Since IPASS reported, laboratories have gained experience of using existing EGFR mutation detection techniques on a spectrum of samples with varying tumor content and sample quality. Small biopsies and cytology samples
make up ∼30–80% of available diagnostic material, depending on diagnostic practices between different hospitals and countries , therefore their successful testing is paramount to ensure this sizeable Cisplatin purchase proportion of patients are given the opportunity to receive optimal treatment. The percentage of mutation testing that occurs using cytology samples can be very variable however, and is currently not consistent across institutions or countries . Smouse et al’s retrospective review of EGFR sequencing over a two year period at a US hospital noted that only 12/239 (5%) specimens tested for EGFR mutation were cytological in origin , with focus given to the testing
of high-quality tumor tissue samples. Conversely, Hagiwara et al. recently noted that ∼40% of samples submitted for EGFR mutation testing across three major commercial test centers in Japan were of cytological MS 275 origin , further commenting that this high percentage highlights that cytological samples are indispensable for testing all patients with advanced NSCLC. The aim of the current study was to investigate whether cytology/histology samples that were not included in the IPASS pre-planned exploratory biomarker analyses could be used successfully to define EGFR mutation status and predict which patients were more likely to respond to EGFR-TKI treatment. We describe data generated from pathology review and mutation analysis of the previously unanalyzed histology samples and previously unanalyzed cytology samples, with the aim of testing the outcome of patients with NSCLC as per the study protocol, but by looking at the full spectrum of samples that are available from this population
of patients. These data will help to inform the most appropriate thresholds for further trials, as well as the utility of samples received by diagnostic laboratories on a daily basis. Full details of IPASS (ClinicalTrials.gov identifier NCT00322452) have been published previously  and . Patients were eligible for Megestrol Acetate inclusion into the study if they had histologically or cytologically confirmed stage IIIB or IV pulmonary adenocarcinoma (including bronchoalveolar carcinoma), were never-smokers (<100 cigarettes in their lifetime) or former light smokers (stopped smoking ≥15 years previously and smoked ≤10 pack-years), and had received no prior chemotherapy, biologic therapy, or immunologic therapy. Patients provided written informed consent with separate consent for the optional assessment of EGFR biomarkers. The study protocol was approved by independent ethics committees at each institution.