Epidermal Growth Factor Receptor Copy Number Gain Research Articles

The association of EGFR amplification with aberrant exon 20 insertion report using the cobas EGFR Mutation Test v2.

Determining the exact type of epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutation in lung cancer has become important. We found that not all ex20ins mutations reported by cobas EGFR test v2 could be validated by Sanger sequencing even using surgical specimens with high tumor contents. This study aimed to validate the ex20ins results reported by the cobas test and to determine whether there were clinicopathological factors associated with aberrant cobas ex20ins report. In total, 123 cobas-reported cases with ex20ins were retrospectively collected and validated by Sanger sequencing and Idylla assay. Clinicopathological features between ex20ins cobas+/Sanger+ group (n = 71) and cobas+/Sanger- group (n = 52) were compared. The Idylla assay detected ex20ins in 82.6% of cobas+/Sanger+ cases but only in 4.9% of cobas+/Sanger- cases. The cobas+/Sanger- group was significantly associated with higher tumor contents, poorly differentiated patterns, tumor necrosis, and a lower internal control cycle threshold value reported by the Idylla which suggesting the presence of increased EGFR gene copy numbers. EGFR fluorescence in situ hybridization (FISH) revealed the majority of cobas+/Sanger- group had EGFR high copy number gain (16%) or amplification (76%) according to the Colorado criteria. Among cases reported to have concomitant classic EGFR and ex20ins mutations by the cobas, the classic EGFR mutations were all detected by Sanger sequencing and Idylla, while the ex20ins mutations were undetected by Sanger sequencing (0%) or rarely reported by Idylla assay (3%). FISH revealed high EGFR copy number gain (17.9%) and amplification (79.5%) in cases reported having concomitant classic EGFR and ex20ins mutations by the cobas. This study demonstrated an unusually high frequency of EGFR amplification in cases with aberrant cobas ex20ins report which could not be validated by Sanger sequencing or Idylla assay. Ex20ins reported by the cobas test should be validated using other methods especially those reported having concomitant ex20ins and classic EGFR mutations.

Genomic characterisation of de novo EGFR copy number gain and its impact on the efficacy of first-line EGFR-tyrosine kinase inhibitors for EGFR mutated non-small cell lung cancer

BackgroundNon-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation generally respond well to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). However, genomic characterisation of de novo EGFR copy number gain (CNG) and its impact on the efficacy of first-line EGFR-TKIs remains unclear. MethodsThis multicenter, retrospective and real-world study included two cohorts that enroled EGFR mutant NSCLC patients. EGFR CNG was tested by next-generation sequencing of untreated tissue specimens. Cohort 1 detected the impact of EGFR CNG on first-line EGFR-TKIs treatment, and cohort 2 explored the genomic characterisation. ResultsCohort 1 enroled 355 patients from four cancer centres between January 2013 and March 2022. The patients were divided into three groups, included the EGFR non-CNG, EGFR CNG, and EGFR uncertain-CNG. No significant difference in progression-free survival (PFS) was found between the three groups (10.0 months vs. 10.8 months vs. 9.9 months, respectively, p = 0.384). Furthermore, the overall response rate was not statistically significant in the EGFR CNG group compared to the EGFR non-CNG or uncertain arm (70.3% vs. 63.2% vs. 54.5%, respectively, p = 0.154). Cohort 2 included 7876 NSCLC patients with 16.4% showing EGFR CNG. Gene mutations such as TP53, IKZF1, RAC1, MYC, MET, CDKN2A/B and alterations of the metabolic-related and ERK signalling pathway were significantly associated with patients with EGFR CNG compared to those without. ConclusionsDe novo EGFR CNG had no effect on the efficacy of first-line EGFR-TKI treatment in EGFR mutant NSCLC patients, and tumours with EGFR CNG had more complex genomic profiles than those without.

PD-L1 expression, tumor-infiltrating lymphocytes, mismatch repair deficiency, EGFR alteration and HPV infection in sinonasal squamous cell carcinoma

The antitumor efficacies of immune checkpoint inhibitors (ICIs) and the usefulness of potential predictive markers such as programmed death-ligand 1 (PD-L1) expression, density of tumor-infiltrating lymphocytes (TILs) and microsatellite instability (MSI) in sinonasal squamous cell carcinoma (SNSCC) have not been fully elucidated. We retrospectively analyzed 131 SNSCCs with immunohistochemistry for PD-L1 expression, TIL subpopulations and loss of mismatch repair (MMR) proteins as a surrogate for MSI-high. We also comprehensively evaluated the mutual relationships among these immuno-markers, high-risk human papillomavirus (HPV) infection, epidermal growth factor receptor (EGFR) gene status, and KRAS mutation. PD-L1 expression (tumor proportion score ≥ 1%) was detected in 60 (45.8%) SNSCC cases and was significantly associated with worse overall survival (OS) (p = 0.0240). High density of cluster of differentiation 8 (CD8)-positive TILs was significantly associated with better progression-free survival (PFS) (p = 0.0368), and high density of forkhead box protein P3-positive TILs was significantly associated with better PFS and OS (p = 0.0007 and 0.0143, respectively). With respect to the combination of CD8 + TIL and PD-L1 expression, the high-CD8/PD-L1-negative group showed the most favorable prognosis, whereas the low-CD8/PD-L1-positive group showed the worst prognosis. MMR loss was detected in 3 (2.3%) of the 131 cases. HPV infection (6.1%), EGFR mutation (14.5%), EGFR copy number gain (26%), and MMR loss were essentially mutually exclusive; patients in these molecular groups showed significant differences in prognosis but not in the degree of PD-L1 expression or TILs. Among the nine ICI-treated patients, three (33.3%) were responders, and the EGFR-wild type cases (n = 7) showed better clinical responses to an ICI compared to the EGFR-mutant cases (n = 2). Among the patients with residual/recurrent EGFR-wild type tumors (n = 43), ICI treatment significantly improved OS (p = 0.0281). The results suggest that the evaluation of immuno-markers and molecular subclassification may be helpful for prognostic prediction and selecting an individualized therapeutic strategy for patients with SNSCC.

Clinical Value of EGFR Copy Number Gain Determined by Amplicon-Based Targeted Next Generation Sequencing in Patients with EGFR-Mutated NSCLC.

BackgroundThe clinical relevance of epidermal growth factor receptor (EGFR) copy number gain in patients with EGFR mutated advanced non-small cell lung cancer on first-line tyrosine kinase inhibitor treatment has not been fully elucidated.ObjectiveWe aimed to estimate EGFR copy number gain using amplicon-based next generation sequencing data and explored its prognostic value.Patients and MethodsNext generation sequencing data were obtained for 1566 patients with non-small cell lung cancer. EGFR copy number gain was defined based on an increase in EGFR read counts relative to internal reference amplicons and normal controls in combination with a modified z-score ≥ 3.5. Clinical follow-up data were available for 60 patients treated with first-line EGFR-tyrosine kinase inhibitors.ResultsSpecificity and sensitivity of next generation sequencing-based EGFR copy number estimations were above 90%. EGFR copy number gain was observed in 27.9% of EGFR mutant cases and in 7.4% of EGFR wild-type cases. EGFR gain was not associated with progression-free survival but showed a significant effect on overall survival with an adjusted hazard ratio of 3.14 (95% confidence interval 1.46–6.78, p = 0.003). Besides EGFR copy number gain, osimertinib in second or subsequent lines of treatment and the presence of T790M at relapse revealed significant effects in a multivariate analysis with adjusted hazard ratio of 0.43 (95% confidence interval 0.20–0.91, p = 0.028) and 0.24 (95% confidence interval 0.1–0.59, p = 0.001), respectively.ConclusionsPre-treatment EGFR copy number gain determined by amplicon-based next generation sequencing data predicts worse overall survival in EGFR-mutated patients treated with first-line EGFR-tyrosine kinase inhibitors. T790M at relapse and subsequent treatment with osimertinib predict longer overall survival.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11523-021-00798-2.

HPV-related Sinonasal Carcinoma: Clinicopathologic Features, Diagnostic Utility of p16 and Rb Immunohistochemistry, and EGFR Copy Number Alteration.

The prevalence and prognostic value of human papillomavirus (HPV) infection and epidermal growth factor receptor (EGFR) alteration in sinonasal squamous cell carcinoma (SNSCC) are not known. The reliability of p16 overexpression as a surrogate for HPV infection in SNSCC is also unclear. We investigated the prognostic and diagnostic significances of HPV infection, EGFR alteration, and p16 expression in SNSCC. We analyzed high-risk HPV infection by HPV-RNA in situ hybridization and EGFR gene copy number gain (CNG) by chromogenic in situ hybridization and by determining the protein expressions of p16, Rb, and EGFR by immunohistochemistry in 101 SNSCC cases. HPV infection (n=9, 8.9%) and p16 overexpression (n=15, 14.9%) were associated with better overall survival (P=0.0042 and 0.005, respectively). The HPV cases were located predominantly at the nasal cavity with nonkeratinizing histology and partial loss of Rb. Notably, 40% (6/15) of p16 SNSCCs were HPV. Two of these cases showed complete loss of Rb expression by immunohistochemistry, suggesting a reason for the above discrepancy. EGFR CNG, detected in 30.5% of the SNSCCs, was correlated with EGFR protein overexpression (P=0.0001). HPV infection and EGFR CNG were mutually exclusive. The HPV/EGFR CNG group had significantly better overall survival than the HPV/EGFR CNG and HPV/EGFR CNG groups (P=0.0471 and 0.0343, respectively). Our results suggest that HPV infection is a favorable prognostic marker in SNSCC, but p16 is not a perfect surrogate marker; the Rb expression pattern may improve the diagnostic accuracy. The molecular subclassification of SNSCCs based on HPV infection and EGFR copy number status might provide important information for therapeutic strategies.

Gefitinib and EGFR Gene Copy Number Aberrations in Esophageal Cancer.

Purpose The Cancer Esophagus Gefitinib trial demonstrated improved progression-free survival with the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor gefitinib relative to placebo in patients with advanced esophageal cancer who had disease progression after chemotherapy. Rapid and durable responses were observed in a minority of patients. We hypothesized that genetic aberration of the EGFR pathway would identify patients benefitting from gefitinib. Methods A prespecified, blinded molecular analysis of Cancer Esophagus Gefitinib trial tumors was conducted to compare efficacy of gefitinib with that of placebo according to EGFR copy number gain (CNG) and EGFR, KRAS, BRAF, and PIK3CA mutation status. EGFR CNG was determined by fluorescent in situ hybridization (FISH) using prespecified criteria and EGFR FISH-positive status was defined as high polysomy or amplification. Results Biomarker data were available for 340 patients. In EGFR FISH-positive tumors (20.2%), overall survival was improved with gefitinib compared with placebo (hazard ratio [HR] for death, 0.59; 95% CI, 0.35 to 1.00; P = .05). In EGFR FISH-negative tumors, there was no difference in overall survival with gefitinib compared with placebo (HR for death, 0.90; 95% CI, 0.69 to 1.18; P = .46). Patients with EGFR amplification (7.2%) gained greatest benefit from gefitinib (HR for death, 0.21; 95% CI, 0.07 to 0.64; P = .006). There was no difference in overall survival for gefitinib versus placebo for patients with EGFR, KRAS, BRAF, and PIK3CA mutations, or for any mutation versus none. Conclusion EGFR CNG assessed by FISH appears to identify a subgroup of patients with esophageal cancer who may benefit from gefitinib as a second-line treatment. Results of this study suggest that anti-EGFR therapies should be investigated in prospective clinical trials in different settings in EGFR FISH-positive and, in particular, EGFR-amplified esophageal cancer.

Dysregulation and detection methods of EGFR in oral cancer. A narrative review.

Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein, with an intracellular domain and tyrosine kinase function (TK) involved in cell proliferation. Dysfunctions in EGFR signaling pathways have been associated with oral malignant tumors such as oral squamous cell carcinoma (OSCC). Dysfunctions of EGFR may result from: increased EGF ligand; EGFR overexpression and copy number gain of the EGFR gene (EGFR CNG); EGFR mutations; failure in the downregulation of EGFR; and EGFR crosstalk. Of these alterations, overexpression of EGFR is by far the most studied dysfunction in OSCC. Clinicians should identify possible alterations of EGFR in the oral mucosa of patients, as EGFR can act as a biomarker for the diagnosis and prognosis of OSCC. Currently, there are several methods and techniques for detecting EGFR. Immunohistochemistry (IHC), fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR), are used to identify overexpression of EGFR, EGFR CNG and EGFR mutations, respectively. Detection of EGFR as a biomarker is key to identify any oral malignant transformation. Consequently, it becomes imperative to implement a non-invasive and inexpensive method of early diagnosis for OSCC in clinical practice.

Impact of epidermal growth factor receptor protein and gene alteration on Taiwanese hepatocellular carcinomas.

Epidermal growth factor receptor (EGFR) overexpression is associated with disease progression and poor survival in a variety of solid tumors. The role of EGFR in hepatocellular carcinoma (HCC) remains controversial. One hundred thirty-eight HCCs were analyzed for total EGFR (t-EGFR) and phospho-EGFR (p-EGFR) expression and gene amplification using immunohistochemistry and fluorescence in situ hybridization. The role of EGFR was analyzed in relation to the clinicopathological features. Weak to strong p-EGFR immunostaining was noted in 42 of the 138 HCCs. p-EGFR expression correlated with alcoholism (P = 0.03) and chronic hepatitis B infection (P = 0.041). There was no correlation between t-EGFR expression and any of the clinicopathological features. Amplification of the EGFR gene was not identified in the 138 HCCs, but 39.1% of the HCCs showed balanced polysomy of both the EGFR gene and centromere 7. Moreover, 65 tumors showed > 2.2 copies per tumor cell. EGFR copy number gain (CNG) was significantly correlated with gender (P = 0.0491), tumor grade (P = 0.006), and vascular invasion (P = 0.005). HCCs with EGFR CNG also had a poor recurrence-free survival (RFS), as compared with HCCs without EGFR CNG (P = 0.031). When exploring the impact of gender, a significant association of EGFR CNG was found with tumor grade (P = 0.044) and cirrhosis (P = 0.015) exclusively in the male group only; however, the OS and RFS analysis show no significant difference between male and female groups. EGFR CNG was related to crucial clinicopathological features and early recurrence, indicating that EGFR CNG might be a poor prognosis factor for Taiwanese HCC.

Abstract 2396: High EGFR gene copy number predicts poor outcome in triple-negative breast cancer.

Abstract INTRODUCTION: Epidermal growth factor receptor (EGFR) is frequently expressed in triple-negative breast cancer and is emerging as a new therapeutic target. However, the rate of EGFR gene copy number alteration and mutation has been reported to be quite variable and their prognostic significance is poorly defined in triple-negative breast cancer. METHOD: We examined EGFR protein expression, gene copy number alteration and mutation in 150 cases of tripe-negative breast cancer and correlated their findings with clinical outcome of the patients. EGFR protein expression was evaluated by immunohistochemistry using whole tissue sections and EGFR copy number alteration was assessed by dual-color fluorescence in situ hybridization using tissue microarrays. EGFR mutation analysis was performed by polymerase chain reaction of exon 18 to 21 of EGFR gene and direct sequencing of PCR products. RESULT: EGFR protein was expressed in 117 of 150 cases (78.0%). High EGFR gene copy number was found in 33.3% of the cases (amplification in 2.0% and high polysomy in 31.3%). Five EGFR mutations were detected in 4 of 150 cases (2.7%) with G719A in exon 18 (n=1), V786M in exon 20 (n=1) and L858R in exon 21 (n=3). One case had two mutations (G719A and L858R). High EGFR copy number, but not EGFR mutation, was correlated with EGFR protein over-expression. In survival analyses, high EGFR copy number gain was found to be a poor prognostic factor for relapse-free survival (p=0.046), especially for metastasis-free survival (p=0.016). CONCLUSION: EGFR mutation is found to be a rare event in triple-negative breast cancer. However, high EGFR copy number is relatively frequent and is associated with poor clinical outcome in triple-negative breast cancer, suggesting that evaluation of EGFR gene copy number is beneficial for the prediction of outcome in patients with triple-negative breast cancer and selection of the patients for anti-EGFR targeted therapy. Citation Format: Heae Surng Park, Min Hye Jang, Eun Joo Kim, Hyun Jeong Kim, Hee Jin Lee, So Yeon Park. High EGFR gene copy number predicts poor outcome in triple-negative breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2396. doi:10.1158/1538-7445.AM2013-2396

Concomitant high gene copy number and protein overexpression of IGF1R and EGFR negatively affect disease-free survival of surgically resected non-small-cell-lung cancer patients.

Insulin-like growth factor 1 receptor (IGF1R) represents a novel molecular target in non-small-cell-lung cancer (NSCLC). IGF1R and epidermal growth factor receptor (EGFR) activation are essential to mediate tumor cell survival, proliferation, and invasion. This study investigates the prognostic role of IGF1R and EGFR in surgically resected NSCLC. IGF1R and EGFR copy number gain (CNG) were tested by fluorescence in situ hybridization (FISH) and protein expression by immunohistochemistry (IHC) in 125 stage I-II-IIIA NSCLC patients. Fourty-six tumors (40.3%) were IGF1R FISH-positive (FISH+), and 76 (67.2%) were EGFR FISH+. Tumors with concomitant IGF1R/EGFR FISH+ were observed in 34 cases (30.1%). IGF1R and EGFR FISH+ were associated with SCC histology (p = 0.01 and p = 0.04, respectively). IGF1R and EGFR protein over-expression (IHC+) were detected in 45 (36.0%) and 69 (55.2%) cases, respectively. Tumors with concomitant IGF1R/EGFR IHC+ were detected in 31 (24.8%) patients. IGF1R/EGFR FISH+ and IGF1R/EGFR IHC+ were significantly associated (χ(2) = 4.02, p = 0.04). Patients with IGF1R/EGFR FISH+ and IGF1R/EGFR IHC+ were associated with shorter disease-free survival (DFS) (p = 0.05 and p = 0.05, respectively). Patients with concomitant IGF1R/EGFR FISH+/IHC+ had a worse DFS and overall survival (p = 0.005 and p = 0.01, respectively). The multivariate model confirmed that IGF1R/EGFR FISH+/IHC+ (hazard ratio (HR), 4.08; p = 0.01) and tumor stage (II-III vs I) (HR, 4.77; p = 0.003) were significantly associated with worse DFS. IGF1R/EGFR FISH+ correlates with IGF1R/EGFR IHC+. IGF1R/EGFR FISH+/IHC+ is an independent negative prognostic factor for DFS in early NSCLC. These features may have important implications for future anti-IGF1R therapeutic approaches.

Epidermal growth factor receptor protein expression and genomic alterations in renal cell carcinoma

Epidermal growth factor receptor (EGFR) is involved in the progression of many cancer types and represents an important therapeutic target. To determine the role of EGFR in renal cell carcinoma (RCC), the authors analyzed 1088 tumors in a tissue microarray format by using immunohistochemistry and fluorescence in situ hybridization (FISH). A subset of 63 cancers was sequenced for EGFR exon 18 through 21 mutations. EGFR expression was observed in 83.8% of clear cell carcinomas, in 68.2% of papillary carcinomas, in 75% of chromophobe carcinomas, and in 50% of oncocytomas. Within clear cell carcinomas, the expression level of EGFR was associated with high tumor grade (P < .0001), advanced pathologic tumor classification (P < .0001), and, to a lesser extent, lymph node status (P = .0326). FISH analysis revealed increased EGFR copy numbers (high polysomy) in 5.5% of tumors and amplification in 0.1% of tumors. EGFR copy number increases were associated with EGFR protein expression (P = .0015). Within clear cell carcinomas, EGFR copy number increases were associated with high tumor grade (P < .0001), advanced pathologic tumor classification (P = .0472), and lymph node status (P = .0065). No exon 18 through 21 mutations were identified in 63 sequenced tumors. The authors concluded that increased EGFR expression occurs in a fraction of patients who have RCC with an unfavorable histologic phenotype. EGFR copy number gain represents 1 possible cause for EGFR overexpression; however, many over expressing tumors have a normal genotype. High polysomy (which is suggested to be predictive of a response to tyrosine kinase inhibitors) occurs in 5.6% of RCCs. Thus, the potential utility of anti-EGFR medications may be worth further investigation in a small but significant subset of patients with RCC.

Insulin-like growth factor receptor-1 (IGF1R) and epidermal growth factor receptor (EGFR) amplification and expression in surgically resected NSCLC.

10519 Background: IGF1R represents a novel molecular target in non-small cell lung cancer (NSCLC). IGF1R and EGFR activation is essential to mediate tumor cell survival, proliferation and invasion. This study investigates the prognostic role of IGF1R and EGFR copy number gain (CNG) by fluorescence in situ hybridization (FISH) and protein overexpression by immunohistochemistry (IHC) in surgically resected NSCLC. Methods: 114 NSCLC patients were evaluated; median age was 66y (range 40–84), Male/Female:96/18; squamous (SCC)/adeno/BAC/other:59/34/9/12; smoker/never smoker:105/9, and stage I/II/III:71/18/25. IGF1R and EGFR FISH were tested by customized and commercial probes, respectively; positive specimens showed gene amplification or polysomy (≥4 copies in ≥10% of tumor cells). IGF1R and EGFR protein expression were evaluated using mouse antibodies (clones 24-31 and 3147, respectively); overexpression was defined by ≥10% positive cells. Kaplan-Meier estimates of survival and time to recurrence were calculated for clinical and biologic variables using Cox model for multivariate analysis. Results: 46 tumors (40%) were IGF1R FISH+ and 76 (77%) were EGFR FISH+. IGF1R FISH+ was associated with EGFR FISH+ (p=0.03) and co-amplification was observed in 34 cases (30%). IGF1R and EGFR FISH+ were associated with SCC (p=0.01 and p=0.05, respectively). IGF1R and EGFR overexpression was detected in 36% and 55% of NSCLC patients and co-expression was detected in 25%. Co-amplification and co-expression of both receptors were significantly associated (p=0.045). IGF1R and EGFR co-amplification and co-expression associated with shorter disease free survival (DFS; p=0.05, p=0.05 respectively), also at multivariate analysis adjusting for stage (p=0.0002). Conclusions: IGF1R and EGFR are frequently co-amplified in NSCLC and CNG correlates with protein overexpression. Both co-amplification and co-expression of IGF1R and EGFR predicts shorter DFS. These results provide a strong rational for targeting simultaneously EGFR and IGF1R in clinical trials for NSCLC. We thank the Italian Association for Cancer Research (AIRC) for supporting the study (AF Fellowship).

EGFR Gene Copy Number Gain is Related to High Tumor SUV and Frequent Relapse after Adjuvant Chemotherapy in Resected Lung Adenocarcinoma

The purpose of our study was to define the prognostic impact of increased copies of epidermal growth factor receptor (EGFR) gene in lung adenocarcinoma patients receiving adjuvant chemotherapy after surgery. The study included 95 adenocarcinoma patients who received curative resection for non-small cell lung cancer. Patients received adjuvant chemotherapy composed of paclitaxel and carboplatin. We performed fluorescent in situ hybridization on tissue microarray in duplicate to detect EGFR copy number change. The EGFR fluorescent in situ hybridization result was available in 93 patients with a positive rate of 32.6%. EGFR copy number change did not correlate with age, gender or smoking history. However, EGFR copy number gain was related to high tumor standardized uptake value at diagnosis (P = 0.042). An increase in EGFR copy number was a negative prognostic factor in terms of disease-free survival (median disease-free survival not reached versus 23.6 months, P = 0.037) and overall survival (median overall survival 74.6 versus 43.5 months, P = 0.032). An increase in EGFR copy number was independently related to short disease-free survival in multivariate analysis (hazard ratio 2.039, P = 0.025). EGFR copy number gain is associated with aggressive tumor biology and is a poor prognostic factor for tumor relapse in resected lung adenocarcinoma patients receiving adjuvant chemotherapy of paclitaxel and carboplatin.

HER family receptor abnormalities in lung cancer brain metastases and corresponding primary tumors.

To compare the characteristics of deregulation of HER receptors and their ligands between primary tumor and corresponding brain metastases of non-small cell lung carcinoma (NSCLC). Fifty-five NSCLC primary tumors and corresponding brain metastases specimens were examined for the immunohistochemical expression of epidermal growth factor receptor (EGFR), phosphorylated EGFR, Her2, Her3, and phosphorylated Her3, and their ligands EGF, transforming growth factor-alpha, amphiregulin, epiregulin, betacellulin, heparin-binding EGFR-like growth factor, neuregulin (NRG) 1, and NRG2. Analysis of EGFR copy number using fluorescence in situ hybridization and mutation by PCR-based sequencing was also done. Metastases showed significantly higher immunohistochemical expression of EGF (membrane: brain metastases 66.0 versus primary tumors 48.5; P = 0.027; nucleus: brain metastases 92.2 versus 67.4; P = 0.008), amphiregulin (nucleus: brain metastases 53.7 versus primary tumors 33.7; P = 0.019), phosphorylated EGFR (membrane: brain metastases 161.5 versus primary tumors 76.0; P < 0.0001; cytoplasm: brain metastases 101.5 versus primary tumors 55.9; P = 0.014), and phosphorylated Her3 (membrane: brain metastases 25.0 versus primary tumors 3.7; P = 0.001) than primary tumors did. Primary tumors showed significantly higher expression of cytoplasmic transforming growth factor-alpha(primary tumors 149.8 versus brain metastases 111.3; P = 0.008) and NRG1 (primary tumors 158.5 versus brain metastases 122.8; P = 0.006). In adenocarcinomas, a similar high frequency of EGFR copy number gain (high polysomy and amplification) was detected in primary (65%) and brain metastasis (63%) sites. However, adenocarcinoma metastases (30%) showed higher frequency of EGFR amplification than corresponding primary tumors (10%). Patients whose primary tumors showed EGFR amplification tended to develop brain metastases at an earlier time point. Our findings suggest that NSCLC brain metastases have some significant differences in HER family receptor-related abnormalities from primary lung tumors.

EGFR amplification and lack of activating mutations in metaplastic breast carcinomas

Metaplastic breast carcinomas are reported to harbour epidermal growth factor receptor (EGFR) overexpression in up to 80% of the cases, but EGFR gene amplification is the underlying genetic mechanism in around one-third of these. In this study, EGFR gene amplification as defined by chromogenic in situ hybridization and protein overexpression was examined in a cohort of 47 metaplastic breast carcinomas. Furthermore, the presence of activating EGFR mutations in exons 18, 19, 20, and 21 was investigated. Thirty-two cases showed EGFR overexpression and of these, 11 (34%) harboured EGFR gene amplification. In addition, EGFR amplification showed a statistically significant association with EGFR overexpression (p < 0.0094) and was restricted to carcinomas with homologous metaplasia. Ten cases, five with and five without EGFR amplification, were subjected to microarray-based CGH, which demonstrated that EGFR copy number gain may occur by amplification of a discrete genomic region or by gains of the short arm of chromosome 7 with a breakpoint near the EGFR gene locus, the minimal region of amplification mapping to EGFR, LANCL2, and SEC61G. No activating EGFR mutations were identified, suggesting that this is unlikely to be a common alternative underlying genetic mechanism for EGFR expression in metaplastic breast carcinomas. Given that metaplastic breast carcinomas are resistant to conventional chemotherapy or hormone therapy regimens and that tumours with EGFR amplification are reported to be sensitive to EGFR tyrosine kinase inhibitors, these findings indicate that further studies are warranted to explore EGFR tyrosine kinase inhibitors as potential therapeutic agents for metaplastic breast carcinomas harbouring amplification of 7p11.2.