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.

Epidermal Growth Factor (EGFR) copy number aberrations in esophageal and gastro-esophageal junctional carcinoma.

BACKGROUND: Clinical trials of agents targeting epidermal growth factor receptor (EGFR) in esophageal carcinoma (EC) have indicated a minority subgroup responsive to anti-EGFR therapies. Other investigations suggest increases in EGFR copy number are associated with poor prognosis in EC, but have used a variety of different techniques and tested numbers remain small. A validated assay for EGFR copy number in EC is needed, to allow investigation of EGFR copy number gain as a predictive biomarker for the anti-EGFR responsive subgroup of patients. We developed a scoring system in EC based upon established systems for EGFR fluorescence in-situ hybridisation (FISH) in lung cancer, and applied this in a series of 160 UK patients with advanced EC. RESULTS: Dual colour FISH on formalin fixed paraffin embedded (FFPE) biopsies were scored independently by two operators as: disomy (score = 1), low trisomy (score = 2), high trisomy (score = 3), low polysomy (score = 4), high polysomy (score = 5) and amplification (score = 6). EGFR FISH positive cases (scores 5 and 6) were found in 32/160 (20 %) tumours, with high polysomy in 22 (13.8 %) and amplification in 10 (6.3 %). Two independent operator scores for FISH positivity were 100 % concordant. EGFR FISH positive status was not associated with clinic-pathological features. EGFR amplification was associated with worse survival (HR = 2.64, 95 % CI 1.04 to 6.71, p = 0.03). CONCLUSION: Our FISH scoring system for EGFR in advanced EC identifies a significant subgroup (20.0 %) of FISH positive patients. EGFR amplification, which is found in 6.3 %, is associated with poor survival. It is not known if there is a role for EGFR targeted treatment in this subgroup of patients, however we are now utilising this EGFR FISH assay and scoring system in biopsies from clinical trials utilising anti-EGFR targeted therapies.

A case-control study of Parkinson's disease and tobacco use: gene-tobacco interactions.

A case-control study of genetic, environmental, and occupational risk factors for Parkinson's disease (PD) was carried out in five European countries (Italy, Malta, Romania, Scotland, and Sweden) to explore the possible contribution of interactions among host and environmental factors in sporadic PD. Whereas smoking habits confirmed its negative association with PD, a possible modulatory role of genetic polymorphisms was investigated to obtain further mechanistic insights. We recruited 767 cases of PD and 1989 age-matched and gender-matched controls. Participants completed an interviewer-administered questionnaire including the history of smoking habits. The polymorphisms of genes involved either in metabolism of compounds contained in tobacco smoke (CYP2D6, CYP1B1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, SOD2, EPHX and NAT2) or in dopaminergic neurotransmission (MAOA, MAOB, DAT1 and DRD2) were characterized by PCR based methods on genomic DNA. We found evidence of statistically significant gene-tobacco interaction for GSTM1, NAT2, and GSTP1, the negative association between tobacco smoking and PD being significantly enhanced in subjects expressing GSTM1-1 activity, in NAT2 fast acetylators, and in those with the GSTP1*B*C haplotype. Owing to the retrospective design of the study, these results require confirmation.

A rapid method of screening for N-acetyltransferase (NAT2) phenotype by use of the WAVE DNA fragment analysis system.

N-Acetyltransferase 2 (NAT2) is involved in Phase II biotransformation of a variety of toxicants. Polymorphisms in the NAT2 gene result in a slow acetylator phenotype, which has been associated with various cancers and neurodegenerative diseases. To date most studies investigating NAT2 genotype/phenotype have adopted an RFLP approach, which is both expensive and time-consuming. Using the Wave DNA fragment analysis system, we have developed a fast and robust method of identifying two polymorphisms (C282T and T341C) of the NAT2 gene which allows identification of the most common slow acetylator alleles found in Caucasian populations: NAT2*5, NAT2*6, NAT2*7, and NAT2*14. This was done by comparing phenotype status in 126 samples genotyped by RFLP analysis and also by Wave analysis for the polymorphisms C282Tand T341C. All 126 samples analyzed by both RFLP and Wave analysis gave consistent phenotype results and 100% correlation was achieved between the two methods.