Patients with tumours >4.0 cm showed significantly worse outcomes in RFS compared with those with smaller tumours. This relationship was also noted in patients with Stage I disease.

No abstract

The newly proposed classification for thymic malignancies does not serve as a prognostic prediction model for overall survival but served as a significant imbalance of stage distribution in our cohort. However, it appears to be beneficial, especially in clinical settings and recurrence-free survival analysis.

Malignant mesothelioma (MM) shows inactivation of the BRCA1-associated protein 1 (BAP1) gene. In this study, we found BAP1 mutations in 5 (26%) of the 19 cell lines that we established from Japanese MM patients, and examined functional differences between the WT and mutant BAP1. First, we studied the subcellular localization of BAP1, demonstrating that the WT primarily resides in the nucleus and that the mutant BAP1 is found in the cytoplasm of the cells. Transduction of the WT BAP1 vector into MM cells with homozygous deletion at the BAP1 3′ side resulted in both inhibition of cell proliferation and anchorage-independent cell growth, whereas BAP1 mutants of a missense or C-terminal truncated form showed impaired growth inhibitory effects. Next, we studied how BAP1 is involved in MM cell survival after irradiation (IR), which causes DNA damage. After IR, we found that both WT and mutant BAP1 were similarly phosphorylated and phospho-BAP1 localized mainly in the nucleus. Interestingly, BRCA1 proteins were decreased in the MM cells with BAP1 deletion, and transduction of the mutants as well as WT BAP1 increased BRCA1 proteins, suggesting that BAP1 may promote DNA repair partly through stabilizing BRCA1. Furthermore, using the MM cells with BAP1 deletion, we found that WT BAP1, and even a missense mutant, conferred a higher survival rate after IR compared to the control vector. Our results suggested that, whereas WT BAP1 suppresses MM cell proliferation and restores cell survival after IR damage, some mutant BAP1 may also moderately retain these functions.

Background. Programmed death ligand 1 (PD-L1) is reportedly expressed in various malignancies and is considered a prognostic factor. We attempted to reveal the usefulness of the PD-L1 expression as a prognostic factor in patients with thymoma.Methods. Eighty-one patients with thymoma who underwent surgical resection between 2004 and 2015 were retrospectively reviewed. The PD-L1 expression was evaluated by immunohistochemistry and stratified by the proportion of positive tumor cells. Strong membranous reactivity of the PD-L1 antibody in 1% or more of tumor cells was considered "positive." The association between the PD-L1 expression and the clinicopathologic features was investigated.Results. The PD-L1 expression was positive in 22 patients (27%) and negative in 59 patients (73%). The PD-L1 positivity was significantly associated with type B2 and B3 thymoma (p < 0.001) and stage III and IV disease (p [ 0.048). In addition, PD-L1 positive tumors showed a significantly higher maximum standardized uptake value than PD-L1 negative tumors (p [ 0.026). The 5-year disease-free survival rate was 82% in PD-L1 positive patients and 88% in PD-L1 negative patients, showing no significant difference (p [ 0.57). Furthermore, PD-L1 positivity was not an independent prognostic factor for the disease-free survival on a Cox proportional hazards analysis (p [ 0.59).Conclusions. A strong expression of PD-L1 in thymoma was significantly associated with type B2 and B3 and higher pathologic stages. In addition, PD-L1 positivity was associated with an increased maximum standardized uptake value of the tumor. However, patients with PD-L1 positive thymomas did not show a significantly worse prognosis than patients with PD-L1 negative tumors.