The first one was that the overall mutation rate was pretty lower than the average rate of Asian ethnic detected by sequencing (30-40%) [11], the second one was selleck screening library that quite a few patients response well with the TKIs therapy although their results of the mutation test are negative. We inferred that the low sensitivity of

sequencing may result in the two problems. In order to verify this speculation, we selected 50 patients with TKIs therapy experience from the patients who joined the EGFR mutation analysis using body fluids, re-evaluated the EGFR mutation status of the extracted DNA by ARMS, a method with sensitivity of 1%, and analyzed the clinical outcome of TKIs retrospectively. We found that ARMS could improve the mutation detection rate and the mutation positive patients responded well with TKIs therapy, but the correlation between mutation negative patients and TKIs therapy was still unsatisfactory. The results indicate that sensitivity of the method was not all the answers for the problems. We hypothesized that, as an alternative solution, the extraction procedure of nucleic acid should also be taken into consideration.

The results of this study were reported in the present manuscript. Materials and methods Sample collection and processing EGFR sequencing for exon 19 and 21 is one of the

routine tests for NSCLC patients who want to AZD1152-HQPA purchase initiate TKIs therapy in our hospital. The informed consent was obtained from each patient prior to the test. Pleural fluid samples were used as alternative clinical specimen for patients who couldn’t provide sufficient tumor tissue. For patients who couldn’t provide tumor tissue and pleural fluid, plasmas were used as an alternate. DNA was extracted from 400 μL supernatant of the pleural fluid or plasma by QIAamp DNA Blood Mini kit (Qiagen, Hilden, Germany) and eluted with 50 μL H2O. The extracted DNA was stored at -20°C until used. EGFR exon Calpain 19 and 21 were amplified by polymerase chain reaction (PCR) using nested primer (Table 1) with Ex Taq polymerase (Takara, Tokyo, Japan). The first cycle of amplifications were performed using a 5 min initial denaturation at 95°C; followed by 30 cycles of 45 s at 95°C, 45 s at 54°C, and 1 min at 72°C; and a 6 min final extension at 72°C. Production of the first cycle was amplified in the secondary cycle using same condition as first one. The final products were cleared and sequenced with the internal primers using ABI PRISM 3730 DNA Analyser (Applied Biosystems, Foster City, CA, USA).