Immunohistochemical expression of TFF1 is a marker of poor prognosis in retinoblastoma.

The risk of relapse in retinoblastoma is currently determined by the presence of high-risk histopathologic factors in the enucleated eye. However, the probability of developing metastatic disease is heterogeneous among these patients. Evaluating a biological marker to identify high-risk patients could be useful in clinical setting. This study aims to evaluate whether the expression of TFF1, a surrogate for subtype 2 retinoblastoma, is a prognostic marker for relapse and death. This multicenter cohort study included 273 patients, 48 of whom had extraocular disease. Immunohistochemical staining were performed for CRX, ARR3, TFF1, and Ki67. Tumors were classified as histological subtype 1 (HS1) if they had low or no expression of TFF1 (quick score (QS) ≤ 50) and as histological subtype 2 (HS2) if they expressed TFF1 diffusely (QS > 50). We studied the association between HS classification and outcome. Of 273 patients, 35.9% were classified as HS1, 59.3% as HS2 and 4.8% were not evaluable. In multivariate analysis, patients with HS2 tumors had a higher probability of relapse and death than those with HS1 (p < .0001 and p = .00020, respectively). We identified a higher-risk subgroup among HS2 tumors, presenting non-mutually exclusive expression of ARR3 and TFF1 and had an increased risk of relapse and death compared with tumors that displayed mutually exclusive expression (p = .012 and p = .027, respectively). Expression of TFF1, especially when it is not-mutually exclusive with ARR3, is an independent significant marker of poor outcome in retinoblastoma.