Paraneoplastic autoimmune diseases associate occasionally with small cell lung cancers and gynecologic tumors. However, myasthenia gravis (MG) occurs in at least 30% of all patients with thymomas (usually present at MG diagnosis). These epithelial neoplasms almost always have numerous admixed maturing polyclonal T cells (thymocytes). This thymopoiesis—and export of mature CD4⁺T cells—particularly associates with MG, though there are rare/puzzling exceptions in apparently pure epithelial WHO type A thymomas. Other features potentially leading to inefficient self-tolerance induction include defective epithelial expression of the autoimmune regulator (AIRE) gene and/or of major histocompatibility complex class II molecules in thymomas, absence of myoid cells, failure to generate FOXP3⁺ regulatory T cells, and genetic polymorphisms affecting T-cell signaling. However, the strong focus on MG/neuromuscular targets remains unexplained and suggests some biased autoantigen expression, T-cell selection, or autoimmunization within thymomas. There must be further clues in the intriguing serological and cellular parallels in some patients with late-onset MG but without thymomas—and in others with AIRE mutations—and in the contrasts with early-onset MG, as discussed here.

Background: Cyclin D1 gene regulates cell cycle and plays an important role in the tumorigenesis of human cancers. The association between cyclin D1, clinicopathologic parameters and prognosis in oral cavity squamous cell carcinoma (OSCC) is inconclusive. Methods: A total of 264 male OSCCs were examined for cyclin D1 protein expression using immunohistochemistry (IHC). The expression levels of cyclin D1 were defined as overexpression when more than 10% of tumor cells displayed nuclear staining with moderate to strong intensity. Results: Overexpression of cyclin D1 was found in 97 (36.7%) OSCCs. Cyclin D1 protein overexpression was significantly associated with lymph node metastasis (P = 0.002), tumor cell differentiation (P = 0.031) and tumor stage (P = 0.051), but not associated with age onset, cigarette smoking, alcohol drinking, or areca quid chewing. Overexpression of cyclin D1 was also significantly associated with poor clinical outcomes in terms of disease-free survival (DFS, P = 0.002) and overall survival (OS, P < 0.001). The effects of cyclin D1 protein overexpression on DFS (hazard ratio (HR) = 1.540; 95% confidence interval (CI), 1.068 - 2.222) and OS (HR = 1.702; 95% CI, 1.168 - 2.480) were still existed after adjusting for clinicopathological paremeters (such as age, primary tumor status, tumor cell differentiation, and lymph node metastasis) using logistic multivariate analysis. Conclusion: Cyclin D1 protein worked as an independent prognostic factor and can be as a biomarker for the aggressiveness of OSCC.