Tumor budding and dedifferentiation in gallbladder carcinoma: potential for the prognostic factors in T2 lesions.

Dedifferentiation (DD) is often encountered in gallbladder carcinoma (GBC) and poor prognosis with budding (BD) has been reported for other malignancies. However, the features of DD and BD in GBC remain unclear. The purpose of this study was to clarify the features and prognostic potential of DD and BD in GBC. A total of 80 patients with GBC (excluding intramucosal cancer) were enrolled. DD was histopathologically evaluated as tumors in which the grade of the invasive front is higher than the grade at the surface. BD was defined as an isolated single cancer cell or a cluster of fewer than five cancer cells at the invasive front. Of the 80 patients, 47 (58.8%) were positive for BD and 33 (41.2%) were positive for DD. Both BD and DD correlated significantly with disease-specific survival in univariate analysis (P < 0.0001 and P = 0.0013, respectively), but they were not identified as independent prognostic factors by multivariate analysis. In univariate analysis according to T stage, both BD and DD correlated significantly with survival in patients with T2 (n = 32) tumor (P = 0.0011 and P = 0.0018, respectively), whereas no prognostic impact in patients with T1b (n = 8), T3 (n = 34), or T4 (n = 6) tumor. Both DD and BD are frequently observed in GBC and reflect prognosis, particularly for T2 lesions. Therefore, the status of BD and DD should be taken into consideration in pathological reports on GBC.