EGFR polymorphism of the kinase domain in Japanese lung cancer

EGFR Q787Q Polymorphism Is a Germline Variant and a Prognostic Factor for Lung Cancer Treated With TKIs

The prevalence and impact of epidermal growth factor receptor (EGFR) Q787Q polymorphism on the treatment of lung adenocarcinoma remains unclear. We retrospectively analyzed patients with stage IV lung adenocarcinoma to evaluate the prevalence of the EGFR Q787Q polymorphism and its influence on effects of tyrosine kinase inhibitor (TKI) treatment. A total of 333 patients were included in this study. The prevalence of the EGFR Q787Q polymorphism was 38%, 42%, and 35% in the total patients, EGFR mutation negative, and EGFR mutation positive groups, respectively. The prevalence of EGFR Q787Q polymorphism was significantly higher in EGFR wild-type patients than in the general non-cancerous population from Taiwan Biobank and 1000 Genome Project databases, respectively. EGFR Q787Q polymorphism had significant protective effects on the overall survival of EGFR-mutant lung adenocarcinoma treated with EGFR TKIs (aHR =0.61, p=0.03). Our study demonstrated that EGFR Q787Q polymorphism is a germline variant in the general population. It is a protective predictor of overall survival in patients with stage IV EGFR-mutated lung adenocarcinoma treated with TKIs.

Genetic variant rs10251977 (G>A) in EGFR-AS1 modulates the expression of EGFR isoforms A and D

Tyrosine kinase inhibitor is an effective chemo-therapeutic drug against tumors with deregulated EGFR pathway. Recently, a genetic variant rs10251977 (G>A) in exon 20 of EGFR reported to act as a prognostic marker for HNSCC. Genotyping of this polymorphism in oral cancer patients showed a similar frequency in cases and controls. EGFR-AS1 expressed significantly high level in tumors and EGFR-A isoform expression showed significant positive correlation (r = 0.6464, p < 0.0001) with reference to EGFR-AS1 expression levels, consistent with larger TCGA HNSCC tumor dataset. Our bioinformatic analysis showed enrichment of alternative splicing marks H3K36me3 and presence of intronic polyA sites spanning around exon 15a and 15b of EGFR facilitates skipping of exon 15b, thereby promoting the splicing of EGFR-A isoform. In addition, high level expression of PTBP1 and its binding site in EGFR and EGFR-AS1 enhances the expression of EGFR-A isoform (r = 0.7404, p < 0.0001) suggesting that EGFR-AS1 expression modulates the EGFR-A and D isoforms through alternative splicing. In addition, this polymorphism creates a binding site for miR-891b in EGFR-AS1 and may negatively regulate the EGFR-A. Collectively, our results suggested the presence of genetic variant in EGFR-AS1 modulates the expression of EGFR-D and A isoforms.

GENETIC POLYMORPHISM OF RETROPERITONEAL MYXOID LIPOSARCOMA

Objective: to detect new molecular genetic markers and therapeutic targets in retroperitoneal myxoid liposarcoma.

Material and Methods. DNA samples isolated from tumor tissue and obtained from formalinfixed paraffin-embedded (FFPE) slides were used. DNA was extracted using the GeneRead DNA FFPE Kit (50) (Qiagen). High-throughput next generation sequencing (NGS) using the GeneReader Actionable Insights Tumor Panel (GRTP – 101X) on the QCI Analyzer version 1.1 platform (Qiagen) was used for molecular genetic analysis of 12 genes involved in carcinogenesis: KRAS, NRAS, KIT, BRAF, PDGFRA, ALK, EGFR, ERBB2, PIK3CA, ERBB3, ESR1, RAF1.

Results. Targeted sequencing of retroperitoneal extra-organ myxoid liposarcoma demonstrated genetic heterogeneity. Our study was the first to describe mutations and polymorphic variants in genes, such as EGFR, PIK3CA, ALK, BRAF, ERBB2 / 3, ESR1, KIT, PDGFRA in myxoid liposarcoma.

Conclusion. This study demonstrated a wide range of molecular genetic rearrangements in retroperitoneal extra-organ myxoid liposarcoma. Synonymous mutations in the EGFR (Q787Q) and PDGFRA (P567P) genes were detected in all cases (100 %). Missense mutations in the ERBB2 gene (P1170A) and synonymous mutations in the ALK (G845G) and BRAF genes were identified in 75 % of cases. Missense mutation in the PIK3CA gene (I391M) was detected in 25 % of cases. The gene polymorphisms presented in this paper are most likely involved in the carcinogenesis of retroperitoneal myxoid liposarcoma. Further studies with larger patient groups and multivariate analysis of long-term treatment results are required. 

Evaluation of epidermal growth factor receptor mutations and thyroid transcription factor-1 status in Turkish non-small cell lung carcinoma patients: A study of 600 cases from a single center

Background

This study aims to investigate the frequency, distribution, and morphological/immunohistochemical features of epidermal growth factor receptor mutations and to examine the possible relationship between the material type and technical success of mutation analysis in Turkish population with non-small cell lung cancer.

Methods

Between September 2012 and December 2015, a total of 499 consecutive, treatment-naïve patients (437 males, 163 females; mean age 61 years; range, 30 to 84 years) with primary or metastatic non-small cell lung cancer who underwent epidermal growth factor receptor mutation testing using Sanger sequencing method were retrospectively analyzed. Archival records and hematoxylin-eosine and immunohistochemically stained sections were re-examined. The thyroid transcription factor-1 and napsin A immunohistochemical stains were performed on tissue array blocks.

Results

Seventy-five mutations were detected in 70 patients (14%). The success rate of testing and intact deoxyribonucleic acid fragment length were significantly higher in the cytological material, compared to tissue specimens (p<0.001). The mutation rate in adenocarcinomas was 33.9% for women and 9.4% for men. The most common mutation was L746-E750del in exon 19 (29.3%), followed by the L858R mutation in exon 21 (28%). The mutation rate was the highest in micropapillary (40%) and lowest in solid (5.4%) adenocarcinomas. All epidermal growth factor receptor mutations, except for one, were positive for the thyroid transcription factor-1. The single nucleotide polymorphism Q787Q in exon 20 was observed in 79.6% of patients.

Conclusion

The frequency and distribution of epidermal growth factor receptor mutations in the Turkish patients with non-small cell lung cancer are similar to the European populations. These results also demonstrate that cytological materials are highly reliable for epidermal growth factor receptor mutation testing, and the probability of detection of wild-type epidermal growth factor receptor is low in cases of thyroid transcription factor-1 negativity.

Prevalence of EGFR Mutations in Lung Cancer in Uruguayan Population

BACKGROUND

Incorporation of molecular analysis of the epidermal growth factor receptor (EGFR) gene into routine clinical practice represents a milestone for personalized therapy of the non-small-cell lung cancer (NSCLC). However, the genetic testing of EGFR mutations has not yet become a routine clinical practice in developing countries. In view of different prevalence of such mutations among different ethnicities and geographic regions, as well as the limited existing data from Latin America, our aim was to study the frequency of major types of activating mutations of the EGFR gene in NSCLC patients from Uruguay.

METHODS

We examined EGFR mutations in exons 18 through 21 in 289 NSCLC Uruguayan patients by PCR-direct sequencing.

RESULTS

EGFR mutations were detected in 53 of the 289 (18.3%) patients, more frequently in women (23.4%) than in men (14.5%). The distribution by exon was similar to that generally reported in the literature.

CONCLUSIONS

This first epidemiological study of EGFR mutations in Uruguay reveals a wide spectrum of mutations and an overall prevalence of 18.3%. The background ethnic structure of the Uruguayan population could play an important role in explaining our findings.

Comparison of next generation sequencing, SNaPshot assay and real-time polymerase chain reaction for lung adenocarcinoma EGFR mutation assessment

BACKGROUND

The epidermal growth factor receptor (EGFR) mutation status assessment has become increasingly important given the significant impact of tyrosine kinase inhibitors in lung cancer management. Our aim was to compare real life operational characteristics for three EGFR mutation assays - two targeted approaches and a next generation sequencing (NGS) technique.

METHODS

EGFR mutation status was assessed for lung adenocarcinoma samples (formalin fixed- paraffin embedded samples) using qPCR, SNaPshot and NGS (Ion Torrent™) techniques.

RESULTS

A total of 15 high clinical significance mutations were identified by at least one technique from the total of 64 samples. All mutations were identified by the TaqMan qPCR technique while SNaPshot in conjunction with fragment analysis identified 11 EGFR mutations. The NGS approach followed by an automatic analysis using the default calling parameters identified 10 mutations from the SNaPshot/qPCR panel and other three insertions, five point mutations and 58 silent variants; manual data review identified all 15 high significance mutations.

CONCLUSIONS

Performance was similar for high tumor content samples but careful data analysis and post hoc variant calling filter alterations were necessary in order to obtain robust results from low tumor content samples by NGS. NGS is able to generate a comprehensive mutational profile albeit at a higher cost and workload. Result interpretation should take into account not only general run parameters such as mean read depth but also relative coverage and read distribution; currently there is an acute need to define firm recommendations/standards concerning NGS data interpretation and quality control.

A synonymous EGFR polymorphism predicting responsiveness to anti-EGFR therapy in metastatic colorectal cancer patients

Genetic factors are known to affect the efficiency of therapy with monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor (EGFR) in patients with metastatic colorectal cancer (mCRC). At present, the only accepted molecular marker predictive of the response to anti-EGFR mAbs is the somatic mutation of KRAS and NRAS as a marker of resistance to anti-EGFR. However, only a fraction of KRAS wild-type patients benefit from that treatment. In this study, we show that the EGFR gene polymorphism rs1050171 defines, independently of RAS mutational status, a sub-population of 11 % of patients with a better clinical outcome after anti-EGFR treatment. Median PFS for patients with the GG genotype was 10.17 months compared to 5.37 of those with AG + AA genotypes. Taken together, our findings could be used to better define CRC populations responding to anti-EGFR therapy. Further studies in larger independent cohorts are necessary to validate the present observation that a synonymous polymorphism in EGFR gene impacts on clinical responsiveness.

Clinical characteristics, tumor, node, metastasis status, and mutation rate in domain of epidermal growth factor receptor gene in serbian patients with lung adenocarcinoma

OBJECTIVE

Mutation rate in domain of EGFR gene varies between populations of lung cancer patients. Primary aim of this study was to analyze clinical and pathological characteristics, and tumor, node, metastasis status and stage of diseases, in relation to mutation status.

METHODS

After histological confirmation of lung adenocarcinoma tissue obtained during bronchoscopy was consecutively sent for EGFR testing. Genomic DNA extraction was performed with the QIAamp DNA FFPE Tissue kit. Clinical data for multivariate analysis were extracted from hospital based-lung cancer registry.

RESULTS

Among 360 tested patients, there was 67.8% males and 32.2% females, aged 61 ± 9.8 years. Majority of patients were smokers (57.0%) with Eastern Cooperative Oncology Group 1 performance status (92.2%). Mutation in EGFR gene was detected in 42 (11.7%) patients. Deletion in exon 19 was detected in 24 (6.7%) patients, mutation in exon 21 in 17 (4.7%), and mutation in exon 18 in one patient (0.3%). Patients were mostly diagnosed in stage IV adenocarcinoma (74.4%). Statistically significant differences were determined in relation to smoking (p < 0.001), T descriptor (size; p = 0.019) and gender (p = 0.002).

CONCLUSIONS

Mutation rate in domain of EGFR gene in investigated lung cancer population is in range with reported data in Caucasian race. Smoking, T descriptor and gender were found to be related to the EGFR status.

Profiling of phospho-AKT, phospho-mTOR, phospho-MAPK and EGFR in non-small cell lung cancer

Activation of numerous pathways has been documented in non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) has emerged as a common therapeutic target. The mitogen-activated protein kinase (MAPK) and AKT signaling pathways are downstream of EGFR and deregulated via genetic and epigenetic mechanisms in many human cancers. We evaluated selected markers in the EGFR pathway with reference to outcome. Tissues from 220 cases of NSCLC patients presented in a tissue microarray were assayed with immunohistochemistry for phosphorylated AKT, phosphorylated MAPK, phosphorylated mTOR, and EGFR and then quantified by automated image analysis. Individually, the biomarkers did not predict. Combined as ratios, p-mTOR/p-AKT, and p-MAPK/EGFR function as prognostic markers of survival (p=0.008 and p=0.029, respectively), however, no significance was found after adjustment (p=0.221, p=0.103). The sum of these ratios demonstrates a stronger correlation with survival (p<0.001) and remained statistically significant after adjustment (p=0.026). The algebraic combination of biomarkers offer the capacity to understand factors that predict outcome better than current approaches of evaluating biomarkers individually or in pairs. Our results show the sum of p-mTOR/p-AKT and p-MAPK/EGFR is a potential predictive marker of survival in NSCLC patients.

Patients with peritoneal mesothelioma lack epidermal growth factor receptor tyrosine kinase mutations that would make them sensitive to tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) is a promising target for cancer therapy. The presence of certain somatic mutations in the tyrosine kinase (TK) domain of the EGFR gene is associated with clinical response to TK inhibitors (TKI) in patients with lung adenocarcinoma. In this study we evaluated the status of somatic mutations in the entire TK domain of the EGFR gene by direct sequencing using early passage peritoneal mesothelioma cells, established cell lines as well as 33 peritoneal mesothelioma tumor samples. No novel mutations were found in the cell lines. Sequence analysis of the EGFR TK domain revealed the presence of a silent polymorphism (c.2607G → A, Q787Q) at exon 20 of both peritoneal mesothelioma cell lines as well as tumor specimens. The frequency of genotypes AA and GA was 42.8 and 57.2% in the cell lines and 33.3 and 57.6% in tumor specimens, respectively. The TKI erlotinib showed an IC50 in the range of 10-50 µM in five out of the seven cell lines with a GA genotype while all five cell lines with the AA genotype had an IC50 >50 µM. Of the 33 peritoneal mesothelioma tumor samples analyzed none had an EGFR TKI sensitizing mutation and only one specimen showed an earlier reported somatic mutation at codon 850 in exon 21 of the EGFR gene. Our data show that patients with peritoneal mesothelioma do not harbor somatic mutations in the EGFR TK domain that would make them sensitive to EGFR TKI.

EGFR and KRAS mutations in Chinese patients with adenosquamous carcinoma of the lung

Adenosquamous carcinoma (ADSQ) is uncommon in non-small cell lung cancer (NSCLC). The frequency rate of ADSQ was 9.7% of 6990 primary lung cancers resected in our department. Many researches have analyzed genetic and molecular alterations in adenocarcinoma (AD) and squamous cell carcinoma (SQ), but few molecular studies have been conducted on heterogeneous ADSQ. The current study was to investigate gene mutations of epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma viral oncogene (KRAS) and their correlation with clinical variables in Chinese patients with ADSQ. Histologic features were reviewed, and immunohistochemical (IHC) and molecular (EGFR and KRAS) studies were done in 55 Chinese patients with ADSQ. Microscopically, all the tumors demonstrated dual differentiation with varying proportions of AD and SQ. Based on morphological diagnosis, a combination of multiple IHC markers is helpful for accurately discriminating two undifferentiated histologic subtypes of ADSQ. EGFR mutations were identified in 21 (38.2%) patients: 11 mutations were in exon 19, 1 in exon 20, 7 in exon 21 and double mutations were found in two patients. We also found two new mutations, namely, L747-E749del K754A within exon 19 and H850R within exon 21. Moreover, 16 (29.1%) silent mutations Q787Q in exon 20 were found in the series, five of which coexisted with other mutations. EGFR mutations were more frequently found in patients with size of the tumors ≥3cm [19/35 (54.3%); 2/20 (10%); P=0.001] or coexistent double cancer. However, the EGFR mutation was not associated with gender, age, lymph node status, tumor stage and smoking history. KRAS mutations were present in 2 (3.64%) male patients in codon12 (G12C) and none of them showed EGFR mutation. Moreover, identical EGFR and KRAS mutations in both components of ADSQ were further confirmed by microdissection techniques. The data indicated that the incidence of EGFR and KRAS mutations in Chinese patients with ADSQ were similar to those of Asian patients with AD. Furthermore, EGFR silent mutations accounted for a large proportion in ADSQ. Additional prospective studies are needed in order to define the clinical relevance of new and silent mutation variants.