[24]. Later on, the same research group found out that the mutation-detection yield of sequencing from RNA was coupled with the superior prediction of clinical efficacy to first-line TKIs [25]. The explanation selleck kinase inhibitor was that, contaminated nontumor cells within pleural fluid may have no or lower EGFR expression, using RNA instead of genomic DNA as the source for EGFR mutation

analysis could minimize the influence of nontumor cells. For blood samples, most reports used plasma rather than cell pellets for mutation analysis, because tumor cells in the blood are rare as compared with the cells of hematopoietic lineages. The documented sensitivity of plasma varied from 33% to 100%, which may be resulted from various detection methods or from different patients selleck products enrolled [17, 18, 23, 26, 27]. But using plasma encounter the same problem as using cell-free pleural fluid, namely,

it is impossible to precisely evaluate whether the tumor-derived DNA was adequately contained. The characterization learn more of circulating tumor cell might resolve the problem ultimately, since it is ascertain that the test was done on tumor cells. In the study by Maheswaran et al, there were 12 patients for whom specimens of the primary tumor, CTCs, and plasma were all available for EGFR mutation analysis. The genotyping of CTCs appeared to be more sensitive than plasma (92% Vs 33%, P= 0.009) [27]. The main problem now is that the technology of CTC enrichment still needs to be standardized and

generalized. In recent years, tremendous efforts have been made on CTC detection and characterization [28, 29]. In the near future, EGFR mutation analysis on CTC may become a reality in the routine clinical practice. Our study had two limitations, which hindered us from verifying the hypothesis mentioned above. First, although we and others have demonstrated that body fluid is feasible [13–18], analysis for EGFR mutations with DNA extracted from tumor tissue remains the gold standard. Nevertheless, since all the patients enrolled in this study couldn’t provide sufficient tumor tissue after routine pathological examination was done, the mutation status of the tumor tissue were not available and we CYTH4 could not testify whether there were still false negative results left after the extracted DNA were re-examined by ARMS. Second, although it is necessary to re-extract the nucleic acid with an optimized procedure by RNA or CTC, and then, to compare the mutation analysis with current study, the original body fluid samples of the patients were not preserved after the mutation analysis was done, the comparison could not be carried out. In order to address the two issues above, we had set a new research plan and the patients were now under enrolling.