This study highlights the feasibility of systematic NSCLC testing by both FISH and IHC in routine practice. Many preanalytical factors may account for the apparent discrepancies between both methods, suggesting that hierarchical screening may underscore ALK-positive cases. This significant level of discrepancy supports the need of combined testing to optimize the detection of ALK-inhibitor-eligible patients given that some patients with discordant testing were found to respond to crizotinib.

The development of targeted therapies creates a need to discriminate tumours accurately by their histological and genetic characteristics. Here, we aim to identify gene expression profiles and single markers that recapitulate the pathological and genetic background of non-small cell lung cancer (NSCLC). We performed cDNA microarray analysis on a series of 69 NSCLCs, with known mutation status for important genes, and six normal lung tissues. Unsupervised cluster analysis segregated normal lungs from lung tumours and lung tumours according to their histopathology and the presence of EGFR mutations. Several transcripts were highly overexpressed (by approximately 20 times) in squamous cell carcinomas (SCCs) relative to adenocarcinomas (ACs) and confirmed by immunohistochemistry in an independent cohort of 75 lung tumours. Expression of 13 genes constituted the most prominent hallmarks of EGFR-mutant tumours, including increased levels of proline dehydrogenase (PRODH) and down-regulation of X-box binding protein 1 (XBP1). No genes were differentially expressed, with a fold change >or= 4 or

TLX1 is a homeodomain transcription factor generally associated with a favorable outcome in T-cell acute lymphoblastic leukemia (T-ALL). However, the molecular mechanisms of TLX1 deregulation remain unclear and various transcript levels in the absence of 10q24 abnormalities have been reported. A reproducible and accurate delineation of TLX1 ؉ T-ALL will be necessary for proper therapeutic stratification. We have studied 264 unselected T-ALLs (171 adults and 93 children) and show that T-ALLs expressing high levels of TLX1 (n ‫؍‬ 35, 13%), defined as a realtime quantitative polymerase chain reaction (RQ-PCR) level of TLX1 greater than 1.00 ABL, form a homogeneous oncogenic group, based on their uniform stage of maturation arrest and oncogenetic and transcriptional profiles. Furthermore, TLX1-high T-ALLs harbor molecular TLX1 locus abnormalities in the majority (31/ 33), a proportion largely underestimated by standard karyotypic screening. TALLs expressing TLX1 at lower levels (n ‫؍‬ 57, 22%) do not share these characteristics. Prognostic analysis within the adult LALA94 and GRAALL03 prospective protocols demonstrate a better eventfree survival (P ‫؍‬ .035) and a marked trend for longer overall survival (P ‫؍‬ .059) for TLX1-high T-ALLs, while the expression of lower levels of TLX1 does not impact on prognosis. We propose that TLX1 ؉ T-ALLs be defined as cases expressing TLX1/ABL ratios greater than 1 and/or demonstrating TLX1 rearrangement. Therapeutic modification should be considered for those patients. (Blood. 2007; 110: [2324][2325][2326][2327][2328][2329][2330]