Identification and clinical significance of somatic oncogenic mutations in epithelial ovarian cancer.

OBJECTIVE: Epithelial ovarian cancer (EOC) is a heterogeneous disease with diverse clinicopathological features and behaviors, and its heterogeneity may be concerned with the accumulation of multiple somatic oncogenic mutations. The major goals of this study are to systematically perform the comprehensive mutational profiling in EOC patients, and investigate the associations between somatic mutations and clinicopathological characteristics. METHODS: A total of 80 surgical specimens were obtained from EOC patients who had previously undergone primary debulking surgery, and genomic DNAs were extracted from fresh-frozen tissues. We investigated mutational status in hot spot regions of 50 cancer-related genes by targeted next-generation sequencing using an Ion AmpliSeq Cancer Hotspot Panel v2 Kit. RESULTS: Validated mutations were detected in 66 of the 80 tumors (82.5%). The five most frequently mutated genes were TP53 (43.8%), PIK3CA (27.5%), KRAS (23.8%), PTEN (10%) and CTNNB1 (10%). PTEN and CTNNB1 mutations were associated with younger age. PIK3CA1, KRAS and CTNNB1 mutations were observed in early-stage, whereas TP53 mutations were more common in advanced stage. Significant associations were observed between TP53 mutation and serous carcinoma, and between KRAS mutation and mucinous carcinoma. Both PIK3CA mutation and CTNNB1 mutation were also significantly associated with endometrioid and clear cell carcinoma. The patients with PIK3CA and KRAS mutations were significantly associated with favorable progression free survival (PFS). In particular, PIK3CA mutations had more significant associations with favorable PFS than PIK3CA wild-type in the endometrioid subtype (P = 0.012). Patients with mutations only in TP53 were significantly associated with worse PFS. CONCLUSION: EOCs were heterogeneous at the genomic level and harbored somatic oncogenic mutations. Our molecular profiling may have the potential for becoming a novel stratification within histological subtypes of EOC. Further studies are needed to define molecular classification for improved clinical outcomes and treatment of EOC patients in future.

Evaluation of anticancer agents using patient-derived tumor organoids characteristically similar to source tissues.

Patient-derived tumor xenograft models represent a promising preclinical cancer model that better replicates disease, compared with traditional cell culture; however, their use is low-throughput and costly. To overcome this limitation, patient-derived tumor organoids (PDOs) were established from human lung, ovarian and uterine tumor tissues, among others, to accurately and efficiently recapitulate the tissue architecture and function. PDOs were able to be cultured for >6 months, and formed cell clusters with similar morphologies to their source tumors. Comparative histological and comprehensive gene expression analyses proved that the characteristics of PDOs were similar to those of their source tumors, even following long-term expansion in culture. At present, 53 PDOs have been established by the Fukushima Translational Research Project, and were designated as Fukushima PDOs (F­PDOs). In addition, the in vivo tumorigenesis of certain F­PDOs was confirmed using a xenograft model. The present study represents a detailed analysis of three F­PDOs (termed REME9, 11 and 16) established from endometrial cancer tissues. These were used for cell growth inhibition experiments using anticancer agents. A suitable high-throughput assay system, with 96- or 384­well plates, was designed for each F­PDO, and the efficacy of the anticancer agents was subsequently evaluated. REME9 and 11 exhibited distinct responses and increased resistance to the drugs, as compared with conventional cancer cell lines (AN3 CA and RL95-2). REME9 and 11, which were established from tumors that originated in patients who did not respond to paclitaxel and carboplatin (the standard chemotherapy for endometrial cancer), exhibited high resistance (half-maximal inhibitory concentration >10 µM) to the two agents. Therefore, assay systems using F­PDOs may be utilized to evaluate anticancer agents using conditions that better reflect clinical conditions, compared with conventional methods using cancer cell lines, and to discover markers that identify the pharmacological effects of anticancer agents.

Epidermoid cyst involving the medial temporal lobe: surgical pathologic features of the epileptogenic lesion.

Epidermoid cysts in the middle fossa are rare and may involve the temporal lobe and lateral ventricle. Affected patients often suffer from seizures, but the pathomechanisms underlying the epileptogenic lesions have remained unclear. Here we report the surgical pathological features of the hippocampus in a 31-year-old woman with mesial temporal lobe epilepsy (mTLE), in whom an epidermoid cyst involving the right basal cistern and inferior horn of the lateral ventricle was evident. The ictal electrocorticogram indicated seizure onset at the parahippocampal gyrus. An anterior temporal lobectomy and amygdalohippocampectomy were performed. Histologically, the hippocampus showed marked atrophy with severe loss of pyramidal neurons in the cornu Ammonis subfields and granule cell loss in the dentate gyrus. At the ventricular surface of the hippocampus, there were small granulomatous lesions with spicularly anchored keratin substance. These features indicated multiple and chronic stab wounds by the cyst contents and consequent local inflammatory responses within the parenchyma. The predisposition to adhesion between the tumor and hippocampus may have caused neurons to develop abnormal irritability to certain chemical mediators present in the cyst. Epileptogenicity involving the atrophic hippocampus and medial temporal lobes nearby may have developed in association with these processes. This case appears to provide information that is useful for surgical planning in patients with mTLE and epidermoid cysts involving the medial temporal lobe.

Adult-onset angiocentric glioma of epithelioid cell-predominant type of the mesial temporal lobe suggestive of a rare but distinct clinicopathological subset within a spectrum of angiocentric cortical ependymal tumors.

Angiocentric glioma (AG) is defined as an epilepsy-associated stable or slowly growing cerebral tumor primarily affecting children and young adults, histologically consisting mainly of monomorphic, bipolar spindle-shaped cells and occasional round to monopolar columnar epithelioid cells, showing angiocentric growth pattern and features of ependymal differentiation. We describe two clinicopathologically unusual cases of AG. Case 1 is a 54-year-old woman with a 10-year history of complex partial seizures. MRI revealed non-enhancing T1-low, T2/fluid-attenuated inversion recovery (FLAIR)-high intensity signal change in the left hippocampus and amygdala. After selective amygdalohippocampectomy, she had rare non-disabling seizures on medication for over 50 months (Engel's class I). Case 2 is a 37-year-old man with a 3-year history of complex partial seizures. MRI revealed non-enhancing T1-low, T2/FLAIR-high intensity signal change in the left uncus and amygdala. After combined amygdalohippocampectomy and anterior temporal lobectomy, he has been seizure-free for over 11 months. Histologically the tumors in both cases consisted mainly of infiltrating epithelioid cells (GFAP- ∼±, S-100-) with perinuclear epithelial membrane antigen (EMA)-positive dots and rings, showing conspicuous single- and multi-layered angiocentric arrangements. Occasional tumor cells showed spindle-shaped morphology (GFAP+, S-100+) with rare EMA-positive dots aligned radially and longitudinally along parenchymal blood vessels. Focal solid areas showed a Schwannoma-like fascicular arrangement with rare EMA-positive dots and/or sheets of epithelioid cells with abundant EMA dots. Electron microscopic investigation demonstrated features of ependymal differentiation. These cases, together with a few similar cases previously reported, appear to represent a rare but distinct clinicopathological subset of AG characterized by adult-onset, mesial temporal lobe localization and epithelioid cell-predominant histology.

Spatiotemporal dynamics of epileptiform propagations: imaging of human brain slices.

Seizure activities often originate from a localized region of the cerebral cortex and spread across large areas of the brain. The properties of these spreading abnormal discharges may account for clinical phenotypes in epilepsy patients, although the manner of their propagation and the underlying mechanisms are not well understood. In the present study we performed flavoprotein fluorescence imaging of cortical brain slices surgically resected from patients with partial epilepsy caused by various symptomatic lesions. Elicited neural activities in the epileptogenic tissue spread horizontally over the cortex momentarily, but those in control tissue taken from patients with brain tumors who had no history of epilepsy demonstrated only localized responses. Characteristically, the epileptiform propagation comprised early and late phases. When the stimulus intensity was changed gradually, the early phase showed an all-or-none behavior, whereas the late phase showed a gradual increase in the response. Moreover, the two phases were propagated through different cortical layers, suggesting that they are derived from distinct neural circuits. Morphological investigation revealed the presence of hypertrophic neurons and loss of dendritic spines, which might participate in the aberrant activities observed by flavoprotein fluorescence imaging. These findings indicate that synchronized activities of the early phase may play a key role in spreading abnormal discharges in human cortical epilepsies.

Balloon cells in the dentate gyrus in hippocampal sclerosis associated with non-herpetic acute limbic encephalitis.

The presence of balloon cells, a pathognomonic cellular feature of focal cortical dysplasia type IIB, in a background of hippocampal sclerosis is rare. Here we report the surgical pathologic features of the hippocampus resected from a 32-year-old woman with mesial temporal lobe epilepsy and a precipitating history of non-herpetic acute limbic encephalitis. Histologically, the resected specimen showed features of hippocampal sclerosis with granule cell dispersion. Characteristically, many balloon cells, immunoreactive for nestin, vimentin, glial fibrillary acidic protein (GFAP), GFAP-delta and CD34, were observed in the molecular and granule cell layers of the dentate gyrus. In the present case hippocampal sclerosis was an apparently acquired alteration, rather than a result of maldevelopment. The appearance of balloon cells raises questions regarding their origin and morphogenesis.