Fluorescence in situ hybridization (FISH) is the primary method to detect ALK, ROS1 and RET fusions in NSCLC [14], [25] and [26]. However, it is not wildly used in China due to its high spent, time consuming and also VRT752271 research buy the interpretation of results. Immunohistochemistry (IHC) is another method to detect ALK fusion, but there is no standard procedure for all the labs and the same result could be explained differently by different pathologists. Soda showed us in his study

that different technologies should apply to different samples, and multiplex RT-PCR was applicable for the fluid samples [27]. Here, we use a reverse-transcript polymerase chain reaction (RT-PCR) method-ARMS-to detect ALK, ROS1 and RET fusions in 50 CB samples. Wu [12] used RT-PCR and FISH to detect ALK fusion and they found a concordance rate of 85%, but they did not check cell block samples that were ALK fusion positive using FISH. Soda [27] reported in their research that PCR-based detection of EML4-ALK should have a higher analytic sensitivity compared with

IHC or FISH. In this study, although we did not use FISH to conform the PCR results, we used DNA sequencing as a substitute. All the positive results using the PCR method were all conformed by DNA sequencing. We believe that the cell block samples could detect the three fusion genes using both RT-PCR and DNA sequencing. We tested the quality of cell block samples from the points of malignant cell ratio and PCR S3I-201 research buy controls, finding that they were qualified to do the gene detection. The fusion positive results were all validated by DNA sequencing and the specific variants were also given. The results indicate that cell block samples preserved at least 10 months

could be used to detect fusion genes. EML4-ALK fusion gene detection using plural effusions had been reported by Wu et al [12]. They used RT-PCR and direct sequencing methods and found a 34% presence in EGFR wild type lung adenocarcinoma patients. Shaw et al. [19] got a 33% prevalence in never/light smokers in EGFR wild type lung adenocarcinoma patients using FISH method. Although Cai et.al [28] used 19 cell block samples and 35 fine-needle aspirates to detect EGFR, KRAS and ALK genes in primary and metastatic Baricitinib lung adenocarcinomas, they did not show whether the CB samples be used for ALK detection or not. As far as we know, there is no study that reports the three fusion genes detected specially using CB samples. In the 50 EGFR wild type lung adenocarcinoma patients, EML4-ALK had a prevalence of 28%, which was a little lower than the former data [11] and [12]. Nonetheless, considering the small number of cases in our study, this slight difference should be reasonable. We had also examined ROS1 and RET fusion genes in the 50 samples.