A rational diagnostic algorithm for the identification of ALK rearrangement in lung cancer: a comprehensive study of surgically treated Japanese patients.

BACKGROUND: EML4-ALK fusion gene is found in only a small subset (2-6%) of non-small cell lung cancer. There is an urgent need to establish a rational diagnostic algorithm to identify this rare but important fusion in lung cancer. METHODS: We performed a comprehensive analysis of EGFR/KRAS mutation and ALK rearrangement in a total of 360 surgically resected lung cancers. ALK rearrangement was examined by 3 analyses: multiplex reverse transcription-PCR, fluorescent in situ hybridization (FISH), and immunohistochemistry (IHC) with the intercalated antibody-enhanced polymer method. A scoring system was used for IHC (iScore). A test set (202 patients with unselected lung cancer) was used for proposing a diagnostic algorithm. This diagnostic algorithm was validated in 158 patients with EGFR and KRAS mutation-negative adenocarcinoma. RESULTS: ALK rearrangement was identified in 2 patients (1.0%) from the test set and both adenocarcinomas were negative for EGFR and KRAS mutations. The results of FISH and RT-PCR were completely matched. The highest iScore 3 was found only in the 2 positive cases. A diagnostic algorithm was proposed: IHC screening for ALK rearrangement followed by confirmatory FISH. In the validation set, 8 cases (5.1%) had iScore 3 and were positive for FISH, while the other cases had iScore 0 and were negative for FISH. CONCLUSIONS: Screening for ALK rearrangement by IHC followed by confirmatory FISH is a rational diagnostic algorithm. If needed, patients may be selected for screening ALK rearrangement by their EGFR and KRAS mutation status

Exercise oxygen desaturation is a predictor of cardiopulmonary complications after lung resection

Background To investigate whether oxygen desaturation during low technology tests was associated with complications after lung resection.Methods A retrospective cohort study was conducted on 1097 candidates for pulmonary resection; seven metabolic equivalents in the Master’s double two-step test were loaded. The predicted postoperative (PPO) forced expiratory volume in 1 s and PPO diffusing capacity of the lung for carbon monoxide were estimated. The patients were divided into three groups: those with both values ≥60% (≥60% group (n=298)), either value <30% (<30% group (n=112)) and others (30%–60% group (n=687)). The relationships between postoperative cardiopulmonary complications and exercise stress test based on availability, symptoms and percutaneous oxygen saturation values were investigated in each group.Results Τhe cardiopulmonary morbidity rates in the ≥60%, 30%–60%, and <30% groups were 7.7%, 14.6%, and 47.3%, respectively. Multivariate analyses revealed that predictors of complications were age (OR 0.96; p<0.001), male sex (OR 1.74; p=0.016) and exercise oxygen desaturation (EOD) >4% (OR 2.39; p=0.001) in the 30%–60% group, and male sex (OR 3.76; p=0.042) and EOD >4% (OR 2.28; p=0.030) in the <30% group.The two-flight test (TFT) was performed in 181 patients (22.8%); desaturation >4% in the TFT was also a predictor of complications.Conclusions A low technology test is also valuable for high-risk patients. EOD >4% is a predictor of postoperative complications.Clinical registration This study is a non-interventional observational study and has not been registered in a public database. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology reporting guidelines.This study was approved by the Ethics Committee of the Juntendo University School of Medicine (no. 2016085)

Clinicopathological characteristics of adenocarcinoma according to <i>ALK</i> rearrangement status.

a<p>Fisher’s exact test.</p>b<p><i>P</i> values were derived from a comparison between never smokers and smokers.</p><p>CEA, carcinoembryonic antigen.</p

Correlation of the results between <i>ALK</i> IHC and FISH in all patients.

<p>IHC, immunohistochemistry; FISH, fluorescent <i>in situ</i> hybridization.</p

Fluorescent in situ hybridization (FISH) assay for <i>ALK</i> using dual-color break-apart probe.

<p>Distinct red (thick arrow) and green (thin arrow) break apart signals indicate the <i>ALK</i> rearrangement, and a fusion signal (arrow head) represents wild-type <i>ALK</i> gene.</p

Histological features of <i>ALK</i>-positive and <i>ALK</i>-negative adenocarcinomas on H&E stain (A, B, C, D) and on ALK immunostaining by the iAEP method (E, F, G, H).

<p>P3 and P7 (A and B, respectively), adenocarcinomas with mucinous cribriform pattern, showed iScore 3 (E and F, respectively); N1 (C), squamous cell carcinoma showed iScore 1 (G); N3 (D), small cell carcinoma showed iScore 2 (H).</p