Epidermal Growth Factor Receptor Polysomy Research Articles

EGFR alterations and EML4-ALK rearrangement in primary adenocarcinoma of the urinary bladder

The identification of mutations in epidermal growth factor receptor (EGFR) and translocations involving anaplastic lymphoma kinase (ALK) in lung adenocarcinoma has drastically changed understanding of the disease and led to the development of targeted therapies. Adenocarcinoma of the urinary bladder is rare and poorly understood at the molecular level. We undertook this study to determine whether EGFR mutations, increases in EGFR copy number, or ALK translocations are present in these tumors. Twenty-eight cases of primary bladder adenocarcinoma were analyzed. For EGFR mutational analysis, PCR-amplified products were analyzed on the Q24 Pyrosequencer with Qiagen EGFR Pyro Kits. All cases were analyzed via fluorescence in situ hybridization (FISH) using Vysis ALK Break Apart FISH Probes for detection of ALK chromosomal translocation and Vysis Dual Color Probes to assess for increased gene copy number of EGFR. None of the 28 cases examined showed mutational events in EGFR or ALK rearrangements. EGFR polysomy was seen in 10 out of 28 (36%) cases. No correlation with EGFR polysomy was seen in the tumors with respect to age, histologic subtypes, pathologic stage, or lymph node metastasis. In summary, EGFR mutations and ALK rearrangements do not appear to be involved in the development of primary adenocarcinoma of the urinary bladder. A subgroup of cases (36%), however, demonstrated increased gene copy number of EGFR by FISH.

Rhabdoid glioblastoma is distinguishable from classical glioblastoma by cytogenetics and molecular genetics

The clinicopathologic and molecular genetic features of 5 cases of rhabdoid glioblastoma, an extremely rare variant of glioblastoma that tends to affect patients at a young age, were investigated by immunohistochemical analysis and focused molecular genetic studies including array-based comparative genomic hybridization. All 5 cases had supratentorial tumors that immunohistochemical analysis revealed to be robustly positive for epithelial membrane antigen, vimentin, p53, and PDGFRα (platelet-derived growth factor receptor, alpha polypeptide) but only focally positive for glial fibrillary acidic protein. Although complete retention of SMARCB1 (INI1) was observed in all 5 cases, epidermal growth factor receptor (EGFR) amplification, PTEN (phosphatase and tensin homolog) loss, homozygous deletion of cyclin-dependent kinase inhibitor 2A, 1p/19q codeletion, and isocitrate dehydrogenase 1 R132/IDH2 R172 mutation were not observed in any case, although a high level of EGFR polysomy was detected in 1 recurrent tumor. Although c-MET (MET protein) expression was focal but robustly positive in 3 cases, met proto-oncogene (MET) fluorescence in situ hybridization revealed low polysomy but not MET amplification. MGMT (O-6-methylguanine-DNA methyl-40 transferase) methylation-specific polymerase chain reaction revealed MGMT methylation in only 1 case. Furthermore, array-based comparative genomic hybridization revealed gain of chromosome 7 and loss of 1p, 6, 8p, 11, 13q, and 18q but no deletion of chromosome 22. In contrast to the classical subtype of primary glioblastoma, the cases studied here were characterized by the absence of EGFR amplification, PTEN loss, and 9p homozygous deletion and overexpression of p53, PDGFRα, and c-MET, suggesting that they can be classified as the proneural or mesenchymal subtype of glioblastoma and benefit from intensive therapy that includes temozolomide.

EGFR in melanoma: clinical significance and potential therapeutic target

The role of epidermal growth factor receptor (EGFR) has been established in a range of neoplasms. In melanoma, data on EGFR protein expression are conflicting. Fluorescence in situ hybridization (FISH) analysis for EGFR gene expression in melanoma showed EGFR gene amplification to be linked with worse prognosis. Cetuximab has been shown to suppress the formation of metastasis in mice. EGFR protein expression and gene copy number status were evaluated by means of immunohistochemistry and FISH in melanoma samples of patients with known clinicopathological data. Associations between EGFR expression and prognostic parameters were investigated. The effect of different cetuximab concentrations on the BLM melanoma cell line was evaluated by means of methyl tetrazolium (MTT), sulforhodamine B (SRB) and Matrigel invasion assays. EGFR protein expression was more frequently observed in patients with a positive sentinel lymph node. However, EGFR immunostaining has no predictive value. The presence of EGFR polysomy was associated with thicker tumors. Treatment of the BLM melanoma cell line with different concentrations of cetuximab reduced the invasive capacity of the cells, but did not alter cell viability or growth. EGFR appears to be involved in progression and metastasis of a subset of melanomas. Targeting EGFR could therefore represent a therapeutic option for these melanomas.

The role of epidermal growth factor receptor in chordoma pathogenesis: a potential therapeutic target

Chordoma, the molecular hallmark of which is T (brachyury), is a rare malignant bone tumour with a high risk of local recurrence and a tumour from which metastatic disease is a common late event. Currently, there is no effective drug therapy for treating chordomas, although there is evidence that some patients respond to the empirical use of epidermal growth factor receptor (EGFR) antagonists. The aim of this study was to determine the role of EGFR in the pathogenesis of chordoma. Paraffin-embedded material from 173 chordomas from 160 patients [sacro-coccygeal (n = 94), skull-based (n = 50), and mobile spine (n = 16)] was analysed by immunohistochemistry and revealed total EGFR expression in 69% of cases analysed. Of 147 informative chordomas analysed by FISH, 38% revealed high-level EGFR polysomy, 4% high-level polysomy with focal amplification, 18% low-level polysomy, and 39% disomy. Phospho-receptor tyrosine kinase array membranes showed EGFR activation in the chordoma cell line U-CH1 and all of the three chordomas analysed. Direct sequencing of EGFR (exons 18-21), KRAS, NRAS, HRAS (exons 2, 3), and BRAF (exons 11, 15) using DNA from 62 chordomas failed to reveal mutations. PTEN expression was absent by immunohistochemistry in 19 of 147 (13%) analysed chordomas, only one of which revealed high-level polysomy of EGFR. The EGFR inhibitor tyrphostin (AG 1478) markedly inhibited proliferation of the chordoma cell line U-CH1 in vitro and diminished EGFR phosphorylation in a dose-dependant manner, a finding supported by inhibition of phosphorylated Erk1/2. p-Akt was suppressed to a much lesser degree in these experiments. There was no reduction of T as assessed by western blotting. These data implicate aberrant EGFR signalling in the pathogenesis of chordoma. This study provides a strategy for patient stratification for treatment with EGFR antagonists.

Prognostic Implications of Epidermal Growth Factor Receptor and KRAS Gene Mutations and Epidermal Growth Factor Receptor Gene Copy Numbers in Patients with Surgically Resectable Non-small Cell Lung Cancer in Taiwan

The prognostic role of epidermal growth factor receptor (EGFR) mutations in patients with surgically resectable non-small cell lung cancer (NSCLC) without EGFR tyrosine kinase inhibitor treatment has not been well established, because the reports are still few. We analyzed the survival data of 164 patients with surgically resectable (stages I to IIIA) NSCLC of two year groups (1996-1998 and 2002-2004), and compared with EGFR mutations, KRAS mutations, and EGFR gene copy numbers. Comparing the survival of wild-type patients and patients having L858R mutations or exon 19 deletion, the median survival was much longer for patient with EGFR mutations (54.7 months) than wild type (34.9 months). The difference was not statistically significant by univariate analysis (p = 0.1981) but had borderline significance by multivariate analyses (p = 0.0506). In addition, the 3-year survival rates of patients with EGFR mutations were also significantly higher than wild type (p = 0.0232). After exclusion of 18 patients treated by EGFR-tyrosine kinase inhibitor for tumor recurrence, the trends were still the same. Patients with KRAS mutations had shorter median survival (21 months) than wild type (44.4 months). Patients with EGFR polysomy (>==copies) also had longer median survival (56.2 months) than wild type (53.4 months). But the survival differences of these two genetic markers were all not significant statistically. It is intriguing that patients with NSCLC with EGFR mutations had better survival than wild type. Such a tumor biology may confound the survival data in a study without the stratification by EGFR mutation.

EGFR Polysomy in Squamous Cell Carcinoma of the Thyroid. Report of Two Cases and Review of the Literature

Primary squamous cell carcinoma of the thyroid gland (PSCCT) is an uncommon malignancy characterized by a poor prognosis. A radical surgical approach combined with radiotherapy or chemotherapy is the generally accepted treatment for this tumor. The epidermal growth factor receptor (EGFR) is a transmembrane tyrosine kinase receptor modulating the cell proliferation and biological progression of many human epithelial tumors. The EGFR overexpression in PSCCT suggests an additional therapeutic option for the treatment of this tumor. The clinicopathological features and immunohistochemical profiles of two cases of primary squamous cell carcinoma of the thyroid in a 66-year-old and an 83-year-old woman are presented. EGFR status was valued in both cases. Overexpression of EGFR protein was detected in 50% and 75% of the tumor cell membranes. EGRF gene polysomy was detected in both tumors. Pharmaceuticals targeting EGFR may help to provide the rationale for an additional, novel therapeutic option for this rare tumor, especially when other therapeutic options have been exhausted.

Overexpression and activation of EGFR and VEGFR2 in medullary thyroid carcinomas is related to metastasis

Therapeutic options for patients with metastatic medullary thyroid carcinoma (MTC) are limited due to lack of effective treatments. Thus, there is a need to thoroughly characterize the pathways of molecular pathogenesis and to identify potential targets for therapy in MTC. Since epidermal growth factor receptor (EGFR) seems to play a crucial role for RET activation, a key feature of MTCs, and several promising EGFR/vascular endothelial growth factor receptor 2 (VEGFR2)-targeted drugs have been developed, the present study was designed to investigate whether these proteins are altered in MTCs. We used a well-characterized series of 153 MTCs to evaluate EGFR activation by sequencing and FISH analysis, and to perform EGFR and VEGFR2 immunohistochemistry. EGFR tyrosine kinase domain mutations were not a feature of MTCs; however, EGFR polysomy and a strong EGFR expression were detected in 15 and 13% of the tumors respectively. Interestingly, EGFR was significantly overexpressed in metastases compared with primary tumors (35 vs 9%, P=0.002). We also studied whether specific RET mutations were associated with EGFR status, and found a decrease in EGFR polysomies (P=0.006) and a tendency towards lower EGFR expression for the most aggressive RET mutations (918, 883). Concerning VEGFR2, metastasis showed a higher expression than primary tumors (P=2.8 x 10(-8)). In this first study investigating the relationship between EGFR, RET, and VEGFR2 in a large MTC series, we found an activation of EGFR and VEGFR2 in metastasis, using both independent and matched primary/metastasis samples. This suggests that some MTC patients may benefit from existing anti-EGFR/VEFGR2 therapies, although additional preclinical and clinical evidence is needed.

Epidermal growth factor receptor gene amplification in surgical resected Japanese lung cancer

To evaluate the epidermal growth factor receptor (EGFR) protein expression and increased copy number as predictors of clinical outcome in patients with non-small-cell lung cancer (NSCLC), we have performed fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). We investigated the EGFR increased copy number and EGFR protein expression statuses in 109 surgically treated NSCLC cases. The presence or absence of EGFR mutations of kinase domains was analyzed by genotyping analysis and sequences, and already reported. EGFR increased copy number was defined as Cappuzzo et al. criteria. FISH positive was found from 36/109 (33.0%) lung cancer patients, including 30 high polysomy cases and 6 gene amplification cases. FISH-positive cases were significantly correlated with worse prognosis (log-rank test p = 0.0097). Within EGFR-mutant patients ( n = 55), FISH-positive cases were also correlated with poor prognosis ( p = 0.0255). FISH-negative tumors were found to be more frequently well-differentiated histology. Smoking status (never smoker vs. smoker, p = 0.1510), and gender ( p = 0.5248) did not correlated with FISH positive. EGFR IHC results were correlated with FISH results ( p = 0.004), but not correlated with prognosis ( p = 0.2815). Although EGFR FISH-positive rate did not correlated with EGFR mutation ( p = 0.1973), EGFR polysomy or amplification cases were correlated with EGFR mutations ( p = 0.0023). In conclusion, the EGFR FISH-positive rate in Japanese patients with NSCLC was similar to rates in Western populations, unlike the higher frequencies of EGFR mutation in East Asians. A high EGFR gene copy number might have shorter survival in NSCLC.

Sarcomatoid carcinoma of the upper urinary tract: clinical outcome and molecular characterization

Sarcomatoid carcinoma (carcinosarcoma) of the upper urinary collecting system is a rare aggressive malignancy composed of malignant epithelial and stromal components. Because of the paucity of reported cases, the clinical behavior, molecular alterations, and potential therapies for this malignancy are not well understood. Eight cases of sarcomatoid carcinoma involving the upper urinary tract were studied. Clinicopathologic characteristics were reviewed. Immunohistochemical expression of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2)/neu, c-kit, and p53 was analyzed in each case. Evaluation for amplification of EGFR and HER2 genes was performed by interphase fluorescence in situ hybridization (FISH). Each tumor was also examined for gains of chromosomes 3, 7, and 17 and for loss of chromosome 9p21 by UroVysion FISH (Vysis, Downers Grove, IL). The patients we studied were 5 females and 3 males, ranging in age from 56 to 78 years (mean age, 69 years). Presenting symptoms included gross hematuria, flank mass, urinary obstruction, fever, or sepsis. Radical nephroureterectomy was performed on all patients. Tumor size ranged from 2 to 13 cm. Coexisting urothelial carcinoma was present in all 8 cases. Heterologous osteosarcoma was identified in 2 cases. Pathologic stage was pT4 in 5 cases and pT3 in 3 cases. Lymph node metastases were present in 5 patients at the time of surgery. Of 8 patients, 7 died within 2 years after surgery. EGFR immunostaining had moderately to strongly positive results in 6 of 8 cases. Both HER2/neu and c-kit immunostaining had negative results in all cases. p53 immunostaining had positive results in 5 of 8 cases. The EGFR polysomy was demonstrated in 7 of 8 cases. No amplification of HER2/neu was present in any case. UroVysion FISH showed abnormalities typical of urothelial carcinoma in all 8 cases. In conclusion, the prognosis of sarcomatoid carcinoma of the upper urinary tract is extremely poor, most patients died within 2 years (7/8 patients). Gains of chromosome 3, 7, and 17 and loss of chromosome 9p21 were commonly observed in these tumors. Our findings suggest that targeted therapy may be a rational strategy in the management of these patients.

EGFR gene copy number alterations in primary cutaneous malignant melanomas are associated with poor prognosis

Copy number alterations of the epidermal growth factor receptor (EGFR) gene have been extensively analyzed in different cancers, but no data are available for primary malignant melanoma. The aim of the present study was to simultaneously investigate the EGFR gene and chromosome 7 copy number alterations in 81 cutaneous malignant melanomas by interphase FISH and correlate the data with clinicopathological parameters of patients. EGFR mRNA levels were detected by Affymetrix GeneChip Human Genome U133 Plus 2.0 expression arrays for 16 lesions. Both increased gene dosage and chromosome 7 alterations were found in 70% of tumors. Extra EGFR copies were detected in an additional 10% of samples. Polysomy 7 was associated with EGFR gene amplification. Significant correlation was found between EGFR alterations and histological subtypes, tumor thickness, ulceration and metastases formation. Amplification was significantly higher in lesions that developed metastases within 2 years after surgical excision of the primary tumor. Gene copy alterations were associated with elevated mRNA expression in 77% of lesions when compared to tumors with disomic EGFR status, the correlation was not directly proportional to gene copy number. Associations between protein expression and mRNA levels were even less prominent. In conclusion, our study indicates that amplification of the EGFR gene and polysomy 7 are frequent alterations in primary melanomas and are associated with bad prognosis. Further studies are required to clarify whether melanoma patients with EGFR alterations can benefit from anti-EGFR therapy.

Correlation of epidermal growth factor receptor (EGFR) mutation, immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH) in esophageal squamous cell carcinoma (ESCC)

4085 Background: ESCC remains a devastating cancer in Southern Thailand and novel therapeutic approach needs to be explored. EGFR tyrosine kinase (TK) inhibitor is a potential therapeutic agent against EGFR-expression tumors including ESCC. Forty-nine percent of ESCC patients in our institution overexpressed EGFR protein and 15% had EGFR gene amplification as published previously. Mutations within EGFR TK domain, particularly in exon 19 and 21, EGFR amplification or polysomy, and EGFR overexpression on IHC have all been associated with sensitivity and benefit to EGFR inhibitor treatment. To our best knowledge, no data on EGFR mutations in ESCC have been reported. This prompted us to perform analysis of EGFR mutations and correlate the status of each of these characteristics in ESCC. Methods: We studied 35 patients with ESCC whose data on EGFR IHC and FISH were available. DNA extraction was performed using a QIAamp DNA Kit. PCR for EGFR detection, using the oligonucleotide primers for amplification of exon 19 and 21, was sequenced and analyzed, using ABI Prism 377 sequencing analysis system and the Big Dye Terminator V3.0 Ready Reaction Cycle Sequencing Kit (ABI Prism). Results: Among 35 ESCC specimens evaluated, no EGFR somatic mutations in exon 19 or 21 were detected. Conclusions: EGFR mutations in exon 19 and 21 of ESCC were not identified in this study. EGFR overexpression and amplification do not correlate with EGFR mutation in Thai patients with ESCC. A clinical study of an EGFR inhibitor in esophageal carcinoma has been going on in our institution and the molecular markers as predictive factors need to be further evaluated and correlated with treatment outcome. No significant financial relationships to disclose.

Glioblastomas in the Older Old

Recent studies have identified fundamental biological differences in the effects of epidermal growth factor receptor (EGFR) amplification on survival in older versus younger patients with glioblastoma multiforme (GBM). Cell cycle labeling indices have also been found to be inordinately high in older GBM patients and may contribute to the known adverse prognosis in this cohort. However, testing has not been conducted on significant numbers of patients of very advanced age, in whom these features might be expected to emerge as even more significant factors. To assess EGFR amplification status and MIB-1 indices in patients with GBM who are older than 75 years. We identified 20 patients (female-male ratio, 11:9; 11 aged 75-79 years and 9 aged 80-87 years) and studied tumor tissue samples with immunohistochemistry for cell cycle labeling index and by fluorescence in situ hybridization for EGFR amplification. Survival data were obtained from the Colorado Tumor Registry. Mean MIB-1 index was high (24.8%), but individual indices did not correlate with survival. EGFR amplification was detected in 25% of cases, with gain of chromosome 7 in all but one of the remaining patients. Ninety-five percent of patients manifested EGFR amplification and/or polysomy of chromosome 7. Heterogeneity was found within a given tumor, with 10% to 60% of cells showing gain of chromosome 7. Overall patient survival was poor (mean, 4.6 months), but was significantly longer in those with EGFR gene amplification (mean, 8.3 months; median, 10.5 months) versus those without (mean, 3.2 months; median, 2.0 months) (P = .04). The presence of EGFR amplification is a significant predictor of survival time in older old patients.