Gao et al. BMC Cancer 2011, 11:177 http://www.biomedcentral.com/1471-2407/11/177 Page 6 of 8 Figure 3 PFS and OS curves for TUBB3 negative and positive patients receiving capecitabine plus cisplatin. Taxanes are a kind of antitumor drugs and mechan- isms about its resistance have been studied for a long time. Microtubule is the target of paclitaxel which induces microtubule stabilization, inhibits microtubule dynamics and interrupts cell divisions. Studies showed that TUBB3 high expressed in paclitaxel-resistant cells [37] and after transfecting TUBB3 cDNA into mamma- lian cells, cells with TUBB3 expression displayed resis- tant to paclitaxel [38]. Also in other studies about breast cancer, ovary cancer, head and neck neoplasms, there were relationship between TUBB3 expression and response or survival of paclitaxel. We studied the corre- lation in 33 samples treated with capecitabine plus pacli- taxel, and found that the response rate for TUBB3 negative patients was 72.7%, but only 36.4% in TUBB3 positive patients. Moreover, in cohort 1, the prognosis of TUBB3 negative patients was much better than that of TUBB3 positive patients. Our results indicated there was not relationship between TUBB3 expression and response or survival in patients receiving capecitabine plus cisplatin, so TUBB3 expression could act as a pre- dictor of paclitaxel efficacy. TP could be upregulated after the treatment of taxane in preclinical trial [39], we analyzed the relationship between TP, TUBB3 expressions and the response or survival of patients. Interestingly, the response rate in TP positive & TUBB3 negative patients was 87.5%, but only 14.3% in TP negative & TUBB3 positive patients. This result will need to be further confirmed in future studies. Recently, many studies put the sights into genomic polymorphisms in genes involved in drug metabolic pathway and correlated with the target of agents. Few genes have been used to guide clinical medication, such as K-RAS [40], C-KIT [41], EGFR [42], Her-2 [43], and so on, but for most drugs there were no predictive mar- kers. According to our results, TP and TUBB3 may be Table 5 Association Between TP, TUBB3 Expressions and Response or Survival CR+PR No. SD No. PD No. Response rate (%) P Median PFS (days) (95% CI) P Median OS (days) (95% CI) P TP positive & TUBB3 negative 7 1 0 87.5 251 (146.4-354.6) 393 (340.9-530.8) TP, TUBB3 Staining 0.01 0.003 0.439 TP negative & TUBB3 positive 1 3 3 14.3 84 (52.5-110.7) 196 (70.3-461.7)