra-operative imaging, targeted PET/MRI, and selective cytotoxic drug delivery yet the selection of biomarkers used is rarely evidence-based. We evaluated sensitivities and specificites of four of the most commonly used markers: carcinoembryonic antigen (CEA), tumour-associated glycoprotein-72 (TAG-72), folate receptor-α (FRα) and Epithelial growth factor receptor (EGFR).

Methods:

Marker expression was evaluated semi-quantitatively in matched mucosal and colorectal cancer tissues from 280 patients using immunohistochemistry (scores of 0–15). Matched positive and negative lymph nodes from 18 patients were also examined.

Results:

Markers were more highly expressed in tumour tissue than in matched normal tissue in 98.8%, 79.0%, 37.1% and 32.8% of cases for CEA, TAG-72, FRα and EGFR, respectively. Carcinoembryonic antigen showed the greatest differential expression, with tumours scoring a mean of 10.8 points higher than normal tissues (95% CI 10.31–11.21, P<0.001). Similarly, CEA showed the greatest differential expression between positive and negative lymph nodes. Receiver operating characteristic analyses showed CEA to have the best sensitivity (93.7%) and specificity (96.1%) for colorectal cancer detection.

Conclusion:

Carcinoembryonic antigen has the greatest potential to allow highly specific tumour imaging and drug delivery; future translational research should aim to exploit this.

Alteration of EGFR spatiotemporal dynamics suppresses signal transduction

The epidermal growth factor receptor (EGFR), which regulates cell growth and survival, is integral to colon tumorigenesis. Lipid rafts play a role in regulating EGFR signaling, and docosahexaenoic acid (DHA) is known to perturb membrane domain organization through changes in lipid rafts. Therefore, we investigated the mechanistic link between EGFR function and DHA. Membrane incorporation of DHA into immortalized colonocytes altered the lateral organization of EGFR. DHA additionally increased EGFR phosphorylation but paradoxically suppressed downstream signaling. Assessment of the EGFR-Ras-ERK1/2 signaling cascade identified Ras GTP binding as the locus of the DHA-induced disruption of signal transduction. DHA also antagonized EGFR signaling capacity by increasing receptor internalization and degradation. DHA suppressed cell proliferation in an EGFR-dependent manner, but cell proliferation could be partially rescued by expression of constitutively active Ras. Feeding chronically-inflamed, carcinogen-injected C57BL/6 mice a fish oil containing diet enriched in DHA recapitulated the effects on the EGFR signaling axis observed in cell culture and additionally suppressed tumor formation. We conclude that DHA-induced alteration in both the lateral and subcellular localization of EGFR culminates in the suppression of EGFR downstream signal transduction, which has implications for the molecular basis of colon cancer prevention by DHA.

Squamous-cell carcinoma of the anal canal: room for improvement with targeted therapy

Carcinoma of the anal canal is a rare disease accounting for 1-5% of gastrointestinal tract malignancies. However, its incidence is increasing worldwide. Chemoradiation is the standard treatment for most patients with squamous-cell carcinoma of the anal canal and was first described by Nigro et al. Since then, no other effective treatment was developed. Patients with metastatic disease should be considered candidates for clinical trials. New treatment strategies, including molecular target therapies, are warranted in order to improve disease control. Despite the rarity of this disease, it is urgent to improve its treatment by introducing targeted therapy in the arena.

Noninvasive radiofrequency field destruction of pancreatic adenocarcinoma xenografts treated with targeted gold nanoparticles

PURPOSE

Pancreatic carcinoma is one of the deadliest cancers with few effective treatments. Gold nanoparticles (AuNP) are potentially therapeutic because of the safety demonstrated thus far and their physiochemical characteristics. We used the astounding heating rates of AuNPs in nonionizing radiofrequency (RF) radiation to investigate human pancreatic xenograft destruction in a murine model.

EXPERIMENTAL DESIGN

Weekly, Panc-1 and Capan-1 human pancreatic carcinoma xenografts in immunocompromised mice were exposed to an RF field 36 hours after treatment (intraperitoneal) with cetuximab- or PAM4 antibody-conjugated AuNPs, respectively. Tumor sizes were measured weekly, whereas necrosis and cleaved caspase-3 were investigated with hematoxylin-eosin staining and immunofluorescence, respectively. In addition, AuNP internalization and cytotoxicity were investigated in vitro with confocal microscopy and flow cytometry, respectively.

RESULTS

Panc-1 cells demonstrated increased apoptosis with decreased viability after treatment with cetuximab-conjugated AuNPs and RF field exposure (P = 0.00005). Differences in xenograft volumes were observed within 2 weeks of initiating therapy. Cetuximab- and PAM4-conjugated AuNPs demonstrated RF field-induced destruction of Panc-1 and Capan-1 pancreatic carcinoma xenografts after 6 weeks of weekly treatment (P = 0.004 and P = 0.035, respectively). There was no evidence of injury to murine organs. Cleaved caspase-3 and necrosis were both increased in treated tumors.

CONCLUSIONS

This study demonstrates a potentially novel cancer therapy by noninvasively inducing intracellular hyperthermia with targeted AuNPs in an RF field. While the therapy is dependent on the specificity of the targeting antibody, normal tissues were without toxicity despite systemic therapy and whole-body RF field exposure.

Expression of membranous epidermal growth factor receptor in colorectal adenocarcinoma and its correlation with clinicopathological features

The aim of this study was to investigate the expression of membranous epidermal growth factor receptor in colorectal adenocarcinoma and it's correlation with clinicopathological features. Fifty formalin-fixed, paraffin embedded archival specimens of colorectal cancer were included randomly as cases. Immunohistochemical staining was performed to assess EGFR expression. The results were correlated with the clinicopathological features of colorectal tumor tissues. More than 1% of membranous EGFR expression was found in 24 (48%) of cancer specimens. The immunoreactions intensity was classified as weak, moderate and strong representing 2, 22 and 24%, respectively. According to multivariate analysis, EGFR expression was not significantly associated with age, sex, tumor site, stage, grade and type of tumor in cases. These results suggest that the assessment of EGFR expression in colorectal cancer by conventional immunohistochemistry has not proven its predictive value and can not be useful to predict about outcome of patients.

Practical and molecular evaluation of colorectal cancer: new roles for the pathologist in the era of targeted therapy

CONTEXT

Colorectal cancer is the third most common cancer and the fourth most common cause of cancer death worldwide. Patient cases are discussed in multidisciplinary meetings to decide on the best management on an individual basis. Until recently, the main task of the pathologist in such teams was to provide clinically useful reports comprising staging of colorectal cancer in surgical specimens. The advent of total mesorectal excision and the application of anti-epidermal growth factor receptor (EGFR)-targeted therapies for selected patients with metastasized colorectal cancer have changed the role of the pathologist.

OBJECTIVES

To present the traditional role of the pathologist in the multidisciplinary team treating patients with colorectal cancer, to address the technique of total mesorectal excision and its implications for the evaluation of surgical specimens, to offer background information on the various EGFR-targeted therapies, and to review the currently investigated tissue biomarkers assumed to be predictive for efficacy of such therapies, with a focus on the role of the pathologist in determining the status of such biomarkers in individual tumors.

DATA SOURCES

This article is based on selected articles pertaining to biopsy evaluation of colorectal carcinoma and reviews of EGFR-targeted therapies for this cancer. All references are accessible via the PubMed database (US National Library of Medicine and the National Institutes of Health).

CONCLUSIONS

Pathologists play an increasingly important role in the diagnosis and management of colorectal cancer because of the advent of new surgical techniques and of targeted therapies. It is expected that this role will increase further in the near future.

A review of the most promising biomarkers in colorectal cancer: one step closer to targeted therapy

Rapidly growing insights into the molecular biology of colorectal cancer (CRC) and recent developments in gene sequencing and molecular diagnostics have led to high expectations for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on molecular biomarkers are contradictory in their findings and the current reality is that no molecular marker, other than the KRAS gene in the case of epidermal growth factor receptor (EGFR)- targeted therapy for metastatic disease, has made it into clinical practice. Many markers investigated suffer from technical shortcomings, resulting from lack of quantitative techniques to capture the impact of the molecular alteration. This understanding has recently led to the more comprehensive approaches of global gene expression profiling or genome-wide analysis to determine prognostic and predictive signatures in tumors. In this review, an update of the most recent data on promising biological prognostic and/or predictive markers, including microsatellite instability, epidermal growth factor receptor, KRAS, BRAF, CpG island methylator phenotype, cytotoxic T lymphocytes, forkhead box P3-positive T cells, receptor for hyaluronic acid-mediated motility, phosphatase and tensin homolog, and T-cell originated protein kinase, in patients with CRC is provided.

Sulindac metabolites induce proteosomal and lysosomal degradation of the epidermal growth factor receptor

The epidermal growth factor receptor (EGFR) is a member of the ErbB family of receptor tyrosine kinases. In response to ligand, EGFR is internalized and degraded by the ubiquitin-proteasome/lysosome pathway. We previously reported that metabolites of the nonsteroidal anti-inflammatory drug sulindac downregulate the expression of EGFR and inhibit basal and EGF-induced EGFR signaling through extracellular signal-regulated kinase 1/2. We now have evaluated the mechanisms of sulindac metabolite-induced downregulation of EGFR. EGF-induced downregulation of EGFR occurs within 10 minutes and lasts for 24 hours. By contrast, downregulation of EGFR by sulindac sulfide and sulindac sulfone was first evident at 4 and 24 hours, respectively, with maximal downregulation at 72 hours. Pretreatment with either the lysosomal inhibitor chloroquine or the proteosomal inhibitor MG132 blocked sulindac metabolite-induced downregulation of EGFR. Sulindac metabolites also increased the ubiquitination of EGFR. Whereas sulindac metabolites inhibited phosphorylation of EGFR pY1068, they increased phosphorylation of EGFR pY1045, the docking site where c-Cbl binds, thereby enabling receptor ubiquitination and degradation. Immunofluorescence analysis of EGF and EGFR distribution confirmed the biochemical observations that sulindac metabolites alter EGFR localization and EGFR internalization in a manner similar to that seen with EGF treatment. Expression of ErbB family members HER2 and HER3 was also downregulated by sulindac metabolites. We conclude that downregulation of EGFR expression by sulindac metabolites is mediated via lysosomal and proteosomal degradation that may be due to drug-induced phosphorylation at pY1045 with resultant ubiquitination of EGFR. Thus, sulindac metabolite-induced downregulation of EGFR seems to be mediated through mechanism(s) similar, at least in part, to those involved in EGF-induced downregulation of EGFR.

Human epidermal growth factor receptor-2 family in colorectal adenocarcinoma: correlation with survival and clinicopathological findings

BACKGROUND AND PURPOSE

Erb-B1 (epidermal growth factor receptor, EGFR) and Erb-B2 (HER-2) are two of the best-characterized members in the EGFR pathway. In many tumor types, overexpression of these proteins is associated with enhanced malignant potential. The aim of this study was to determine the prognostic impact of EGFR and HER-2 protein expression on colorectal cancer.

METHOD

Immunohistochemistry was carried out in paraffin-embedded specimens of 115 colorectal carcinomas for the assessment of EGFR and HER-2 expression. Immunostaining for EGFR was graded negative, weak or strong according to extension and staining intensity. The results were correlated with traditional clinicopathologic parameters and patients' outcome.

RESULTS

The mean survival time was 64 (range 9-78) months in the EGFR-negative group, 166 (range 2-293) months in the group with a low EGFR expression, and 51 (range 4-71) months in the group with a high EGFR expression. The median survival time was 31 (range 2-114) months in the HER-2 negative group, and 30 (range 4-293) months in the HER-2 positive group. None of the clinicopathologic parameters or patient prognoses had statistically significant association with EGFR or HER-2 expression.

CONCLUSION

Conventional immunohistochemistry was unable to reveal any association between EGFR or HER-2 expression and outcome predicted by the biologic role of EGFR in tumor behavior and the established prognostic role of HER-2 in breast cancer.

LRIG1 expression in colorectal cancer

In the present study the expression of LRIG1 (leucine rich repeats and immunoglobin-like domains 1) and its relation to EGFR (epidermal growth factor receptor) was examined in tumour samples and adjacent non-neoplastic tissues from 30 patients with colorectal cancer. The LRIG1 gene, at chromosome 3p14, encodes an intergral membrane protein, which counteracts signalling by receptor tyrosine kinases belonging to the ERBB (epidermal growth factor receptor) family. LRIG1 is expressed in all tissues and organs analysed to date, including breast, brain, skin, kidney, spleen and colon. Overexpression of EGFR is seen in 70 - 90% of colorectal cancers, and is associated with a poor survival. Western blot analysis showed LRIG1 upregulation in 43% and downregulation in 43% of the colorectal cancers compared to adjacent non-neoplastic tissue. No correlation was evident between LRIG1, analysed by Western Blot and the expression of EGFR analysed by immunohistochemistry. FISH (fluoroscence in situ hybridisAtion) analysis showed increased LRIG1 copy number in one of nine tumours. Four colorectal cancer cell lines demonstrated two LRIG1 gene copies. In conclusion, there was a great heterogeneity in the expression of the LRIG1 protein in colorectal cancer, which was not related to gene dosage of the LRIG1 gene. Further studies can be of interest to evaluate whether alteration in LRIG1 expression in colorectal cancer is of biological or clinical significance.

Epidermal growth factor receptor in colorectal carcinoma: correlation with clinico-pathological prognostic factors

OBJECTIVE

This study was undertaken to determine the relationship between epidermal growth factor receptor (EGFR) status in primary colorectal cancer (CRC) to different clinico-pathological prognostic factors.

METHOD

Seventy-nine primary CRC were studied using four scoring systems: 1- EGFR pharmDx score, 2- score modified from the Hercept test [J Histo cytochem, 52 (2004) 893], 3- two additive scores with different cutoff points [Mod Pathol, 11 (1998) 155], 4- two multiplicative scores with different cutoff points [Ann Oncol, 16 (2005) 102].

RESULTS

More than 10% membranous EGFR reactivity was identified in 46.8% (37/79) of the tumours. The intensity was classified as mild, moderate and strong representing 8.9%, 20.3% and 17.7% respectively. Strong correlation was found between the EGFR pharmDx and the proposed scores, at different cutoff points (P < 0.01). A strong correlation was found between EGFR expression, advanced clinical stage (P < 0.01), nodal involvement (P < 0.01) and lympho-vascular invasion (LV) (P < 0.05) in category I factors, poorly differentiated tumours in IIA (P < 0.05), infiltrative border configuration in IIB (P < 0.01), perineural invasion (PN) in III (P < 0.01), and larger tumours in IV (P < 0.01). Heterogenous staining was present in 46.3% of tumours and was associated with an increased score, LV and PN invasion and advanced clinical stage (P < 0.05).

CONCLUSION

Using a cut-off point of 10%, similar results with different scoring systems were obtained, representing standardization for EGFR interpretation. EGFR expression is correlated with conventional clinico-pathological prognostic factors.

Epidermal Growth Factor Receptor Is Involved in the Development of an Invasive Phenotype in Vulvar Squamous Lesions, but Is Not Related to MIB-1 Immunoreactivity

This study investigated the expression of epidermal growth factor receptor (EGFR) and proliferation as determined by MIB-1 labeling indices (proliferation index [PI]) in 82 cases of vulvar tissues consisting of healthy epithelia (HE) (n = 10), vulvar condylomas (VC; n = 24), high-grade vulvar intraepithelial neoplasias (HG-VIN) of warty and basaloid types (n = 26), invasive keratinizing squamous cell carcinomas (SCCs; n = 22), and differentiated VIN adjacent to SCCs (n = 7) by means of a standard immunohistochemical method using monoclonal antibodies to characterize EGFR expression, with an emphasis on neoplastic transformation and progression, and to relate it to proliferation. The EGFR expression was mainly membranous and--to a lesser degree--cytoplasmic; it was scored for intensity and quantity. The MIB-1 reactivity was exclusively nuclear. High EGFR immunoscores were detected on 6% of HG-VIN and 41% of SCCs. The EGFR immunoexpression increased significantly from healthy epithelia to VCs, VINs (HG-VIN and differentiated VIN taken together), and SCCs (P < 0.0001 [chi2 test]), but was not related to stage, grade, or recurrence in SCCs. There was no statistical significance for EGFR immunoscores and PIs in the groups of VCs (P = 0.1923), VINs (P = 0.0951), and SCCs (P = 0.6896). This study shows the upregulation of EGFR expression in a few warty and basaloid HG-VIN cases and in many SCCs of the vulva. The lack of a relationship with PIs suggests that mechanisms other than proliferation are involved in this process.

Expression of epidermal growth factor receptor in squamous cell carcinomas of the anal canal is independent of gene amplification

Immunohistochemical detection of expression of the epidermal growth factor receptor (EGFR) has been utilized to identify eligible patients with solid malignant tumors, including colorectal adenocarcinoma, for monoclonal antibody therapy (eg, cetuximab). The EGFR status in squamous cell carcinoma of the anal canal, an uncommon malignancy traditionally treated with chemoradiation, has not been well investigated. In this study, 38 primary squamous cell carcinomas of the anal canal were immunohistochemically examined for EGFR expression and analyzed by fluorescence in situ hybridization (FISH) for EGFR gene copy numbers. The results showed a variable degree of EGFR expression in 21 (55%) tumors, among which 13 (62%) cases exhibited a 2+ to 3+ staining pattern according to the Dako EGFR phamDx interpretation guide. There were no significant differences among tumors stratified by stage, degree of keratinization, or tissue block storage times. FISH analysis showed that none of the 34 cases with interpretable results had EGFR gene amplification. Increased gene copy numbers due to polysomy 7 were seen in seven of 18 (39%) cases that expressed EGFR protein and four of 16 (25%) cases that did not (P=0.3876). Ten (56%) tumors with positive EGFR staining showed a balanced disomy 7 pattern and one case with monosomy 7 exhibited strong EGFR expression (3+). These results demonstrate that EGFR is overexpressed in more than one-half of the squamous cell carcinomas of the anal canal through mechanisms other than gene amplification. These observations may have important therapeutic implications since EGFR-based targeted therapies have shown promise for other malignant neoplasms.

Epidermal growth factor receptor signaling in colorectal cancer: preclinical data and therapeutic perspectives

Epidermal growth factor receptor (EGFR) belongs to a family of receptors known as the ErbB family (ErbB tyrosine kinase receptors) which comprises four proteins encoded by the c-erbB proto-oncogene. EGFR is known to activate a cascade of multiple signaling pathways that facilitate tumor growth process. EGFR has been shown to be overexpressed in colorectal cancer patient populations but its prognostic value in colorectal cancer progression remains unclear. The development of a panel of EGFR inhibitors could reduce the proliferation of tumor cells when used alone or in combination with cytotoxic drugs or radiation. This review focuses on the potential role of EGFR signaling in the survival of colorectal tumor cells and the possible modulation of such signaling pathways by EGFR inhibitors so as to increase tumor control or render tumor cells more sensitive to conventional therapy.

Impact of EGFR expression on colorectal cancer patient prognosis and survival

BACKGROUND

Epidermal growth factor receptor (EGFR) is overexpressed in many types of cancers, especially colorectal cancer (CRC), and seems to reflect more aggressive histological and clinical behaviors. The aim of this study was to evaluate EGFR immunohistochemical reactivity in CRC biopsies, and to analyze its relationship with various histological and clinical characteristics and survival.

PATIENTS AND METHODS

A composite EGFR score, obtained by multiplying the grade (% positive cells) by the intensity of labeling (0-9) was used to define patients with low or high EGFR expression whose clinicopathological features were then compared. Univariate tests and multivariate Cox proportional hazards model were applied for data analysis.

RESULTS

Tissue sections from 150 CRC patients with a median follow-up of 40 months were examined. Median patient age at diagnosis was 70 years (range 38-89 years). EGFR reactivity was positive for 143 patients (97%) and high for 118 (80%). According to multivariate analysis, EGFR overexpression was significantly associated with tumor stage, with a higher percentage of EGFR overexpression in T3 than T4 (P=0.003) and not with overall survival.

CONCLUSIONS

EGFR was overexpressed in this CRC patient population and was significantly associated with TNM (tumor-node-metastasis) stage T3. In the context of a new therapeutic strategy using EGFR-targeted therapies, although EGFR remains a controversial prognostic factor, this expression-stage association may play a crucial role in a decision to initiate an adjuvant treatment.

The epidermal growth factor receptor as a target for colorectal cancer therapy

The epidermal growth factor receptor (EGFR) is the prototypical member of the erbB receptor family. The EGFR axis is activated by a variety of ligands that are crucial in the formation and propagation of many tumors, including colorectal cancer, through their effects on cell signaling pathways, cellular proliferation, control of apoptosis, and angiogenesis. The importance of the EGFR axis in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. A variety of targeting strategies to exploit the role of EGFR in tumors have been employed. The most highly developed of these anti-EGFR approaches are the monoclonal antibodies and the tyrosine kinase inhibitors (TKIs). Clinical evaluations of these compounds have yielded some promising results. The role of the EGFR axis in colorectal cancer formation and progression is reviewed and the clinical development of these anticancer EGFR-targeted drugs is reviewed and updated.

The epidermal growth factor receptor as a target for gastrointestinal cancer therapy

The epidermal growth factor receptor (EGFR) is a member of the family of transmembrane protein kinase receptors known as the erbB or HER receptor family. When activated, EGFR phosphorylates and activates other intracellular proteins that affect cell signaling pathways, cellular proliferation, control of apoptosis and angiogenesis. EGFR signaling is best thought of as a network of activating and inactivating proteins with EGFR as the entry point into the network. EGFR overexpression occurs in most GI malignancies and while data are not entirely consistent, EGFR overexpression often confers a poor prognosis in those GI malignancies that have been studied. It often correlates with poorly differentiated histology, more advanced stage and other known poor prognostic markers. The EGFR is a tempting target because of its presence and overexpression on so many tumor types. However, downstream of the EGFR are several proteins that may be activated without EGFR thus allowing blockade to be overcome. Therefore, while blocking the activity of the EGFR protein appears to be a promising anticancer strategy, a simplistic strategy of blocking only EGFR is likely to only impact a minority of patients. It is time for the laboratory and clinical researchers to work closely together to develop this treatment strategy, moving back and forth from clinical to laboratory to best understand how to block this network effectively enough to produce a broader antitumor effect. While multiple methods of targeting the EGFR pathway are under development, including the inhibition of downstream proteins, only two modalities have entered clinical trials in GI malignancies: small molecule inhibitors of the intracellular kinase domain of EGFR and antibodies designed to block the extracellular ligand-binding domain of EGFR. EGFR inhibitors are still experimental in every GI malignancy with the notable exception of cetuximab that is approved for second or third-line therapy of metastatic colorectal cancer, used either alone or in combination with irinotecan (Camptosar, Kalamazoo, Mich). Data on clinical applications of these agents in GI malignancies will be the focus of this paper.

Metalloprotease disintegrin-mediated ectodomain shedding of EGFR ligands promotes intestinal epithelial restitution

EGF receptor (EGFR) promotes intestinal epithelial restitution, an important early process in the reepithelialization of ulcers. During epithelial restitution, the mechanism of EGFR activation is not known. We evaluated the role of TNF-converting enzyme (TACE), a metalloprotease disintegrin that proteolytically processes plasma membrane-anchored EGFR ligand precursors into their mature active forms, in wound-induced EGFR activation and epithelial restitution. With the use of scrape-wounded rat intestinal epithelial-1 (RIE-1) cell monolayers to model epithelial ulceration and restitution, we observed the rapid wound-dependent release of EGFR ligands into culture medium. RIE-1 cells express TACE, and treatment with phorbol ester, an established TACE stimulus, triggered the extracellular release of an EGFR ligand, transforming growth factor-alpha. Blockade of TACE using TNF processing inhibitor (TAPI-1), a specific hydroxamate inhibitor of metalloprotease disintegrins, prevented release of EGFR ligands from wounded RIE-1 cell monolayers. The restitution of wounded RIE-1 cell monolayers was also dose-dependently inhibited by TAPI-1, establishing the role of metalloprotease disintegrins in this process. These results have established a mechanism of EGFR activation in wounded intestinal epithelium and show an important functional role for metalloprotease disintegrin-mediated ectodomain shedding during intestinal epithelial restitution. Therefore, activation of the TACE-EGFR system might promote the healing of intestinal tract ulcers in patients.

Epidermal Growth Factor Receptor as a Therapeutic Target for the Treatment of Colorectal Cancer

Colorectal carcinoma is the third most common malignancy worldwide. The use of currently available therapies results in only a modest impact on overall survival of patients with advanced-stage disease. New approaches for the treatment of colorectal cancer are urgently needed. The epidermal growth factor receptor (EGFR) is frequently dysregulated in colorectal carcinoma, and overexpression of the receptor confers a poor prognosis. Targeting the EGFR has become a rational approach for the treatment of colorectal carcinoma. Several strategies to inhibit the EGFR and its downstream signaling pathways are currently being investigated in preclinical and clinical studies, including monoclonal antibodies directed against the extracellular domain of the receptor and small-molecule inhibitors of its tyrosine kinase activity. Some of these drugs have already been tested in colorectal cancer and have shown preliminary evidence of antitumor efficacy. Important issues to elucidate in the future include the definition of the biologic context in which these drugs are more likely to be effective and the integration of the different agents in current therapeutic strategies for colorectal cancer. This article will provide a comprehensive review of the current available preclinical and clinical data on EGFR-targeted therapies in colorectal cancer.

Clinical implications of the EGF receptor/ligand system for tumor progression and survival in gastrointestinal carcinomas: evidence for new therapeutic options

The epidermal growth factor (EGF) receptor and its various ligands (EGF, TGF-alpha, amphiregulin, heparin-binding (HB)-EGF, heregulin, betacellulin) seem to be involved in the growth regulation of intestinal mucosa and might be related to the development and progression of gastrointestinal tumors. However, few quantitative data investigating the impact of tumor-EGF receptor levels in gastrointestinal carcinomas on tumor stage and prognosis are available. Therefore, EGF receptors were quantitatively determined in colorectal carcinomas in comparison to adjacent normal mucosa by 125I[EGF]-binding studies. EGFR capacity was increased in advanced invasive colorectal carcinomas (T1/2 vs. T3/4 tumors, p<0.001) and advanced UICC stages (UICC I vs. UICC II/III, p<0.001). These findings were confirmed with quantitative 125[I]EGF autoradiography performed on frozen tissue slides and analyzed by laser densitometry (p=0.020). EGF receptor analysis with immunohistochemistry with EGFR antibodies directed against the extracellular domain of the receptor was not correlated with tumor invasion or prognosis. mRNA-expression of EGFR ligands was investigated using semiquantitative RT-PCR amplification using specific primers. RT-PCR transcripts of EGFR ligands (EGF, TGF-alpha, HB-EGF, and amphiregulin) were detected in both carcinomas and normal mucosa, indicating that autocrine growth stimulation of colorectal carcinomas is mediated by coexpression of EGF receptor ligands and upregulation of EGF receptors. Survival of colorectal cancer patients with increased tumor EGF receptor levels was significantly reduced in comparison to patients with low/unchanged tumor EGF receptor levels (mean survival+/-SD, 36.2+/-4.0 vs. 46.8+/-4.3 months; p=0.017). Further studies investigating EGF receptor levels in gastric cancer patients have shown that increased tumor EGF receptor levels were associated with poor prognosis in gastric cancer patients with tumors localized distal from the cardia. Several specific EGF receptor tyrosine kinase inhibitors have recently entered clinical phase I-III studies, with promising antitumor effects in several tumors, including gastrointestinal cancer. Therefore, patients with invasive gastric or colorectal carcinomas might benefit from therapies specifically blocking EGFR-mediated signal transduction.

Epidermal growth factor receptor immunohistochemical reactivity in patients with American Joint Committee on Cancer Stage IV colon adenocarcinoma: implications for a standardized scoring system

BACKGROUND

An epidermal growth factor receptor (EGFR) immunohistochemical detection system currently is being developed. The current study attempts to address background EGFR reactivity issues before determining the optimum EGFR scoring system.

METHODS

Tissue sections from 102 patients with T3N1-2M1 colon adenocarcinoma were stained with a prototype EGFR detection system. The number of cases, location, percentage, and intensity of reactive cells (0+ [none] to 3+ [strong]) were scored and compared with the length of survival.

RESULTS

Approximately 75.5% of the adenocarcinoma cases had EGFR reactivity; 31.4% of the tumors had 3+ reactivity in 10-50% of the neoplastic cells and 3.9% had 3+ reactivity in > 50% of cells. Increased numbers of reactive cells per case predominantly resulted from increased 3+ reactivity. The mean percentage of 2+ (moderate) and 3+ reactive cells per case increased in the regions of deepest invasion. The mean percentage of 3+ reactivity per case was significantly greater in the deepest tumor region compared with the superficial region (16.9% vs. 7.9%; P = 0.004). EGFR reactivity in metastases appeared to have the strongest correlation with reactivity in the deep regions of colon adenocarcinoma. An increasing percentage of 2+ and 3+ or 3+ only reactivity in the deep region was found to have the strongest correlation with decreased survival (P = 0.0252).

CONCLUSIONS

EGFR reactivity of 2+ and 3+ may provide a framework for a scoring system. It may be important to evaluate EGFR reactivity in the deepest region of tumor invasion because this region appears to contain the largest percentage of 3+ reactive cells and appears to have the strongest correlation with survival length and EGFR reactivity in lymph node and liver metastases.

Epidermal growth factor receptor immunohistochemical reactivity in patients with American Joint Committee on Cancer Stage IV colon adenocarcinoma: implications for a standardized scoring system

BACKGROUND

An epidermal growth factor receptor (EGFR) immunohistochemical detection system currently is being developed. The current study attempts to address background EGFR reactivity issues before determining the optimum EGFR scoring system.

METHODS

Tissue sections from 102 patients with T3N1-2M1 colon adenocarcinoma were stained with a prototype EGFR detection system. The number of cases, location, percentage, and intensity of reactive cells (0+ [none] to 3+ [strong]) were scored and compared with the length of survival.

RESULTS

Approximately 75.5% of the adenocarcinoma cases had EGFR reactivity; 31.4% of the tumors had 3+ reactivity in 10-50% of the neoplastic cells and 3.9% had 3+ reactivity in > 50% of cells. Increased numbers of reactive cells per case predominantly resulted from increased 3+ reactivity. The mean percentage of 2+ (moderate) and 3+ reactive cells per case increased in the regions of deepest invasion. The mean percentage of 3+ reactivity per case was significantly greater in the deepest tumor region compared with the superficial region (16.9% vs. 7.9%; P = 0.004). EGFR reactivity in metastases appeared to have the strongest correlation with reactivity in the deep regions of colon adenocarcinoma. An increasing percentage of 2+ and 3+ or 3+ only reactivity in the deep region was found to have the strongest correlation with decreased survival (P = 0.0252).

CONCLUSIONS

EGFR reactivity of 2+ and 3+ may provide a framework for a scoring system. It may be important to evaluate EGFR reactivity in the deepest region of tumor invasion because this region appears to contain the largest percentage of 3+ reactive cells and appears to have the strongest correlation with survival length and EGFR reactivity in lymph node and liver metastases.

Electrocautery snare resection stimulates cellular proliferation of residual colorectal tumor: an increasing gene expression related to tumor growth

PURPOSE

Recently, endoscopic mucosal resection has been performed commonly for colorectal tumors. However, incomplete endoscopic mucosal resection produces a residual tumor that grows rapidly. The aim of this study was to clarify the characteristics of the residual tumor using the nude mouse model.

METHODS

Human colon cancer cells (colo201 or colo320DM) were implanted subcutaneous into nude mice. We then removed more than one-half of the tumor with an electrocautery snare or a surgical knife, and compared the tumor growth rate with that of control tumors. Before and after resection, we examined the Ki-67 labeling index of the tumors with an immunohistochemical assay and mRNA expression for epidermal growth factor receptor, vascular endothelial growth factor, and transforming growth factor alpha.

RESULTS

Residual tumors showed a higher growth rate in tumor volume than control tumors using both methods (electrocautery snare and surgical knife). Colo201 groups showed a higher total volume change per day than colo320DM groups after resection. Furthermore, these tumors also showed a higher Ki-7 labeling index, and a stronger epidermal growth factor receptor and transforming growth factor alpha mRNA expression than primary and control tumors in the colo201 implanted groups. There was no significant difference in vascular endothelial growth factor mRNA expression between groups implanted with colo201 or colo320DM.

CONCLUSION

Our results suggest that residual tumors caused by incomplete endoscopic mucosal resection may have a higher growth potential than the tumors before resection.

Cell surface molecules and their prognostic values in assessing colorectal carcinomas

OBJECTIVE

Carcinomas of the colon and rectum are the third leading cause of cancer-related deaths. Although advances in the surgical treatment of primary colorectal cancers have lead to improvements in patient survival at early tumor stages, treatment of more progressive cancers has not resulted in dramatic improvements in patient survival. However, the selection of patient subgroups based on their prognosis and other characteristics could result in improved outcomes from adjuvant therapies in patients with Dukes B and C carcinomas.

METHODS

The authors reviewed the available data on the value of cell surface molecules in assessing the prognosis of colorectal carcinomas, paying specific attention to the evaluation of statistical analysis and multivariate procedures.

RESULTS

Cell surface molecules have been identified on colorectal carcinoma cells whose expression appears to be related to malignant transformation, tumor progression, or patient prognosis. Among these cell surface molecules, various cell adhesion molecules, growth factor receptors, proteinases, and their receptors and inhibitors have been identified as potentially useful prognostic markers.

CONCLUSIONS

Although data exist on the prognostic values of certain cell surface markers, the use of multivariate analysis for the identification of valuable prognostic factors remains uncommon. Using reproducible and standardized multivariate analysis procedures, new tumor markers should be carefully examined for their biologic and prognostic relevance before being considered as potentially useful in the management of colorectal cancers.

Clinical relevance of transforming growth factor alpha, epidermal growth factor receptor, p53, and Ki67 in colorectal liver metastases and corresponding primary tumors

To determine whether the expression of transforming growth factor alpha (TGF-alpha), its receptor (epidermal growth factor receptor [EGFr]), p53 nuclear protein, and proliferation influences prognosis of patients with liver metastases, a study was performed in 45 liver metastases and 33 corresponding primary colorectal carcinomas in patients referred for liver surgery. The expression of TGF-alpha, EGFr, p53 nuclear protein, and proliferation rate was correlated with clinicopathological characteristics and survival after partial liver resection. In liver metastases, TGF-alpha expression was low in 42%, intermediate in 35%, and high in 23%. TGF-alpha expression was higher in liver metastases derived from lymph node-positive primary carcinomas, in synchronous and in irresectable liver metastases compared with those derived from lymph node-negative primary carcinomas, metachronous, and resectable liver metastases. Nuclear p53 expression was found in 83% of primary tumors and 71% of liver metastases. p53 expression did not correlate with the various clinicopathological characteristics. Ki67 expression was not associated with clinicopathological characteristics in primary and metastatic tumors. In the 38 patients in whom a partial liver resection was performed, median survival was 25 months in patients with a higher TGF-alpha expression in the metastasis than in the primary tumor and 60 months in patients with comparable or lower TGF-alpha expression in the metastasis than in the primary tumor (P = .036). Median survival after liver resection was 21 months in patients with p53-negative liver metastases and 58 months in patients with p53-positive metastases (P = .043). By multivariate analysis, p53 and EGFr expression on liver metastases were the best predictors of disease-free survival after partial liver resection, with relative risks of 2.38 and 3.33, respectively. In patients with colorectal liver metastases, referred for liver surgery, a higher TGF-alpha expression is associated with unfavorable tumor characteristics, whereas p53 and absence of EGFr expression is associated with a better survival after partial liver resection.

Role of epidermal growth factor (EGF) in oesophageal mucosal integrity

Oesophageal mucosa has well established protective mechanisms, which operate within pre-epithelial, epithelial and post-epithelial compartments. Since refluxed acid and pepsin always act from the luminal side of the mucosa, protective factors like EGF, operating as a part of pre-epithelial defence, are thought to be pivotal in the maintenance of the integrity of the oesophageal mucosa. The significant contribution of salivary EGF to the quality of the oesophageal mucosal barrier has been demonstrated in an experimental setting and in a clinical scenario. Patients with low salivary EGF levels are predisposed to severe oesophageal damage if they develop gastro-oesophageal reflux and are a high-risk group for development of Barrett's oesophagus. Not only the salivary glands but also the human oesophagus has a profound ability to elaborate and release EGF. Some changes in luminal release of EGF during oesophageal mucosal exposure to intraluminal damaging factors imply its role in the oesophageal protective mechanisms. To exert biological effects within the oesophageal mucosal compartment, EGF requires binding to the ligand-binding domain of its receptor. This process results in receptor dimerisation, autophosphorylation and activation of intracellular signal transduction pathways. EGF receptors are localised on the basolateral and luminal aspect of the mucosal cells playing an important role in fast regeneration of oesophageal epithelium through the high mitotic activity of its proliferative zone. An increase in the rate of salivary EGF secretion during masticatory stimulation suggests its potential therapeutic benefit in the treatment of patients with damaged oesophageal mucosa.

Clonal origin of trisomy for chromosome 7 in the epithelial compartment of colon neoplasia

In this study, we demonstrated the clonal origin of trisomy for chromosome 7 in epithelial cells of colon neoplasia. By using the double-target fluorescence in situ hybridization (FISH) technique in frozen tissue sections that were also immunostained for keratin and vimentin, ratio analysis of FISH signals for chromosomes 7 and 17 could be performed in epithelial (cytokeratin-positive) or stromal (vimentin-positive) areas. The data demonstrated that trisomy for chromosome 7 is found exclusively in the epithelial compartments and not in the stroma of colon adenocarcinoma. We then demonstrated the occurrence of trisomy for chromosome 7 in the different types of epithelial neoplastic cells, i.e., columnar and goblet cells, which were isolated from frozen tissue sections by mechanical disaggregation of colon tissue and mild lysis of the cells while protease activity was inhibited. In these cell suspensions, the columnar cells were detected with an antibody to villin, and the goblet cells were stained for mucin, whereas all cells were subsequently subjected to FISH for chromosome 7. For analysis of neuroendocrine cells, which are present in a very low frequency in colon neoplasia, frozen tissue sections that were immunostained for Chromogranin A could be used. Individual neuroendocrine cells could be distinguished in these thin frozen tissue sections. The presence of trisomy for chromosome 7 in all three different epithelial cell types strengthens our suggestion that this chromosomal aberration is found in the epithelial stem cell compartment of colon neoplasia.

Growth factor mRNA expression in normal colorectal mucosa and in uninvolved mucosa from ulcerative colitis patients

This study was carried out to investigate the expression of various growth factors (GFs) involved in mucosal healing and thereby to clarify whether there are potential differences in the expression of GFs between normal colonic mucosa and the uninvolved mucosa of ulcerative colitis (UC). GF mRNA was investigated by reverse transcription polymerase chain reaction in colorectal biopsies from 20 normal controls and 15 UC patients. The positive rates (%) for mRNA expression for normal/UC were: epidermal growth factor (EGF) 65/53, transforming growth factor (TGF)-alpha 100/87, TGF-beta 1 60/33, insulin like growth factor-I 45/33, platelet-derived growth factor-A 55/67, basic fibroblast growth factor 0/0, hepatocyte growth factor (HGF) 50/53, EGF receptor 20/27, erb-B2 75/73, and HGF receptor (c-MET) 55/67. Semiquantitation of mRNA showed significantly lower expression of TGF-beta 1 (P < 0.05) in UC. Differences in expression and mRNA levels were not statistically significant for any other GFs. Our results indicate that mucosa in chronic persistent UC has a low basal expression of TGF-beta 1 mRNA, and, since TGF-beta 1 is a multifunctional GF that plays important roles in regulating repair and regeneration following tissue injury, this low expression may be partially responsible for the intractability of the disease.

The relationship between mast cell infiltration and the expression of PCNA and EGFr in experimental hepatocellular carcinoma of liver and squamous cell carcinoma of stomach in rats

The expression of PCNA and EGFr in chemically induced hepatocellular carcinoma of liver and squamous cell carcinoma of stomach in rats were immunohistochemically observed. The results showed that the carcinoma cells of both tumors revealed a positive immunreaction to PCNA and EGFr. The histochemical observation of mast cell (MC) in both tumor tissues showed that the amount of MC in the surroundings of tumor cell nests was markedly different. According to the amount of the surrounding MCs the tumor cell nests could be divided into two groups: Group A with abundant MC infiltration and Group B with only scarce or without MC infiltration. The PCNA-positive cells in the tumor cell nests of both groups were calculated respectively. The results revealed that the amount of PCNA-positive cells in the group B was markedly more than that in the group A. The numerical ratio between two groups was 3:1 in the liver carcinoma and 2:1 in the stomach carcinoma approximately. An overexpression of EGFr was observed in tumor tissues of both groups, but there was also a marked difference in the amount of positively expressed cells and in the intensity of their staining reaction between both groups. The positively expressed cells in group B were much more and their staining intensity was much stronger than those in group A. According to the above mentioned results of observation, the expression state of both factors (PCNA and EGFr) was basically identical, suggesting that the MC may possess some inhibitory effect upon the growth rate of tumor cells of the experimental hepatocellular carcinoma of liver and the squamous cell carcinoma of stomach in rats.

Expression of epidermal growth factor receptor messenger RNA in human colorectal carcinomas assessed by non-radioactive in-situ hybridization

No consensus as to the involvement of the epidermal growth factor receptor (EGF-R) in colorectal carcinomas has yet been attained, although they are assumed to play a role in the metastasis to lymph nodes and recurrence of breast carcinoma and bladder carcinoma invasion. Knowing that Dukes' classification of colorectal carcinoma is closely related to prognosis, we examined whether there is a correlation between Dukes' classification and the expression of EGF-R in colorectal carcinoma. If there is a positive correlation, the involvement of EGF-R in the processes may be assumed and the expression of EGF-R may be used as a marker of their prognosis. To this end, the expression of EGF-R mRNA and protein by non-radioactive in-situ hybridization and immunohistochemistry, respectively, were determined on histological preparations of formalin-fixed paraffin-embedded colorectal surgical specimens. In 30 cases of colorectal carcinoma examined, mRNA and/or protein was detected in 33% (two of six) of Dukes' A, in 40% (four of 10) of Dukes' B, in 36% (four of 11) of Dukes' C, in 33% (one of three) of Dukes' D and in 0% of normal colon epithelial cells. Thus, there was no positive correlation between the Dukes' classification and the expression of EGF-R. It is concluded that the expression of EGF-R in colorectal carcinoma is not a promising marker of prognosis. However, the role of EGF-R in EGF-R positive tumours remains to be examined.

Subcutaneous but not intraluminal epidermal growth factor stimulates colonic growth in normal adult rats

Epidermal growth factor (EGF) was administered by chronic subcutaneous or intracolonic infusion into normal adult rats to determine the effect on colonic growth. Subcutaneous infusion of 200 micrograms EGF/kg/day for 7 days increased the cross-sectional mass and protein content of the muscularis and mucosal layers of the proximal colon, with the distal colon showing less response. In the mucosa, subcutaneous EGF induced proportional increments in the number of cells per crypt, and in the number of cells positively labelled for PCNA, while maintaining a normal crypt growth fraction. In contrast, an 8-fold higher dose of EGF administered intraluminally had no effect on colonic mucosal or muscularis growth. This lack of bioactivity was unlikely to reflect rapid luminal degradation as radiolabelled EGF remained stable in the colonic lumen for at least 4 h. The results demonstrate that the normal adult colon is responsive to subcutaneously delivered EGF, particularly the proximal colon, whereas EGF may not be active on the normal colon when presented from the luminal direction.