Gao et al. BMC Cancer 2011, 11:177 http://www.biomedcentral.com/1471-2407/11/177 responders (43.1%), 18 patients with stable disease (35.3%), and 11 patients with progressive disease (21.6%). The median PFS and OS of 51 patients were 120 days and 265 days, respectively. There were no sig- nificant differences of response and survival between cohort 1 and cohort 2 (Table 2). The response rate, median PFS and OS in cohort 1 and cohort 2 were 48.5%, 120 days, 252 days and 33.3%, 116 days, 265 days, respectively. TP IHC and Response, Survival Negative and positive staining for TP protein in 51 tumor samples were 26 and 25 samples (Figure 1, left lane). Of the 25 patients with positive TP, there were 14 responses (56%), compared with 8 of 26 responses (30.8%) seen in negative TP tumors (P = 0.069, Table 3). Also, the median PFS and OS in TP positive samples were longer than that in TP negative samples, but sig- nificant difference only existed in OS (P = 0.017) not in PFS (P = 0.613) between two groups (Table 3). TUBB3 IHC and Response, survival IHC of TUBB3 was done in cohort 1 and cohort 2, negative and positive staining for TUBB3 in cohort 1 (33 samples) were 11 and 22 samples (Figure 1, right lane). Among cohort 1, of the 22 patients with positive TUBB3, there were 8 responses (36.4%), compared with 8 of 11 responses (72.7%) seen in negative TUBB3 tumors (P = 0.049); also, the median PFS (P = 0.046) and OS (P = 0.029) in TUBB3 positive samples were much shorter than those in TUBB3 negative samples (Table 4 and Figure 2). Among cohort 2, the response rates in TUBB3 negative patients (n = 7) and positive patients (n = 11) were 28.6% and 36.4%, respectively (P = 0.73). Also, there weren’t correlations between TUBB3 expressions and median PFS (P = 0.562) or OS (P = 0.633) in cohort 2 (Figure 3). Table 2 Response and Survival for all patients Outcome CR+PR No. SD No. PD No. Response rate Median PFS (days) 95% CI Median OS (days) 95% CI Cohort 1 (n = Cohort 2 (n = 33) 18) P No. 16 11 6 16 % 48.5 33.3 18.2 48.5 No. 6 7 5 6 % 33.3 22 38.9 18 27.8 11 33.3 0.668 22 Total (n = 51) No. % 43.1 35.3 21.6 43.1 120 77.2-162. 8 252 157. 5-346.5 116 0-267.1 265 107.0-423.0 120 0.377 79.7-160.3 265 0.354 181.0-349.0 NOTE: PFS, progression-free survival; OS, overall survival; 95% CI: 95% confidence interval Page 4 of 8 Figure 1 IHC presenting TP and TUBB3 expressions (magnification, ×400). A, TP negative; B, TP positive; C, TUBB3 negative; D, TUBB3 positive. TP, TUBB3 IHC and Response, survival Among cohort 1, TP positive & TUBB3 negative stain- ing was 8 samples, with 7 responses (87.5%), but for TP negative & TUBB3 positive staining samples, only 1 of 7 responses (14.3%) (P = 0.01, Table 5). The median PFS (251d) and OS (393d) in TP positive & TUBB3 negative staining samples were longer than those (PFS: 84d, OS: 196d) in TP negative & TUBB3 positive staining sam- ples, although there was no statistical difference of OS between two groups (P = 0.003 for PFS, P = 0.439 for OS, Table 5 and Figure 4). There were 15 samples (8 responses, 53.3%) displaying TP positive & TUBB3 posi- tive staining with median PFS 122d and median OS 207d, and 3 samples (all with SD) displaying TP nega- tive & TUBB3 negative staining. Table 3 Association Between TP 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 TP Staining (n = 51) Positive 14 5 6 56 156 (71.5-240.5) 365 (123.0-567.0) 0.069 0.613 0.017 Negative 8 13 5 30.8 107 (66.7-147.3) 214 (74.8-317.2)