ABSTRACT
Background: Enhancer of zeste homolog 2 (EZH2) is one of the major epigenetic modifiers involved in the transcriptional repression of target genes through trimethylation of H3K27 (lysine 27 residue of histone H3). Deregulated expression of both EZH2 and H3K27me3 has been implicated in the biological behavior and prognostic outcome of various malignancies. Aim: To assess the role of EZH2 and H3K27me3 in the carcinogenesis of urothelial carcinoma of urinary bladder. Materials and Methods: One hundred fifty consecutive urothelial carcinoma cases of urinary bladder (54.7% high-grade) were included in this study. Immunohistochemical analysis for EZH2 and H3K27me3 was performed on whole tissue sections. A multiplication score obtained by multiplying staining intensity and proportion of positively stained neoplastic cells was used for assessment. Results: EZH2 showed a significant correlation with the tumor grade and lamina propria invasion (p < 0.001). The cases with high EZH2 expression showed a significantly high proliferative index (Mean- 32.7%; p < 0.001). In contrast, negative and low expression of H3K27me3 was significantly more common in high-grade cases (p = 0.006). The expression of H3K27me3 was significantly associated with lamina propria (p = 0.01) and deep muscle invasion (p = 0.007). EZH2 showed a significantly higher expression in the high-grade invasive areas as compared to the high-grade non-invasive areas of the same tumor (p = 0.03). Conclusions: This study establishes an important role of the key epigenetic regulators EZH2 and H3K27me3 in the pathobiology of urothelial carcinomas. Strong expression of EZH2 and weak expression of H3K27me3 are associated with higher grade, proliferative index and invasive behavior.
ABSTRACT
Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy. Extensive rhabdoid morphology in ACC has been described recently in very few cases. The proportion of rhabdoid morphology and the role of SMARCB1/ INI1 expression in these tumor cells to diagnose the specific variant is not described in the literature. We reviewed the clinicopathological features of nine cases of adrenocortical neoplasm. Out of which, three cases of ACC showed predominant rhabdoid morphology. Large discohesive cells with abundant cytoplasm containing eosinophilic inclusions, eccentric vesicular nucleus, and prominent nucleoli. INI1 immunostain was retained in all cases. We reported the rhabdoid variant of ACC, a novel entity, and its diagnostic approach from their histological mimickers. Identifying more cases of this entity will help to clearly understand the pathogenesis, biologic behaviour, and any specific molecular alterations in the future.