Combination of EGFR gene copy number and protein expression predicts outcome for advanced non-small-cell lung cancer patients treated with gefitinib.

BACKGROUND: Biological markers for optimal selection of patient to epidermal growth factor receptor (EGFR)-targeted therapies are not established in advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: EGFR/HER2 gene copy number by FISH, EGFR protein and pAKT expression by immunohistochemistry (IHC) and EGFR and KRAS mutations were tested in 204 gefitinib-treated NSCLC patients. RESULTS: Increased EGFR and HER2 gene copy number (FISH+), EGFR protein overexpression (IHC+), EGFR mutations and pAKT overexpression were all associated with significantly higher response rates (33%, 29%, 22%, 39% and 20% respectively). EGFR FISH+ (32%) and IHC+ (61%) correlated with improved survival, while EGFR mutations (27%), KRAS mutations (26%) and pAKT expression (69%) did not. In multivariate survival analysis EGFR FISH and IHC were independent predictive markers. EGFR FISH+/IHC+ patients (23%) had a median survival of 21 months versus 6 months for double-negative patients (30%). CONCLUSION: Combination of EGFR FISH and IHC is effective predictor for benefit from gefitinib. Patients with double-negative results are unlikely to benefit in western NSCLC populations.     

EGFR High Copy Number Together With High EGFR Protein Expression Predicts Improved Outcome for Cetuximab-based Therapy in Squamous Cell Lung Cancer: Analysis From SWOG S0819, a Phase III Trial of Chemotherapy With or Without Cetuximab in Advanced NSCLC

BackgroundThe phase III S0819 trial investigated addition of cetuximab to first-line chemotherapy (CT) in NSCLC. Subgroup analyses suggested an OS benefit among patients with EGFR copy number gain in squamous cell carcinomas (SCC), (HR = 0.58 [0.39-0.86], P = .0071). A more detailed model based on EGFR FISH, EGFR IHC and KRAS mutation status was evaluated to yield a more precise predictive paradigm of cetuximab-based therapy in advanced NSCLC.MethodsFISH was performed using the Colorado Scoring Criteria; H-Score was used to quantify EGFR IHC expression (cut-off ≥ 200). A Cox model was used to assess treatment effects for OS and PFS within biomarker and clinical subgroups. KRAS mutation was analyzed using Therascreen. The false discovery rate controlled for multiple comparisons. S0819 ClinicalTrials.gov Identifier: NCT00946712.ResultsOf 1,313 eligible patients, assay results were obtained for FISH on 976 patients (41% positive), for IHC on 945 patients (31% positive), and KRAS mutation status on 627 patients (26% positive). In SCC patients, OS was significantly improved with addition of cetuximab when both EGFR FISH and EGFR IHC were positive (N = 58), (OS HR: 0.32 [95% CI 0.18-0.59]; P = .0002, q = 0.08), median 12.6 versus 4.6 months. The results were independent of KRAS mutation status. In Non-SCC, no predictive value of EGFR IHC, EGFR FISH status and/or KRAS status was seen.ConclusionsIn NSCLC SCC, a combination index of EGFR FISH plus EGFR IHC results was associated with improved OS when cetuximab was added to CT, representing a potential predictive molecular paradigm for patients suitable for EGFR-antibody therapy.     

HER-2/neu gene amplification by fluorescence in situ hybridization allows risk-group assessment in node-negative breast cancer

In a collective of 112 node-negative breast cancer patients, we compared the prognostic impact of HER-2/neu gene amplification (AMP) determined by fluorescence in situ hybridization (FISH) and HER-2/neu protein overexpression (EXP) measured by immunohistochemistry (IHC) with traditional prognostic factors (tumor size, grade, steroid hormone receptor status, menopausal status) and tumor invasion markers uPA (urokinase-type plasminogen activator) and its inhibitor PAI-1 determined by enzyme immunoassay (ELISA). Median follow-up in patients still alive at time of analysis was 7 years. Automated FISH and IHC were performed on parallel-cut formalin-fixed paraffin-embedded tissue sections. HER-2/neu AMP was detected by FISH in 31% and HER-2/neu EXP was measured by IHC in 41% of the cases. In 13% of the tumors, both AMP and EXP were found. FISH and IHC results were concordant in 56% of all analyzed cases. In univariate analysis, HER-2/neu AMP significantly predicted both disease-free (DFS) and overall survival (OS). HER-2/neu EXP was significant for OS, only. In multivariate analysis of all analyzed prognostic factors, HER-2/neu AMP was the only independent predictive factor for both DFS and OS. CART analysis revealed that HER-2/neu AMP together with the combination uPA/PAI-1 allowed optimal risk-group assessment after a 7-year median follow-up: patients with low levels of both uPA and PAI-1 and no HER-2/neu AMP had a significantly lower relapse rate (4.6%) than the remaining patients (32%). In conclusion, HER-2/neu gene AMP determined by FISH allowed a more accurate risk-group assessment than HER-2/neu protein EXP measured by IHC. Combining the HER-2/neu gene status measured by FISH with levels of tumor invasion markers uPA and PAI-1 improves clinically relevant risk-group assessment. In addition to its prognostic strength, the significant impact of HER-2/neu AMP on OS may reflect its ability to predict resistance to systemic therapy.     

Is there a relationship between c-erbB-1 and c-erbB-2 amplification and protein overexpression in NSCLC?

In order to analyse the genetic abnormalities and protein expression of c-erbB-1 and -2, we have performed fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC) in resected non-small cell lung carcinoma (NSCLC). By IHC (106 patients), 11% of the patients were positive both for c-erbB-1 and -2 protein expression and 47% negative for both proteins. FISH (69 patients) showed a balanced disomy for both c-erbB-1 and -2 in 38%, all other cases had genetic abnormalities in at least one of both genes. c-erbB-2 gene was amplified in less than 10% of the tumours and c-erbB-1 gene was never amplified. c-erbB-2 protein overexpression was observed in only three out of the six cases showing c-erbB-2 amplification. The negative predictive value (NPV) of IHC for gene abnormalities was high for both markers. Median survival time (MST) was respectively of 76 and 174 weeks for patients with or without c-erbB-2 overexpression. Patients with c-erbB-2 amplification had a shorter survival: 125 weeks versus 165 weeks. MST was respectively of 109 and 196 weeks for patients with or without EGFR overexpression and patients with EGFR gene abnormalities had also a shorter survival with MST 136 weeks versus 189 weeks. These differences were not significant. In conclusion, if the majority of NSCLC showed genetic abnormalities in the c-erbB-1 and/or c-erbB-2 gene receptor, amplification could be observed only in a few tumours and was not strictly correlated with protein expression. Finally, survival of patients expressing EGFR and/or c-erbB-2 was slightly shorter.     

非小细胞肺癌EGFR荧光原位杂交与免疫组化检测的比较

目的探讨荧光原位杂交（FISH）技术和免疫组化（IHC）法检测石蜡标本非小细胞肺癌（NSCLC）EGFR基因扩增及蛋白表达水平的差异性。方法采用FISH和IHC分别检测27例NSCLC患者石蜡标本EGFR基因和蛋白表达,对2种方法的检测结果进行对比分析。结果 14例IHC法EGFR表达（3＋）的标本中有9例FISH显示阳性（64.29%）,其中5例为EGFR基因高多体性扩增（55.56%）,4例为EGFR基因扩增（44.44%）;6例IHC（2＋）的标本中仅1例为高多体性扩增（16.67%）;2例IHC（1＋）及5例IHC（-）标本均无EGFR基因扩增。结论 IHC法初筛（3＋）、（2＋）的标本与FISH检测的符合率较低,提示对IHC检测EGFR表达为（3＋）及（2＋）并选择靶向药物治疗的病例,应采用FISH法对EGFR基因表达作进一步检测。     

Epidermal growth factor receptor (EGFR) in salivary gland carcinomas: Potentials as therapeutic target

AimsEpidermal growth factor (EGFR) is involved in angiogenesis, cell differentiation, proliferation and progression of many cancers and is an important therapy target in lung and colorectal cancer. To determine the potential applicability of EGFR targeted therapies, EGFR status of over 800 salivary gland tumors of different entities were analyzed on DNA and protein level by FISH and IHC.Materials and methodsA tissue microarray was constructed from 721 carcinomas and 205 adenomas of the salivary gland. EGFR expression and EGFR gene copy number was assessed by means of immunohistochemistry and fluorescence in situ hybridization (FISH). EGFR mutation analysis of exon 19 and 21 was performed in a subset of 107 carcinomas.ResultsPositive immunohistochemical staining (definition?) for EGFR was shown in 324 of 663 (48.9%) salivary gland carcinomas. The frequency was dependent on the tumor entity and ranged from 17.9% (30 of 168 cases) positive immunostaining in acinic cell adenocarcinomas to 85.7% (42 of 49 cases) in Warthin tumors. No EGFR amplification was found by FISH. EGFR mutation analysis of Exon 19 and 21 in 107 salivary gland carcinomas revealed mutations in two acinic cell adenocarcinomas .ConclusionEGFR protein expression is common in salivary gland tumors but is not associated with gene amplification. Activating mutations of EGFR are rare. Nonetheless, selected cases of patients with salivary gland carcinomas might potentially benefit of anti-EGFR therapy.     

HER2 status in non-small cell lung cancer: results from patient screening for enrollment to a phase II study of herceptin.

PURPOSE: For the first time a large number (563) of non-small cell lung cancer (NSCLC) samples was used to compare three different technologies for the assessment of HER2 status. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) were used for tumor tissue samples, and ELISA for serum samples. The results were compared with other tumor entities, mainly breast. EXPERIMENTAL DESIGN: Samples (563) from patients suffering from primary advanced or metastatic NSCLC were evaluated. RESULTS: HER2 overexpression was demonstrated using IHC in 20% (83 of 410) of the specimens, whereas 2% (7 of 378) were positive by FISH and 6% (31 of 511) showed elevated serum HER2 levels (>15 ng/ml) by ELISA. Sixty-six specimens were positive by IHC only and 13 by ELISA only, whereas none of the specimens was positive only by FISH. Concordance between all of the techniques was seen for only 3 specimens. Of 7 IHC 3+ specimens, 4 showed gene amplification by FISH, and 3 were positive by ELISA (>15 ng/ml), whereas of 76 IHC 2+ cases only 2 were amplified by FISH, and 4 were positive by ELISA. HER2 positivity by at least one of the three techniques was most common in adenocarcinomas, at 29% (42 of 143). CONCLUSION: Gene amplification and HER2 protein overexpression at the 3+ level appear to be uncommon in NSCLC. The concordance between FISH and IHC 3+ disease was good in this study, in addition, ELISA would have detected several patients without IHC/FISH-positive disease.     

Biomarkers for prediction of sensitivity to EGFR inhibitors in non-small cell lung cancer

PURPOSE OF REVIEW: Epidermal growth factor receptor (EGFR) Inhibitors have shown promising results in patients with advanced non-small cell lung cancers (NSCLC) who previously have failed on chemotherapy. Objective response is achieved in 10 to 28% of the patients, and about 30% will achieve stable disease. A major problem is how to select the patients, who will benefit from treatment, and who will not. RECENT FINDINGS: The predictive role of EGFR protein expression assessed by IHC is still debated. Specific EGFR gene mutations have been identified associated with response to gefitinib (Iressa(R)), but seem not to be associated with stable disease. No studies have yet demonstrated any association between EGFR gene mutations and survival. In this review we describe other marker studies, which are associated with sensitivity to EGFR inhibitors. Increased EGFR gene copy number based on FISH analysis is demonstrated to be a good predictive marker for response, stable disease, time to progression, and survival. SUMMARY: EGFR/FISH seems today to be the best predictive marker for clinical benefit from EGFR inhibitors in NSCLC. Prospective large scale clinical studies must identify the most optimal paradigm for selection of patients.     

Controversial evaluation of EGFR protein and gene status in predicting response to anti-EGFR monoclonal antibodies in metastatic colorectal cancer: a case report and review of the literature

Clinical studies showed that only 10% of patients with metastatic colorectal cancer (mCRC) respond to treatment with the anti-epidermal growth factor receptor (EGFR) monoclonal antibodies panitumumab or cetuximab, regardless of the line of treatment. The current tool used to select patients, i.e. immunohistochemistry (IHC) evaluation of EGFR expression by EGFR pharmDx™ Kit, is not reliable in predicting response. Retrospective analyses of factors such as increased EGFR gene copy number and KRAS and/or BRAF mutations showed that such molecular changes could affect clinical benefit from anti-EGFR monoclonal antibodies. We report here the case of a 66-year-old man with chemorefractory mCRC, considered not eligible to salvage treatment with the anti-EGFR monoclonal antibody cetuximab and irinotecan because the primary adenocarcinoma of the rectum was found not expressing EGFR protein by IHC. However, FISH analysis of EGFR gene copy number and evaluation of KRAS and/or BRAF specific mutations by gene sequencing showed characteristics associated with favourable clinical outcome to anti-EGFR therapy. Based on the EGFR protein expression by IHC in a liver metastasis, the patient was then treated with cetuximab plus irinotecan, obtaining symptoms improvement and a dramatic objective tumor response in all sites of disease, lasting 4.2 months. We also discuss literature findings about the role of different biological characteristics in predicting clinical benefit from anti-EGFR therapy in patients with mCRC. Supported by research grants from Associazione Italiana Ricerca Cancro (AIRC) and Oncologia Ca’ Granda ONLUS Fondazione.     

Agreement between chromogenic in situ hybridisation (CISH) and FISH in the determination of HER2 status in breast cancer

Determination of the HER2/neu (HER2) status in breast carcinoma has become necessary for the selection of breast cancer patients for trastuzumab therapy. Amplification of the gene analysed by fluorescence in situ hybridisation (FISH) or overexpression of the protein determined by immunohistochemistry (IHC) are the two major methods to establish this status. A strong correlation has been previously demonstrated between these two methods. However, FISH is not always feasible in routine practice and weakly positive IHC tumours (2+) do not always correspond to a gene amplification. Our study was performed in order to evaluate the contribution of chromogenic in situ hybridisation (CISH), which enables detection of the gene copies through an immunoperoxidase reaction. CISH was performed in 79 breast carcinomas for which the HER2 status was previously determined by IHC and FISH. The results of IHC, FISH and CISH were compared for each tumour. CISH procedures were successful in 95% of our cases. Whatever the IHC results, we found a very good concordance (96%) between CISH and FISH. Our study confirms that CISH may be an alternative to FISH for the determination of the gene amplification status in 2+ tumours. Our results allow us to think that, in many laboratories, CISH may also be an excellent method to calibrate the IHC procedures or, as a quality control test, to check regularly that the IHC signal is in agreement with the gene status.     

Assessment of Epidermal Growth Factor Receptor (EGFR) signaling in paired colorectal cancer and normal colon tissue samples using computer-aided immunohistochemical analysis

The Epidermal Growth Factor Receptor (EGFR) plays a role in multiple tumor cell processes and is targeted by several anticancer therapies. Although EGFR mutations may determine tumor susceptibility in a small proportion of patients, knowledge of the EGFR signaling pathway status in tumors may help guide further drug development and hypothesis-driven combination studies. We aimed to validate and apply a novel computer-aided immunohistochemical (IHC) technique to characterize the status of EGFR signaling in matched colorectal tumor and normal colon tissue samples. Tissue Microarrays (TMA)were made from both cancerous and normal colorectal tissue in 18 patients and stained with antibodies against EGFR, phospho-EGFR (pEGFR), Akt, pAkt, MAPK, and pMAPK. TMA's were quantitatively scored using the Automated Cellular Imaging System (ACIS II, Chromavision, Inc). ACIS was compared against cell line Western blotting, ELISA, and visual scoring (0-3+) by a pathologist. We found that ACIS analysis was highly reproducible and results were well correlated with other techniques. A post-scan "image microdissection" technique of analyzing heterogeneous human samples showed good correlation between paired human samples [Pearson correlation for tumors, 0.922 (p < .001)]. Cancer samples had markedly higher staining of pEGFR, Akt, pAkt, MAPK, and pMAPK. We conclude that ACIS IHC of human tissue samples is quantitative, reproducible, and correlates with Western blots and ELISA in cell line pellets as well as pathologist's scores of human samples. Colorectal tumors show higher staining of pEGFR and downstream effectors compared to matched normal colorectal tissues.     

Correlation between topoisomerase-IIalpha gene amplification and protein expression in HER-2 amplified breast cancer

Topoisomerase-IIalpha (topo-II) is a molecular target for topo-II inhibitors, which makes it a potential predictive marker of responsiveness to these agents. We aim to correlate topo-II gene and protein status on 103 HER-2 amplified breast cancer samples. Paraffin-embedded blocks were screened by FISH for topo-II gene amplification (topo-II: CEP17 ratio >/=1.5; triple probe by Vysis inc.) and analyzed by IHC for topo-II protein expression (continuous variable; clone KiS1) and Ki-67 (positive if >25% of stained cells; clone MIB-1). Topo-II gene amplification was observed in 36.9% (38/103) of the HER-2 amplified study population. HER-2 amplification level (e.g. copy number) was not shown to be predictive for topo-II amplification. The median percentage of topo-II positively stained cells by IHC for topo-II non-amplified and amplified cases were 5% and 10%, respectively. A weak but significant correlation was observed between topo-II gene amplification level and percentage of positively stained cells (Spearman's ranks correlation coefficient of 0.23, p=0.02), the observed correlation being higher in patients with positive staining for Ki-67. Contrary to HER-2, where gene amplification is almost always correlated with protein overexpression in breast cancer, topo-II gene amplification apparently does not always lead to protein overexpression, at least when the latter is evaluated by IHC. Other factors, specifically the tumor proliferation status, may interfere with the topo-II protein status. Although the great majority of topo-II gene aberrations occur in HER-2 positive tumors, the level of HER-2 amplification does not predict for topo-II amplification.     

Prognostic significance of epidermal growth factor receptor in laryngeal squamous cell carcinoma.

Epidermal growth factor receptor (EGFR) content was determined by a radioligand receptor assay in 140 primary laryngeal squamous cell carcinomas (median value of 8.4 fmol mg-1 protein, range 0-169.9 fmol mg-1 protein). Cox univariate regression analysis using EGFR as a continuous variable showed that EGFR levels are directly associated with the risk of death (chi 2 = 14.56, P-value = 0.0001) and relapse (chi 2 = 7.77, P-value = 0.0053). A significant relationship between EGFR status and survival was observed at the different arbitrary cut-off values chosen (8, 16 and 20 fmol mg-1 protein). The cut-off value of 20 fmol mg-1 protein was the best prognostic discriminator. In fact, the 5 year survival was 81% for patients with EGFR- tumours compared with 25% for patients with EGFR+ tumours (P < 0.0001). The 5 year relapse-free survival was 77% for patients with EGFR- tumours compared with 24% for patients with EGFR+ tumours (P < 0.010). When clinicopathological parameters and EGFR status were examined in the multivariate analysis, T classification and EGFR status retained an independent prognostic value. In this study we demonstrated that high EGFR levels single out patients with poor prognosis in laryngeal cancer.     

ESR1 gene status correlates with estrogen receptor protein levels measured by ligand binding assay and immunohistochemistry

The Estrogen Receptor (ER) is an established predictive marker for the selection of adjuvant endocrine treatment in early breast cancer. During the 1990s Immunohistochemistry (IHC) replaced cytosol based assays for determination of ER status. This study examined the association between ER protein level determined by two different methods and ESR1 gene copy number. From 289 primary high-risk breast cancer patients, randomized in the Danish Breast Cancer Cooperative Group (DBCG) 77C trial, results from cytosolic ER levels were available from ligand binding assays. Archival tumor tissue was retrieved from 257 patients. ESR1/CEN-6 ratio was analyzed successfully by Fluorescence In Situ Hybridization (FISH) in 220 (86%) patients. ESR1 amplification (ESR1/CEN-6 ≥ 2.00) was observed in 23% of the patients and ESR1 deletion (ESR1/CEN-6 < 0.80) was observed in 32%. Further, we identified ESR1 gain (ratio ESR1/CEN-6 from 1.30 to 1.99) in 19% of the patients. A positive correlation of ESR1 FISH with both ER-cytosol and ER IHC was found (p < 0.0001). Amplification and gain of the ESR1 gene are associated with higher ER protein content measured by ligand binding assay and a more intense nuclear staining by IHC compared to tumors with normal ESR1 gene status. Major variations in ER measured by ligand binding assay and IHC are observed within all ESR1 copy number subgroups and other mechanisms than gene copy number seem to contribute to the ER protein content in the tumors.     

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.     

Thymidylate synthase genotyping is more predictive for therapy response than immunohistochemistry in patients with colon cancer

Thymidylate synthase (TS) is a potentially valuable marker for therapy response since it is the molecular target of 5-fluorouracil (5-FU). TS can be analyzed at the DNA (gene polymorphisms and amplification) and protein level (immunohistochemistry). This study investigated the predictive role of TS at the DNA and protein levels in patients with N(+) colon cancer (n = 38). Tumor and normal tissues were genotyped using PCR for variable number of tandem repeats (VNTR), a single nucleotide polymorphism (SNP) in the 3R allele and a 6 bp deletion (1494del6) in the TS gene. Tumor tissues were additionally analyzed for loss of heterozygosity (VNTR polymorphism). A newly developed real time PCR assay was used to detect the presence of TS gene amplifications in tumor tissues. VNTR analysis in normal tissue was significantly associated with distant tumor recurrence (8% for 2R/2R vs. 52% for patients carrying a 3R allele, p = 0.038) and cancer-specific survival (p = 0.021). IHC was not found to be significantly associated with patients' outcome. No correlations between TS gene polymorphisms and IHC were found. However, TS gene amplification was correlated with a strong IHC staining intensity. In conclusion, this study indicates that DNA based analysis is more predictive for patients' outcome than TS IHC.     

Clinical usefulness of EGFR gene copy number as a predictive marker in colorectal cancer patients treated with cetuximab: a fluorescent in situ hybridization study

PURPOSE: To evaluate the usefulness and the pitfalls inherent to the assessment of the epidermal growth factor receptor (EGFR) gene copy number (GCN) by fluorescence in situ hybridization (FISH) for outcome prediction to cetuximab in metastatic colorectal cancer. The value of testing KRAS mutation status, in addition to EGFR GCN, was also explored. EXPERIMENTAL DESIGN: FISH analysis of 87 metastatic colorectal cancer patients treated with cetuximab was done, recording individual GCN per cell and using different samples per tumor. Performances of published cutoff points and different summaries of EGFR GCN distribution were assessed for response prediction. RESULTS: In our data set, two published cutoff points performed less well than in their training set, yielding positive predictive values and negative predictive values between 40.0% and 48.3% and between 81.0% and 86.5%, respectively. Among summaries of GCN distribution explored, mean and right-tailed distribution of GCN yielded the highest performances. A mean EGFR GCN > or = 2.83 provided an area under the curve of 0.71. Important heterogeneity of repeated measures of mean EGFR GCN was observed within tumors (intraclass correlation, 0.61; within-class SD, 0.40), leading to potential misclassifications of FISH status in 7 of 18 (38.8%) patients if a cutoff point were used. In multivariable analysis, EGFR GCN testing provided significant information independent of the KRAS status to predict response (P = 0.016) and overall survival (P = 0.005). CONCLUSIONS: We confirm the association between increased EGFR GCN and outcome after cetuximab. However, because of reproducibility concerns, any decision making based on published cutoff points is not warranted.     

Efficacy of primed in situ labelling in determination of HER-2 gene amplification and CEN-17 status in breast cancer tissue

Considerable attention has been given to the accuracy of HER-2 testing and the correlation between the results of different testing methods. This interest reflects the growing importance of HER-2 status in the management of patients with breast cancer. In this study the detection of HER-2 gene and centromere 17 status was evaluated using dual-colour primed in situ labelling (PRINS) in comparison with fluorescence in situ hybridization (FISH). These two methods were evaluated on a series of 27 formalin fixed paraffin embedded breast carcinoma tumours, previously tested for protein overexpression by HercepTest (grouped into Hercep 1+/0, 2+ and 3+). HER-2 gene amplification (ratio ≥ 2.2) by PRINS was found in 3:3, 6:21 and 0:3 in IHC 3+, 2+ and 1+/0 cases, respectively. Comparing FISH and IHC (immunohistochemistry), showed the same results as for PRINS and IHC. Chromosome 17 aneusomy was found in 10 of 21 IHC 2+ cases (47.6%), of which 1 (10%) showed hypodisomy (chromosome 17 copy number per cell ≤ 1.75), 7 (70%) showed low polysomy (chromosome 17 copy number per cell=2.26 - 3.75) and 2 (20%) showed high polysomy (chromosome 17 copy number per cell ≥ 3.76). The overall concordance of detection of HER-2 gene amplification by FISH and PRINS was 100% (27:27). Furthermore, both the level of HER-2 amplification and copy number of CEN17 analysis results correlated well between the two methods. In conclusion, PRINS is a reliable, reproducible technique and in our opinion can be used as an additional test to determine HER-2 status in breast tumours.     

Evaluation of the epidermal growth factor receptor (EGFR) in colorectal tumours and lymph node metastases

Overexpression of the epidermal growth factor receptor (EGFR) often correlates with an aggressive tumour phenotype and poor prognosis. To examine the relevance of EGFR in colorectal cancer, we determined the expression of EGFR protein in 249 colorectal adenocarcinomas and 42 lymph node metastases using immunohistochemistry. Moreover, we investigated a (CA)(n) dinucleotide repeat polymorphism of the EGFR gene in a subset of 114 tumours. High levels of EGFR protein were observed in 123/249 (49.4%) samples. EGFR expression in colorectal carcinomas correlated with differentiation grade (P=0.014). However, there were no associations with Dukes' stage, site, patient age or gender. EGFR protein expression did not influence survival in this colorectal cancer patient cohort (P>or=0.05). Expression was not identical in paired colorectal tumours and lymph node metastases, with only 17/42 (40.5%) samples showing equivalent EGFR levels (P>0.05). The distribution of the (CA)(n) dinucleotide repeat alleles in colorectal adenocarcinomas was not associated with EGFR protein expression (P>0.05). These results indicate that while EGFR overexpression is a common event in colorectal carcinogenesis, it does not influence patient prognosis.