Search

e20632 Background: The use in routine clinical practice of the EGFR tyrosine kinase inhibitors is limited to patients with advanced or metastatic non-squamous non-small cell lung cancer (NSCLC) who have known EGFR mutations. Currently, patient care has to respond to several imperatives to make it broadly available to all patients; fast and accurate detection of EGFR mutations by a sensitive and specific standardized cost-effective method, easy-to-implement in settings with limited expertise in molecular diagnostics. The possibility to obtain EGFR testing results in less than few hours in a large number of pathology laboratories is recently guaranteed by the Idylla system. Methods: We evaluated the Idylla system (Biocartis) for the detection of EGFR mutations in archived formalin-fixed paraffin-embedded (FFPE) tumor samples from a series of 18 patients with lung adenocarcinoma and compared these results with those obtained by the Therascreen EGFR Pyro assay (Qiagen)-ISO 15189 accredited laboratory method. The results obtained with the two methods were compared on both whole tumor sections from surgical specimens and on tissue sections from three artificially constructed small biopsies (~1 mm diameter) from the same FFPE blocks. Cost-effectiveness and turnaround time comparison between the two methods was performed. Results: In the first assessment on whole tissue sections, the Idylla and pyrosequencing results had an agreement of 94%. When assessed on biopsy cores, Idylla demonstrated agreement with pyrosequencing in 16 of 18 cases (89%). The Idylla EGFR mutation assay produced results faster (sample to result time was about 180 minutes with about 2 minutes of hands on time) than pyrosequencing (sample to result time about 12 hours). For each patient, the Idylla was more cost-effective than pyrosequencin. Conclusions: The Idylla system showed a good sensitivity and was cost-saving in our setting. Because of the easy workflow, the Idylla system has the potential to expand EGFR testing to more pathology laboratories in a reliable and fast manner.

e20500 Background: Elderly patients have an eroded immune characterized by a progressive decline in immune surveillance that favors infection and cancer development. Tumor cells can escape immune surveillance by upregulating inhibitory immune checkpoint such as PD-L1. High expression of PD-L1 was reported in association with CD8+T-cell exhaustion and increased levels of CD33+ myeloid-derived suppressor cells. Although low CD4/CD8 ratio is associated with increased mortality, the status of the CD4+T-cells as a clinical marker of immunosenescence is less well characterized in the field of aging. The aim of this study was to determine the presence of immunosenescence biomarkers according to age in non-small cell lung cancer (NSCLC) patients and to evaluate them as predictive biomarkers of patients’ outcome. Methods: One hundred NSCLC patients, matched by age (50 patients < 70 years, 50 patients ≥70 years) were included. An automated 4-Plex optical IHC assay was developed on the Discovery ULTRA automated stainer using monoclonal antibodies PD-L1 (SP263), CD4, CD8, and CD33. The stained slides were scanned with Nanozoomer HT 2.0 Scanner, and analyzed with Calopix software. Results: The CD4/CD8 ratio and PD-L1 expression in tumor and immune cells were significantly lower in elderly NSCLC patients ≥70 years than in age-paired patients, while absolute count of CD33+ was increased. Patients with CD4/CD8 ratio higher than two, high PD-L1 density and low CD33+ frequency achieved increase in median disease-free survival. Conclusions: Distribution of PD-L1, CD4, CD8, and CD33 cells was influenced by age in NSCLC patients. The proportion of CD8 + CD28- T cells, CD4+ T cells and CD4/CD8 ratio may be used as predictive biomarkers of anti-PD-L1 therapy efficacy in NSCLC patients. The automated 4-Plex IHC assay together with its respective digital analysis could serve as a tool for further characterizing tumors and their microenvironment and provide a better understanding of which patients may benefit from immunotherapy.

7591 Background: The implementation of new theranostic biomarkers in Oncology is leading to impressive therapeutic improvements. In patients with lung cancer, the possibility to use Circulating Tumor Cells (CTCs) as a non-invasive theranostic approach is a clinically appealing challenge. Adenocarcinomas with EML4-ALK rearrangement are a new molecular subgroup of lung tumors with very good response to Crizotinib, an ALK inhibitor. We have thus aimed at developing an informative assay characterizing the ALK-gene status in CTCs isolated from patients with lung cancer. Methods: CTCs were isolated preoperatively using Isolation by Size of Epithelial Tumor cells method (ISET) from 65 patients with lung adenocarcinoma and blindly screened for ALK-gene status. ALK break-apart fluorescence in situ hybridization (FISH) (LSI ALK dual colour probes set) and immunochemistry using an anti-ALK antibody (5A4 clone) were blindly performed on CTCs and corresponding tumor tissues and results were compared. Results: Two patients consistently showed ALK-gene rearrangement and strong ALK protein expression in CTCs and corresponding tumor samples. Negative results (both ALK FISH and ALK immunochemistry) were found in CTCs and corresponding tumor samples from the other 63 patients. Conclusion: We have developed an approach allowing to characterize ALK-gene status in CTCs from patients with lung cancer and shown consistent results in CTC and tumor tissues. These preliminary results encourage larger studies and open new avenues for non-invasive, real-time, theranostic monitoring of cancer patients.