Gao et al. BMC Cancer 2011, 11:177 http://www.biomedcentral.com/1471-2407/11/177 Table 4 Association Between TUBB3 Expression 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 TUBB3 Staining Positive 8 9 5 36.4 86 (40.9-131.1) 201 (182.5-253.5) 0.049 0.046 0.029 Negative 8 2 1 72.7 237 (19.4-454.6) 388 (67.6-708.4) Discussion The treatment of gastric cancer is still a troublesome problem worldwide, and up to now there is not sys- tematic standard regimen for gastric cancer. Over 50% patients couldn’t respond to chemotherapy with the major obstacle is drug resistance. So how to improve the response and extend the life of patients is requested urgently. At present, the regimen of plati- num (cisplatin, oxaliplatin, etc.) combined with fluor- ouracil (5-FU, capecitabine, etc.) is most used for gastric cancer in China. Capecitabine is a new type flurouracil carbamates antitumor agent and widespread used by tumor patients due to its convenient adminis- tration, well tolerance, definite effect and low side effect. Animal experiments have shown that many Page 5 of 8 drugs, such as irinotecan, oxaliplatin, cisplatin and paclitaxel, had synergistic effect with capecitabine [32-34], and capecitabine plus paclitaxel or cisplatin regimens have been considered as desirable che- motherapy in clinical studies [13-15]. Based on our results, the response rate of capecitabine plus paclitaxel or cisplatin was 48.5% and 33.3%, respec- tively. However, although these regimens were effective in gastric cancer, over an half patients failed to respond due to drug resistance. So if we can find some predictive biomarkers for capecitabine plus paclitaxel to guide treatment of patients, there must be a very great improvement for response and survival. TP is a key enzyme in the metabolic pathway of capecitabine. TP enzyme, also called tumor related angiogenesis factor, is higher expressed in tumor tissues than in normal tis- sues, then the concentration of 5-FU in tumor tissues is raised followed by enhanced antitumor activity. In our results, the response rate, PFS and OS for TP positive patients are all higher than that in TP negative patients, which is similar with the results by other researchers [8-11]. According to above results, we analyzed TP expression in advanced gastric cancer and found the overall survival of TP positive patients was much better than that in TP negative patients. However, in different studies of colorectal cancer, data about the prognostic or predictive value of TP were conflicting: Meropol NJ et al [35] reported TP expression might be a predictive marker for capecitabine response, but Koopman et al [36] found TP expression didn’t show a predictive or prognostic value for capecitabine combination chemotherapy. Figure 2 PFS and OS curves for TUBB3 negative and positive patients receiving capecitabine plus paclitaxel.