ALK rearrangement in a large series of consecutive non-small cell lung cancers: Comparison between a new immunohistochemical approach and fluorescence in situ hybridization for the screening of patients eligible for crizotinib treatment

Context. - Echinoderm microtubule associated protein-like 4-anaplastic lymphoma receptor tyrosine kinase (EML4-ALK) translocation has been described in a subset of patients with non-small cell lung cancer (NSCLC) and has been shown to have oncogenic activity. Fluorescence in situ hybridization (FISH) is used to detect ALK-positive NSCLC, but it is expensive, time-consuming, and difficult for routine application. Objective. - To evaluate the potential role of immunohistochemistry (IHC) as a screening tool to identify candidate cases for FISH analysis and for ALK inhibitor therapy in NSCLC. Design. - We performed FISH and IHC for ALK and mutational analysis for epidermal growth factor receptor (EGFR) and KRAS in 523 NSCLC specimens. We conducted IHC analysis with the monoclonal antibody D5F3 (Ventana Medical Systems, Tucson, Arizona) and a highly sensitive detection system. We also performed a MassARRAY-based analysis (Sequenom, San Diego, California) in a small subset of 11 samples to detect EML4-ALK rearrangement. Results. - Of the 523 NSCLC specimens, 20 (3.8%) were positive for ALK rearrangement by FISH analysis. EGFR and KRAS mutations were identified in 70 (13.4%) and 124 (23.7%) of the 523 tumor samples, respectively. ALK rearrangement and EGFR and KRAS mutations were mutually exclusive. Of 523 tumor samples analyzed, 18 (3.4%) were ALK+ by IHC, 18 samples (3.4%) had concordant IHC and FISH results, and 2 ALK+ cases (0.3%) by FISH failed to show ALK protein expression. In the 2 discrepant cases, we did not detect any mass peaks for the EML4-ALK variants by MassARRAY. Conclusions. - Our results show that IHC may be a useful technique for selecting NSCLC cases to undergo ALK FISH analysis

Epidermal growth factor receptor and K-RAS mutations in 411 lung adenocarcinoma: A population-based prospective study

Targeting the epidermal growth factor receptor has played a central role in advanced non-small cell lung cancer research, treatment, and patient outcomes over the last several years; however, a number of questions about this approach remain to be addressed. Through the Istituto Toscano Tumori and the Italian Association of Women Against Lung Cancer Project, we collected 411 lung adenocarcinomas from several clinical centers in Tuscany. Mutations were assessed by sequencing exons 18-21 of the epidermal growth factor receptor gene, and by restriction fragment length polymorphism analysis of codons 12 and 13 of the K-RAS gene. Epidermal growth factor receptor mutations (12.6%) were more frequently observed in females (p<0.0001), in non-smokers (p=0.005), and in the presence of bronchioloalveolar features (p=0.0004). K-RAS mutations (17.9%) were more frequent in males (p=0.0007) and were associated with smoking habits (p=0.005). Epidermal growth factor receptor and K-RAS mutations were mutually exclusive (p=0.001). We focused on 21 female patients with advanced/metastatic lung adenocarcinoma who received gefitinib 250 mg/day (expanded access) or erlotinib 150 mg/die as second/ third-line therapy; partial response was associated with classic epidermal growth factor receptor mutations (p=0.006) and with a non-smoking history (p=0.02). None of the female patients with partial response and/or stable disease showed K-RAS alterations. Although the data obtained in our study have yet to be analyzed and confirmed with a larger number of patients treated with tyrosine kinase inhibitors, they should provide useful information for targeted therapy, in particular for non-smoking female lung cancer patients