Assessment of epidermal growth factor receptor and K-ras mutation status in cytological stained smears of non-small cell lung cancer patients: correlation with clinical outcomes

Objective.

Epidermal growth factor receptor (EGFR) and K-ras mutations guide treatment selection in non-small cell lung cancer (NSCLC) patients. Although mutation status is routinely assessed in biopsies, cytological specimens are frequently the only samples available. We determined EGFR and K-ras mutations in cytological samples.

Methods.

DNA was extracted from 150 consecutive samples, including 120 Papanicolau smears (80%), 10 cell blocks (7%), nine fresh samples (6%), six ThinPrep® tests (4%), and five body cavity fluids (3.3%). Papanicolau smears were analyzed when they had >50% malignant cells. Polymerase chain reaction and direct sequencing of exons 18–21 of EGFR and exon 2 of K-ras were performed. EGFR mutations were simultaneously determined in biopsies and cytological samples from 20 patients. Activity of EGFR tyrosine kinase inhibitors (TKIs) was assessed.

Results.

The cytological diagnosis was adenocarcinoma in 110 samples (73%) and nonadenocarcinoma in 40 (27%) samples. EGFR mutations were identified in 26 samples (17%) and K-ras mutations were identified in 18 (12%) samples. EGFR and K-ras mutations were mutually exclusive. In EGFR-mutated cases, DNA was obtained from stained smears in 24 cases (92%), pleural fluid in one case (4%), and cell block in one case (4%). The response rate to EGFR TKIs in patients harboring mutations was 75%. The mutation status was identical in patients who had both biopsies and cytological samples analyzed.

Conclusion.

Assessment of EGFR and K-ras mutations in cytological samples is feasible and comparable with biopsy results, making individualized treatment selection possible for NSCLC patients from whom tumor biopsies are not available.     

Coexistence of EGFR with KRAS,or BRAF,or PIK3CA somatic mutations in lung cancer: a comprehensive mutation profiling from 5125 Chinese cohorts

Background:

Determining the somatic mutations of epidermal growth factor receptor (EGFR)-pathway networks is the key to effective treatment for non-small cell lung cancer (NSCLC) with tyrosine kinase inhibitors (TKIs).The somatic mutation frequencies and their association with gender, smoking history and histology was analysed and reported in this study.

Methods:

Five thousand one hundred and twenty-five NSCLC patients'' pathology samples were collected, and EGFR, KRAS, BRAF and PIK3CA mutations were detected by multiplex testing. The mutation status of EGFR, KRAS, BRAF and PIK3CA and their association with gender, age, smoking history and histological type were evaluated by appropriate statistical analysis.

Results:

EGFR, KRAS, BRAF and PIK3CA mutation rates revealed 36.2%, 8.4%, 0.5% and 3.3%, respectively, across the 5125 pathology samples. For the first time, evidence of KRAS mutations were detected in two female, non-smoking patients, age 5 and 14, with NSCLC. Furthermore, we identified 153 double and coexisting mutations and 7 triple mutations. Interestingly, the second drug-resistant mutations, T790M or E545K, were found in 44 samples from patients who had never received TKI treatments.

Conclusions:

EGFR exons 19, 20 and 21, and BRAF mutations tend to happen in females and non-smokers, whereas KRAS mutations were more inclined to males and smokers. Activating and resistant mutations to EGFR-TKI drugs can coexist and ‘second drug-resistant mutations'', T790M or E545K, may be primary mutations in some patients. These results will help oncologists to decide candidates for mutation testing and EGFR-TKI treatment.     

EGFR mutation heterogeneity and the mixed response to EGFR tyrosine kinase inhibitors of lung adenocarcinomas

Background.

Non-small cell lung cancer patients with epidermal growth factor receptor (EGFR) mutations have mixed responses to tyrosine kinase inhibitors (TKIs). Intertumor heterogeneity in EGFR mutations is one potential explanation for this phenomenon.

Methods.

We performed direct sequencing to identify EGFR mutations in 180 pairs of lung adenocarcinoma samples (from 3,071 patients). The high-resolution melting method was used in discordant cases to confirm EGFR mutation status. Matching samples were divided into four groups: primary lesions detected at different times, primary tumors with matched metastatic lymph nodes, multiple pulmonary nodules, and primary tumors with matched distant metastases. Multivariate analyses were performed to evaluate correlations between heterogeneity and patient characteristics.

Results.

In the study population, the discordance rate was 13.9% (25 of 180). The multiple pulmonary nodules group had the highest discordance rate of 24.4% (10 of 41; odds ratio for heterogeneity in primary lesions detected at different times, 6.37; 95% confidence interval, 1.71–23.72; p = .006). Discordance rates in the metachronous and synchronous settings were 15.7% (22 of 140) and 7.5% (three of 40), respectively. In the 34 patients who developed EGFR TKI resistance, 10 (29.4%) cases exhibited heterogeneity and five (14.7%) patients exhibited a mixed response to the drug. Three (8.8%) of the patients with a mixed response also exhibited discordant EGFR mutations.

Conclusions.

The overall discordance rate of EGFR mutation heterogeneity in Asian patients with pulmonary adenocarcinoma is relatively low, but the rate in patients with multiple pulmonary nodules is significantly higher. This observation may explain the mixed tumor response to EGFR TKIs.     

Clinicopathological and prognostic significance of interleukin-8 expression and its relationship to KRAS mutation in lung adenocarcinoma

Background:

On the basis of our recent findings of oncogenic KRAS-induced interleukin-8 (IL-8) overexpression in non-small cell lung cancer, we assessed the clinicopathological and prognostic significances of IL-8 expression and its relationship to KRAS mutations in lung adenocarcinomas.

Methods:

IL-8 expression was examined by quantitative RT–PCR using 136 of surgical specimens from lung adenocarcinoma patients. The association between IL-8 expression, clinicopathological features, KRAS or EGFR mutation status and survival was analysed.

Results:

IL-8 was highly expressed in tumours from elderly patients or smokers and in tumours with pleural involvement or vascular invasion. In a non-smokers'' subgroup, IL-8 level positively correlated with age. IL-8 was highly expressed in tumours with KRAS mutations compared with those with EGFR mutations or wild-type EGFR/KRAS. Lung adenocarcinoma patients with high IL-8 showed significantly shorter disease-free survival (DFS) and overall survival (OS) than those with low IL8. DFS and OS were significantly shorter in the patients with mutant KRAS/high IL-8 than in those with wild-type KRAS/low IL-8. Cox regression analyses demonstrated that elevated IL-8 expression correlated with unfavourable prognosis.

Conclusions:

Our findings suggest that IL-8 expression is associated with certain clinicopathological features including age and is a potent prognostic marker in lung adenocarcinoma, especially in oncogenic KRAS-driven adenocarcinoma.     

Picoliter‐Droplet Digital Polymerase Chain Reaction‐Based Analysis of Cell‐Free Plasma DNA to Assess EGFR Mutations in Lung Adenocarcinoma That Confer Resistance to Tyrosine‐Kinase Inhibitors

Purpose.

The objective of this study was to evaluate the utility of analyzing cell-free plasma DNA (cfDNA) by picoliter-droplet digital polymerase chain reaction (ddPCR) to detect EGFR mutations that confer resistance to tyrosine-kinase inhibitors (TKIs) used for treatment of lung adenocarcinoma (LADC).

Experimental design.

Thirty-five LADC patients who received epidermal growth factor receptor (EGFR)-TKI therapy, including ten who received tumor rebiopsy after development of resistance, were subjected to picoliter-ddPCR-cfDNA analysis to determine the fraction of cfDNA with TKI-sensitive (L858R and inflame exon 19 deletions) and -resistant (i.e., T790M) mutations, as well as their concordance with mutation status in rebiopsied tumor tissues.

Results.

cfDNA samples from 15 (94%) of 16 patients who acquired resistance were positive for TKI-sensitive mutations. Also, 7 (44%) were positive for the T790M mutation, with fractions of T790M (+) cfDNA ranging from 7.4% to 97%. T790M positivity in cfDNA was consistent in eight of ten patients for whom rebiopsied tumor tissues were analyzed, whereas the remaining cases were negative in cfDNA and positive in rebiopsied tumors. Prior to EGFR-TKI therapy, cfDNAs from 9 (38%) and 0 of 24 patients were positive for TKI-sensitive and T790M mutations, respectively. Next-generation sequencing of cfDNA from one patient who exhibited innate resistance to TKI despite a high fraction of TKI-sensitive mutations and the absence of the T790M mutation in his cfDNA revealed the presence of the L747P mutation, a known driver of TKI resistance.

Conclusion.

Picoliter-ddPCR examination of cfDNA, supported by next-generation sequencing analysis, enables noninvasive assessment of EGFR mutations that confer resistance to TKIs.

Implications for Practice:

Noninvasive monitoring of the predominance of tumors harboring the secondary T790M mutation in the activating mutation in EGFR gene is necessary for precise and effective treatment of lung adenocarcinoma. Because cells harboring the T790M mutation are resistant to epidermal growth factor receptor-tyrosine-kinase inhibitors (TKIs), the predominance of tumor cells harboring the T790M mutations influences the choice of whether to use conventional or next-generation TKIs. Digital polymerase chain reaction-based examination of cfDNA is a promising method; however, its feasibility, including its consistency with examination of rebiopsied tumor tissue, has not been fully proven. Here, picoliter-droplet digital polymerase chain reaction technology is presented as a candidate method for testing cfDNA and assessing the predominance of T790M-mutant tumors.     

Revisiting Clinical Trials Using EGFR Inhibitor-Based Regimens in Patients with Advanced Non-Small Cell Lung Cancer: A Retrospective Analysis of an MD Anderson Cancer Center Phase I Population

Purpose

Single-agent EGFR inhibitor therapy is effective mainly in patients with lung cancer and EGFR mutations. Treating patients who develop resistance, or who are insensitive from the outset, often because of resistant mutations, other aberrations or the lack of an EGFR mutation, probably requires rational combinations. We therefore investigated the outcome of EGFR inhibitor-based combination regimens in patients with heavily-pretreated non-small cell lung cancer (NSCLC) referred to a Phase I Clinic.

Methods

We reviewed the electronic records of patients with NSCLC treated with an EGFR inhibitor-based combination regimen: erlotinib and cetuximab; erlotinib, cetuximab and bevacizumab; erlotinib and dasatinib; erlotinib and bortezomib; or cetuximab and sirolimus.

Results

EGFR mutations were detected in 16% of patients (21/131). EGFR inhibitor-based combination regimens were administered to 15 patients with EGFR-mutant NSCLC and 24 with EGFR wild-type disease. Stable disease (SD) ≥6 months/partial remission (PR) was attained in 20% of EGFR-mutant patients (3/15; two with sensitive mutations and secondary resistance to prior erlotinib, and one with a resistant mutation), as well as 26% of evaluable patients (5/19) with wild-type disease. One of three evaluable patients with squamous cell histology achieved SD for 26.5 months (EGFR wild-type, TP53-mutant, regimen=erlotinib, cetuximab and bevacizumab).

Conclusions

Eight of 34 evaluable patients (24%) with advanced, refractory NSCLC evaluable for response achieved SD ≥6 months/PR (PR=3; SD ≥6 months=5) on EGFR inhibitor-based combination regimens (erlotinib, cetuximab; erlotinib, cetuximab and bevacizumab; and, erlotinib, bortezomib), including patients with secondary resistance to single-agent EGFR inhibitors, resistant mutations, wild-type disease, and, squamous histology.     

PIK3CA mutation in Chinese patients with lung squamous cell carcinoma

Objective

To investigate PIK3CA mutation in Chinese patients with lung squamous cell carcinoma (LSCC) and explore their relationship with clinicopathological profiles.

Methods

Tumor samples from 123 cases of LSCC were included in this study. PIK3CA mutations in exon 9 and 20 were screened by pyrosequencing and confirmed by clone sequencing or amplification refractory mutation system (ARMS). Denaturing performance liquid chromatography (DHPLC) was employed for evaluation of EGFR mutation in exon 19, 21 and KRAS mutation.

Results

PIK3CA mutations were found in 3 (2.4%) patients. The mutation type included E545K, E452Q and H1047R. Of these three patients, one coupled with EGFR mutation, and the other two coupled with PIK3CA amplification. All the three patients shared the same clinicopathologic characteristics: male, less than 60 years old, had smoke history, stage III and carried wild-type KRAS.

Conclusions

The frequency of PIK3CA mutation is low in Chinese patients with LSCC. The mutational status of PIK3CA is not mutually exclusive to EGFR mutation.Key Words: Lung squamous cell carcinoma (LSCC), PIK3CA mutation, EGFR mutation, KRAS mutation     

EGFR gene amplification is related to adverse clinical outcomes in cervical squamous cell carcinoma, making the EGFR pathway a novel therapeutic target

Background:

The aim of this study was to investigate the patterns of epidermal growth factor receptor (EGFR) overexpression, EGFR gene amplification, and the presence of activating mutations in the tyrosine kinase domain of this gene in squamous cell carcinomas and adenocarcinomas/adenosquamous carcinomas of the uterine cervix.

Methods:

The EGFR expression, amplification, and mutation in cervical carcinomas were assessed by immunohistochemistry, fluorescence in situ hybridisation, and PCR–SSCP, respectively, and correlated with clinical data collected by a retrospective chart review. A functional assessment was performed by inactivating EGFR in cervical cancer cells with the potent inhibitor AG1478.

Results:

Immunohistochemical analysis revealed that 6 out of 59 (10.2%) cervical squamous cell carcinomas showed significant amplification of the EGFR locus, whereas none of the 52 adeno/adenosquamous cell carcinomas had detectable EGFR amplification (P<0.05). The EGFR amplification significantly correlated with shorter overall survival (P=0.001) in cervical squamous cell carcinomas. Multivariate analysis showed that EGFR gene amplification was an independent prognostic factor for overall survival (P=0.011). None of the squamous cell carcinomas (0%: 0 out of 32) had detectable oncogenic mutations in EGFR exons 18 through 21. The frequencies of KRAS and BRAF mutations were very low in both squamous and adeno/adenosquamous cell carcinomas. Sensitivity of cervical cancer cells to AG1478 depended on the presence of EGFR overexpression. AG1478-induced EGFR inactivation in cell lines with EGFR overexpression significantly suppressed tumour development and progression in a mouse xenograft model.

Conclusion:

Our data suggest that EGFR signalling is important in a subset of cervical squamous cell carcinomas and that anti-EGFR therapy may benefit patients who carry the 7p11.2 amplicon in their tumours.     

Molecular predictors of response to tyrosine kinase inhibitors in patients with Non-Small-Cell Lung Cancer

Introduction

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have become a treatment option in non-small-cell lung cancer (NSCLC) patients. However, despite their use in this disease, a significant number of patients will eventually develop resistance and relapse. In this study, we aimed to characterize several molecular events involved in potential resistance mechanisms to anti-EGFR treatment and correlate our findings with clinical outcome.

Material and methods

The medical records of patients with NSCLC who received anti-EGFR TKIs in any line within the participating centers were reviewed and available paraffin embedded tissue was retrieved. Mutational analysis for EGFR, KRAS, BRAF and intron-exon 14 deletions of MET; FISH analysis for chromosomal gain or amplification for EGFR, MET and the deletion marker D7S486 were performed. Furthermore, the expression of EGFR and MET were analysed by immunohistochemistry. All results were correlated with treatment outcomes.

Results

Between 10/2001 and 12/2009 from an initial cohort of 72 treated patients, 59 cases (28 gefitinib/ 31 erlotinib) were included in the analysis. The majority had adenocarcinoma histology (68%), and received treatment in the second line setting (56%). Disease control rate (DCR) was 25.4% for all patients. EGFR and RAS mutational rates were 33% and 10% respectively, no other mutations were identified. High EGFR expressing tumors were found in 7 of 45 cases and pEGFR positivity (IHC) was found in 56% of the cases; MET expression was found in 48% of tumors. EGFR gene amplification was found in 4 cases, two cases showed high polysomy; overall, 13% cases were FISH positive for EGFR. High polysomy of MET gene was detected in 1/43 cases tested. D7S486 locus deletion was detected in 15/37 (40%) of cases. EGFR mutational status and gene gain were both associated with more favorable DCR. No other associations between examined biomarkers and DCR or survival were noted.

Conclusions

EGFR mutational status is a predictor for disease control in patients with NSCLC treated with anti-EGFR TKIs. The predictive role of several other molecules involved in potential resistance to anti-EGFR TKIs is worthy of additional investigation.     

PD-1 and PD-L1 expression in molecularly selected non-small-cell lung cancer patients

Background:

Agents targeting programmed death-1 receptor (PD-1) and its ligand (PD-L1) are showing promising results in non-small-cell lung cancer (NSCLC). It is unknown whether PD-1/PD-L1 are differently expressed in oncogene-addicted NSCLC.

Methods:

We analysed a cohort of 125 NSCLC patients, including 56 EGFR mutated, 29 KRAS mutated, 10 ALK translocated and 30 EGFR/KRAS/ALK wild type. PD-L1 and PD-1 expression were assessed by immunohistochemistry. All cases with moderate or strong staining (2+/3+) in >5% of tumour cells were considered as positive.

Results:

PD-1 positive (+) was significantly associated with current smoking status (P=0.02) and with the presence of KRAS mutations (P=0.006), whereas PD-L1+ was significantly associated to adenocarcinoma histology (P=0.005) and with presence of EGFR mutations (P=0.001). In patients treated with EGFR tyrosine kinase inhibitors (N=95), sensitivity to gefitinib or erlotinib was higher in PD-L1+ vs PD-L1 negative in terms of the response rate (RR: P=0.01) time to progression (TTP: P<0.0001) and survival (OS: P=0.09), with no difference in PD1+ vs PD-1 negative. In the subset of 54 EGFR mutated patients, TTP was significantly longer in PD-L1+ than in PD-L1 negative (P=0.01).

Conclusions:

PD-1 and PD-L1 are differentially expressed in oncogene-addicted NSCLC supporting further investigation of specific checkpoint inhibitors in combination with targeted therapies.     

Mutation analysis of the EGFR gene and downstream signalling pathway in histologic samples of malignant pleural mesothelioma

Background:

As epidermal growth factor receptor (EGFR) is involved in the pathogenesis of malignant pleural mesotheliomas (MPMs), the anti-EGFR drugs may be effective in treating MPM patients. Mutations of the EGFR gene or its downstream effectors may cause constitutive activation leading to cell proliferation, and the inhibition of apoptosis and metastases. Consequently, molecular profiling is essential for select patients with MPM who may respond to anti-EGFR therapies.

Methods:

After manual macrodissection, genomic DNA was extracted from 77 histological samples of MPM: 59 epithelioid, 10 biphasic, and 8 sarcomatoid. Epidermal growth factor receptor gene mutations were sought by means of real-time polymerase chain reaction (PCR) and direct sequencing, KRAS gene mutations by mutant-enriched PCR, and PIK3CA and BRAF gene mutations by direct sequencing.

Results:

Gene mutations were identified in nine cases (12%): five KRAS, three BRAF, and one PI3KCA mutation; no EGFR gene mutations were detected. There was no difference in disease-specific survival between the patients with or without gene mutations (P=0.552).

Conclusions:

Mutations in EGFR downstream pathways are not rare in MPM. Although none of those found in this study seemed to be prognostically significant, they may support a more specific selection of patients for future trials.     

Low EGFR/MET ratio is associated with resistance to EGFR inhibitors in non-small cell lung cancer

Purpose

Although activating mutations in the epidermal growth factor receptor (EGFR) gene are predictive markers for response to EGFR inhibitors, 30–40% of EGFR-mutant non-small cell lung cancer (NSCLC) patients are de novo non-responders. Hence, we sought to explore additional biomarkers of response.

Methods

We conducted a prospective pilot study to characterize the expression and/or activation of key receptor tyrosine kinases (RTKs) in stage IIIB-IV NSCLC tumors. A total of 37 patients were enrolled and 34 underwent EGFR inhibitor treatment.

Results

As expected, patients bearing activating EGFR mutations showed increased progression free survival (PFS) compared to patients with wild-type EGFR status (9.3 vs 1.4 months, p = 0.0629). Analysis of baseline tumor RTK profiles revealed that, regardless of EGFR mutation status, higher levels of EGFR relative to MET correlated with longer PFS. At multiple EGFR/MET ratio cut-offs, including 1, 2 and 3, median PFS according to below vs. above cut-offs were 0.4 vs. 6.1 (p = 0.0001), 0.5 vs. 9.3 (p = 0.0006) and 1.0 vs. 11.2 months (p = 0.0008), respectively.

Conclusion

The EGFR/MET ratio measured in tumors at baseline may help identify NSCLC patients most likely to benefit from prolonged PFS when treated with EGFR inhibitors.     

Experience With Afatinib in Patients With Non‐Small Cell Lung Cancer Progressing After Clinical Benefit From Gefitinib and Erlotinib

Background.

Afatinib, an irreversible ErbB family blocker, demonstrated superiority to chemotherapy as first-line treatment in patients with EGFR-mutated non-small cell lung cancer (NSCLC). Afatinib is also active in patients progressing on EGFR tyrosine kinase inhibitors (EGFR-TKIs). We report the results of a large cohort of NSCLC patients receiving afatinib within a compassionate-use program (CUP).

Patients and Methods.

Patients with advanced NSCLC progressing after one line or more of chemotherapy and one line or more of EGFR-TKI treatment with either an EGFR mutation or documented clinical benefit were enrolled. Data collection was not monitored or verified by central review. The intention of this CUP was to provide controlled preregistration access to afatinib for patients with life-threatening diseases and no other treatment option.

Results.

From May 2010 to October 2013, 573 patients (65% female; median age: 64 years [range: 28–89 years]) were enrolled, with strong participation of community oncologists. Comorbidities were allowed, including second malignancies in 11% of patients. EGFR mutation status was available in 391 patients (72%), and 83% tested mutation positive. Median time to treatment failure (TTF) of 541 patients treated with afatinib was 3.7 months (range: 0.0 to >29.0 months). Median TTF was 4.0 and 2.7 months in patients with adenocarcinomas and squamous cell carcinomas, respectively, and 4.6 months in patients with EGFR-mutated NSCLC. Adverse events were generally manageable.

Conclusion.

Afatinib was able to be given in a real-world setting to heavily pretreated patients with EGFR-mutated or EGFR-TKI-sensitive NSCLC. Acknowledging the constraints of data collection in a CUP, afatinib appears to be safe and to confer some clinical benefit in this population.     

Detection of EGFR mutations in circulating free DNA by PNA-mediated PCR clamping

Background

Epidermal growth factor receptor (EGFR)-activating mutations are major determinants in predicting the tumor response to EGFR tyrosine kinase inhibitors in non-small cell lung cancer (NSCLC). Noninvasive test for the detection of EGFR mutations is required, especially in NSCLC patients from whom tissue is not available. In this study, we assessed the feasibility of detection of EGFR mutations in free DNA circulating in plasma.

Methods

Plasma samples of 60 patients with partial response to gefitinib were analyzed to detect EGFR-activating mutations in exons 19 and 21. Forty (66.7%) of patients had tumor EGFR mutation results. EGFR mutations in plasma were detected using the peptide nucleic acid (PNA)-mediated polymerase chain reaction (PCR) clamping method. All clinical data and plasma samples were obtained from 11 centers of the Korean Molecular Lung Cancer Group (KMLCG).

Results

Of the 60 patients, 39 were female and the median age was 62.5 years. Forty-three patients never smoked, 53 had adenocarcinomas, and seven had other histologic types. EGFR-activating mutation was detected in plasma of 10 cases (exon 19 deletion in seven and exon 21 L858R point mutation in three). It could not be found in plasma after treatment for 2 months. When only patients with confirmed EGFR mutation in tumor were analyzed, 17% (6 of 35) of them showed positive plasma EGFR mutation and the mutation type was completely matched with that in tumor. There was no statistically significant difference in clinical parameters between patients with EGFR mutations in plasma and those without EGFR mutations.

Conclusions

The detection rate of EGFR mutations from plasma was not so high despite highly sensitive EGFR mutation test suggesting that more advances in detection methods and further exploration of characteristics of circulating free DNA are required.     

Outcomes of First-Generation EGFR-TKIs Against Non-Small-Cell Lung Cancer Harboring Uncommon EGFR Mutations: A Post Hoc Analysis of the BE-POSITIVE Study

Background

Beyond progression after tyrosine kinase inhibitor in EGFR-positive non-small-cell lung cancer patients (BE-POSITIVE) was the first Italian multicenter observational study that reported the outcomes of first-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in a “real-life” Caucasian EGFR-mutated non-small-cell lung cancer (NSCLC) population. The sharing of multi-institutional experiences represents a crucial strategy to enrich knowledge about uncommon EGFR mutations. Therefore, we performed a post hoc analysis of the BE-POSITIVE study.

Epidermal growth factor receptor mutation analysis in cytological specimens and responsiveness to gefitinib in advanced non-small cell lung cancer patients

Background

Epidermal growth factor receptor (EGFR) mutation is the key predictor of EGFR tyrosine kinase inhibitors (TKIs) efficacy in non-small cell lung cancer (NSCLC). We conducted this study to verify the feasibility of EGFR mutation analysis in cytological specimens and investigate the responsiveness to gefitinib treatment in patients carrying EGFR mutations.

Methods

A total of 210 cytological specimens were collected for EGFR mutation detection by both direct sequencing and amplification refractory mutation system (ARMS). We analyzed EGFR mutation status by both methods and evaluated the responsiveness to gefitinib treatment in patients harboring EGFR mutations by overall response rate (ORR), disease control rate (DCR) and progression free survival (PFS).

Results

Of all patients, EGFR mutation rate was 28.6% (60/210) by direct sequencing and 45.2% (95/210) by ARMS (P<0.001) respectively. Among the EGFR wild type patients tested by direct sequencing, 26.7% of them were positive by ARMS. For the 72 EGFR mutation positive patients treated with gefitinib, the ORR, DCR and median PFS were 69.4%, 90.2% and 9.3 months respectively. The patients whose EGFR mutation status was negative by direct sequencing but positive by ARMS had lower ORR (48.0% vs. 80.9%, P=0.004) and shorter median PFS (7.4 vs. 10.5 months, P=0.009) as compared with that of EGFR mutation positive patients by both detection methods.

Conclusions

Our study verified the feasibility of EGFR analysis in cytological specimens in advanced NSCLC. ARMS is more sensitive than direct sequencing in EGFR mutation detection. EGFR Mutation status tested on cytological samples is applicable for predicting the response to gefitinib. Abundance of EGFR mutations might have an influence on TKIs efficacy.     

Activating GNAS and KRAS mutations in gastric foveolar metaplasia,gastric heterotopia,and adenocarcinoma of the duodenum

Background:

Heterotopic gastric-type epithelium, including gastric foveolar metaplasia (GFM) and gastric heterotopia (GH), is a common finding in duodenal biopsy specimens; however, there is still controversy regarding their histogenetic backgrounds.

Methods:

We analysed a total of 177 duodenal lesions, including 66 GFM lesions, 81 GH lesions, and 30 adenocarcinomas, for the presence of GNAS, KRAS, and BRAF mutations.

Results:

Activating GNAS mutations were identified in 27 GFM lesions (41%) and 23 GH lesions (28%). The KRAS mutations were found in 17 GFM lesions (26%) and 2 GH lesions (2%). A BRAF mutation was found in only one GFM lesion (2%). These mutations were absent in all 32 normal duodenal mucosa specimens that were examined, suggesting a somatic nature. Among the GFM lesions, GNAS mutations were more common in lesions without active inflammation. Analyses of adenocarcinomas identified GNAS and KRAS mutations in 5 (17%) and 11 lesions (37%), respectively. Immunohistochemically, all the GNAS-mutated adenocarcinomas diffusely expressed MUC5AC, indicating gastric epithelial differentiation.

Conclusions:

A significant proportion of GFM and GH harbours GNAS and/or KRAS mutations. The common presence of these mutations in duodenal adenoma and adenocarcinoma with a gastric epithelial phenotype implies that GFM and GH might be precursors of these tumours.     

EGFR gene copy number assessment from areas with highest EGFR expression predicts response to anti-EGFR therapy in colorectal cancer

Background:

Only 40–70% of metastatic colorectal cancers (mCRCs) with wild-type (WT) KRAS oncogene respond to anti-epidermal growth factor receptor (anti-EGFR) antibody treatment. EGFR amplification has been suggested as an additional marker to predict the response. However, improved methods for bringing the EGFR analysis into routine laboratory are needed.

Methods:

The material consisted of 80 patients with mCRC, 54 of them receiving anti-EGFR therapy. EGFR gene copy number (GCN) was analysed by automated silver in situ hybridisation (SISH). Immunohistochemical EGFR protein analysis was used to guide SISH assessment.

Results:

Clinical benefit was seen in 73% of high (⩾4.0) EGFR GCN patients, in comparison with 59% of KRAS WT patients. Only 20% of low EGFR GCN patients responded to therapy. A high EGFR GCN number associated with longer progression-free survival (P<0.0001) and overall survival (P=0.004). Together with KRAS analysis, EGFR GCN identified the responsive patients to anti-EGFR therapy more accurately than either test alone. The clinical benefit rate of KRAS WT/high EGFR GCN tumours was 82%.

Conclusion:

Our results show that automated EGFR SISH, in combination with KRAS mutation analysis, can be a useful and easily applicable technique in routine diagnostic practise for selecting patients for anti-EGFR therapy.     

EGFR and K-ras gene mutation status in squamous cell anal carcinoma: a role for concurrent radiation and EGFR inhibitors?

Background:

There is a growing appreciation for radio-sensitiser use in multi-modal cancer treatment models. Squamous cell anal carcinoma (SCAC) is a rare gastrointestinal tumour traditionally treated with concurrent chemotherapy and radiation. Cetuximab, an epidermal growth factor receptor (EGFR) inhibitor, has demonstrated significant efficacy when combined with radiation in squamous cell carcinoma of the head and neck (SccH&N). We wanted to assess EGFR and Kirsten-ras (K-ras) status in SCAC to see whether it compares with SccH&N.

Methods:

Over 90 SCAC paraffin-embedded biopsies were mounted onto a tissue microarray and were assessed for EGFR expression by immunohistochemistry. These samples were also assessed for the most frequently mutated K-ras and EGFR exons by high-resolution melting analysis.

Results:

The EGFR was present in over 90% of samples tested. The K-ras and EGFR mutations were absent in all samples tested, although a synonymous single-nucleotide polymorphism was found in 3 out of 89 samples tested for EGFR exon 19.

Conclusion:

The low rate of K-ras and EGFR mutations, coupled with the high surface expression of EGFR, suggests similarity in the EGFR signalling pathway between SCAC and SccH&N, and thus a potential role for EGFR inhibitors in SCAC. To our knowledge this is the largest cohort of invasive SCAC samples investigated for EGFR and K-ras mutations reported to date.     

Afatinib in Non‐Small Cell Lung Cancer Harboring Uncommon EGFR Mutations Pretreated With Reversible EGFR Inhibitors

Background.

Afatinib, an irreversible ErbB family blocker, is approved for treatment of patients with previously untreated non-small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutations. Efficacy of afatinib in EGFR tyrosine kinase inhibitor-naïve (TKI-naïve) patients with uncommon EGFR mutations (other than exon 19 deletions or exon 21 point mutations) has been reported; however, efficacy in TKI-pretreated patients with uncommon EGFR mutations is unknown.

Materials and Methods.

In the afatinib compassionate use program (CUP), patients with advanced or metastatic, histologically confirmed NSCLC progressing after at least one line of chemotherapy and one line of EGFR-TKI treatment were enrolled. Demographic data, mutation type, response rates, time to treatment failure (TTF), and safety in patients harboring uncommon EGFR mutations were reported.

Results.

In 60 patients (63% female, median age 63 years [range: 30–84 years]), a total of 66 uncommon EGFR mutations including 30 T790M mutations were reported (18.4% and 11%, respectively, of known EGFR mutations within the CUP). Most patients (67%) received afatinib as third- or fourth-line treatment. Median TTF was 3.8 months (range: 0.2 to >24.6 months; p = .244) in patients with uncommon mutations compared with 5.1 months (range: 0.1 to >21.1 months) in patients with common mutations (n = 165). Pronounced activity was observed with E709X mutations (TTF >12 months). No new safety signals were detected.

Conclusion.

Afatinib is clinically active and well tolerated in many TKI-pretreated NSCLC patients harboring uncommon EGFR mutations. Compared with results reported in TKI-naïve patients, activity was also indicated in patients with T790M and exon 20 insertion mutations.

Implications for Practice:

This analysis consists of a large database of non-small cell lung cancer patients with uncommon EGFR mutations who were previously treated with reversible EGFR tyrosine kinase inhibitors. Although indirectly assessed, the results indicate that patients with uncommon EGFR mutations can derive benefit from treatment with the irreversible ErbB family blocker afatinib, even in some cases of tumors harboring resistance-mediating exon 20 mutations. In this study, adverse events were modest and consistent with previous reports on afatinib.