Won et al. BMC Cancer 2010, 10:564 http://www.biomedcentral.com/1471-2407/10/564 Table 3 Immunohistochemical staining for tumors stratified by clinico-pathological variables Variable TP ERCC1 Cyclin D1 Survivin P53 Differentiation Well Others Vascular invasion Yes No Perineural invasion Yes No Lymphatic invasion Yes No LN metastasis Yes No T stage 1 2 3 4 No. 18 57 10 61 42 28 30 41 32 42 7 22 35 14 p 0.096 0.112 0.171 0.350 0.310 0.027 No. 11 28 3 32 23 11 17 18 19 19 2 14 15 8 p 0.557 0.383 0.087 0.181 0.126 0.083 No. 9 26 3 30 19 14 14 19 14 21 3 10 17 5 p 0.405 0.592 0.528 0.311 0.470 0.442 No. 14 39 4 46 30 19 16 34 24 29 10 12 26 6 p 0.344 0.495 0.258 0.170 0.091 0.806 No. 17 51 6 60 40 25 28 38 18 31 8 16 41 7 Page 5 of 8 p 0.190 0.459 0.222 0.226 0.274 0.009 TP, thymidine phosphorylase; ERCC1, excision repair cross complementing protein 1. TNM stage (Table 4). In a subgroup analysis stratified by type of cancer, these correlations were observed to be identical in GB cancer. Meanwhile, only two factors, differentiation and perineural invasion, were significantly correlated with survival time in BDC. In multivariate survival analysis, differentiation and TNM stage showed a significant impact on OS in GB cancer (HR = 0.472, 1.532; p = 0.039, 0.042). Meanwhile, in BDC, TNM stage was only significant prognostic factor affecting sur- vival (HR = 2.312; p = 0.001). The expression of p53, cyclin D1, survivin, TP, and ERCC1 did not indepen- dently predict poor outcome in univariate analysis. Among the 66 patients who received adjuvant treat- ment, there was no significant difference in TTR and OS associated with TP and ERCC1 expression (p = 0.212, 0.322 for TP; p = 0.591, 0.794 for ERCC1). Discussion Biliary tract cancer is a heterogeneous disease with diverse anatomical sites. In the present study, we inves- tigated the entire spectrum of biliary tract cancer to define anatomical site-related similarities and differ- ences. Several differences were observed between GB cancer and BDC. In clinico-pathological characteristics, Figure 2 Kaplan-Meier survival curves for time to recurrence (A) and overall survival (B) in biliary tract cancer according to anatomical sites.