Genomic profiling identifies GPC5 amplification in association with sarcomatous transformation in a subset of uterine carcinosarcomas

Genomics of gynaecological carcinosarcomas and future treatment options

Gynaecological carcinosarcomas are the most lethal gynaecological malignancies that are often highly resistant to standard chemotherapy. They are composed of both carcinomatous and sarcomatous components and are associated with high rates of metastatic disease. Due to their rarity, molecular studies have been carried out on relatively few tumours, revealing a broad spectrum of heterogeneity. In this review, we have collated the gene mutations, gene expression, epigenetic regulation and protein expression reported by a number of studies on gynaecological carcinosarcomas. Based on these results, we describe potential therapeutics that may demonstrate efficacy and present any pre-clinical studies that have been carried out. We also describe the pre-clinical models currently available for future research to assess the potential of molecularly matched therapies. Interestingly, over-expression of many biomarkers in carcinosarcoma tumours often doesn't correlate with a worse prognosis. Therefore, we propose that profiling the mutational landscape, gene expression, and gene amplification/deletion may better indicate potential treatment strategies and predict response, thus improving outcomes for women with this rare, aggressive disease.

Molecular profiling of the biphasic components of hepatic carcinosarcoma by the use of targeted next-generation sequencing

AIMS

To better understand the tumourogenesis and molecular features of hepatic carcinosarcoma (HCS).

METHODS AND RESULTS

We selected 13 cases of HCS, including the clinicopathological and immunohistochemical features, and analysed the molecular alterations in separately microdissected carcinomatous and sarcomatous components in eight cases by using targeted next-generation sequencing with a panel of 329 cancer-related genes. As a result, transitional areas were observed between the two components of HCS in all cases. Concordance and overlap in genetic alterations were identified in the two histological components of the eight HCS patients, indicating the clonal relatedness of the two tumour components. The most common gene alterations found in both components were TP53 (75%, 6/8) and NF1/2 (38%, 3/8) mutations and VEGFA amplification (25%, 2/8), which may be strongly associated with HCS tumorigenesis. Unique mutations and amplifications found only in one component were also identified. Amplifications involving MET (38%, n = 3/8) and PDGFRA (25%, n = 2/8) were present only in the sarcomatous components, whereas mutation affecting ERBB4 (25%, n = 2/8) and amplifications of CCND1 and FGF3/4/19 (38%, n = 3/8) were present only in the carcinomatous components, indicating their involvement in the clonal evolution of HCS. Furthermore, multiple potential therapeutic targets were identified for HCS.

CONCLUSIONS

Our findings indicate that HCS could have been of monoclonal origin, and that the diverse clonal evolution might be driven by special molecular alterations in each tumour component. Our results also identify multiple therapeutic targets of HCS, which are valuable for the personalised treatment of HCS.

Molecular Basis of Tumor Heterogeneity in Endometrial Carcinosarcoma

Endometrial carcinosarcoma (ECS) represents one of the most extreme examples of tumor heterogeneity among human cancers. ECS is a clinically aggressive, high-grade, metaplastic carcinoma. At the morphological level, intratumor heterogeneity in ECS is due to an admixture of epithelial (carcinoma) and mesenchymal (sarcoma) components that can include heterologous tissues, such as skeletal muscle, cartilage, or bone. Most ECSs belong to the copy-number high serous-like molecular subtype of endometrial carcinoma, characterized by the TP53 mutation and the frequently accompanied by a large number of gene copy-number alterations, including the amplification of important oncogenes, such as CCNE1 and c-MYC. However, a proportion of cases (20%) probably represent the progression of tumors initially belonging to the copy-number low endometrioid-like molecular subtype (characterized by mutations in genes such as PTEN, PI3KCA, or ARID1A), after the acquisition of the TP53 mutations. Only a few ECS belong to the microsatellite-unstable hypermutated molecular type and the POLE-mutated, ultramutated molecular type. A common characteristic of all ECSs is the modulation of genes involved in the epithelial to mesenchymal process. Thus, the acquisition of a mesenchymal phenotype is associated with a switch from E- to N-cadherin, the up-regulation of transcriptional repressors of E-cadherin, such as Snail Family Transcriptional Repressor 1 and 2 (SNAI1 and SNAI2), Zinc Finger E-Box Binding Homeobox 1 and 2 (ZEB1 and ZEB2), and the down-regulation, among others, of members of the miR-200 family involved in the maintenance of an epithelial phenotype. Subsequent differentiation to different types of mesenchymal tissues increases tumor heterogeneity and probably modulates clinical behavior and therapy response.

MicroRNA-301b promotes the proliferation and invasion of glioma cells through enhancing activation of Wnt/β-catenin signaling via targeting Glypican-5

Accumulating evidence has suggested that Glypican-5 (GPC5) is a tumor suppressor gene in many types of cancers. However, whether GPC5 is involved in glioma remains unknown. This study was designed to explore the expression, biological function and regulatory mechanism of GPC5 in glioma. Our results demonstrated that GPC5 expression was significantly decreased in multiple glioma cell lines. Gain-of-function experiments showed that the ectopic expression of GPC5 markedly inhibited the proliferation, invasion and Wnt/β-catenin signaling of glioma cell lines. GPC5 was identified as a target gene of microRNA-301b (miR-301b). Further data showed that miR-301b expression was significantly up-regulated in glioma tissues and cell lines. In addition, miR-301b expression was inversely correlated with GPC5 expression in clinical glioma tissues. The overexpression of miR-301b promoted the proliferation, invasion and Wnt/β-catenin signaling of glioma cell lines, whereas the inhibition of miR-301b showed the opposite effect. However, the silencing of GPC5 significantly reversed the antitumor effect of miR-301b inhibition. Overall, our results revealed a tumor suppressive role of GPC5 in glioma and suggested that GPC5 expression was regulated by miR-301b. Our study indicates that the inhibition of miR-301b represses the proliferation and invasion of glioma cells by up-regulating GPC5 expression.

A 4-gene panel predicting the survival of patients with glioblastoma

BACKGROUND

To identify independently prognostic gene panel in patients with glioblastoma (GBM).

MATERIALS AND METHODS

The Cancer Genome Atlas (TCGA)-GBM was used as a training set and a test set. GSE13041 was used as a validation set. Survival associated differentially expression genes (DEGs), derived between GBM and normal brain tissue, was obtained using univariate Cox proportional hazards regression model and then was included in a least absolute shrinkage and selection operator penalized Cox proportional hazards regression model. Thus, a 4-gene prognostic panel was developed based on the risk score for each patient in that model. The prognostic role of the 4-gene panel was validated using univariate and multivariable Cox proportional hazards regression model.

RESULTS

A total of 686 patients with GBM were included in our study; 724 DEGs was identified, 133 of which was significantly correlated with the overall survival (OS) of patients with GBM. A 4-gene panel including NMB, RTN1, GPC5, and epithelial membrane protein 3 (EMP3) was developed. Kaplan-Meier survival analysis suggested that patients in the 4-gene panel low risk group had significantly better OS than those in the 4-gene panel high risk group in the training set (hazard ratio [HR] = 0.3826; 95% confidence interval [CI]: 0.2751-0.532; P < 0.0001), test set (HR = 0.718; 95% CI: 0.5282-0.9759; P = 0.033) and the independent validation set (HR = 0.6898; 95% CI: 0.4872-0.9766; P = 0.035). Both univariate and multivariable Cox proportional hazards regression analysis suggested that the 4-gene panel was independent prognostic factor for GBM in the training set.

CONCLUSION

We developed and validated 4-gene panel that was independently correlated with the survival of patients with GBM.