Chang Ohk Sung

Genomic portrait of resectable hepatocellular carcinomas: implications of RB1 and FGF19 aberrations for patient stratification.

Hepatic resection is the most curative treatment option for early‐stage hepatocellular carcinoma, but is associated with a high recurrence rate, which exceeds 50% at 5 years after surgery. Understanding the genetic basis of hepatocellular carcinoma at surgically curable stages may enable the identification of new molecular biomarkers that accurately identify patients in need of additional early therapeutic interventions. Whole exome sequencing and copy number analysis was performed on 231 hepatocellular carcinomas (72% with hepatitis B viral infection) that were classified as early‐stage hepatocellular carcinomas, candidates for surgical resection. Recurrent mutations were validated by Sanger sequencing. Unsupervised genomic analyses identified an association between specific genetic aberrations and postoperative clinical outcomes. Recurrent somatic mutations were identified in nine genes, including TP53, CTNNB1, AXIN1, RPS6KA3, and RB1. Recurrent homozygous deletions in FAM123A, RB1, and CDKN2A, and high‐copy amplifications in MYC, RSPO2, CCND1, and FGF19 were detected. Pathway analyses of these genes revealed aberrations in the p53, Wnt, PIK3/Ras, cell cycle, and chromatin remodeling pathways. RB1 mutations were significantly associated with cancer‐specific and recurrence‐free survival after resection (multivariate P = 0.038 and P = 0.012, respectively). FGF19 amplifications, known to activate Wnt signaling, were mutually exclusive with CTNNB1 and AXIN1 mutations, and significantly associated with cirrhosis (P = 0.017). Conclusion: RB1 mutations can be used as a prognostic molecular biomarker for resectable hepatocellular carcinoma. Further study is required to investigate the potential role of FGF19 amplification in driving hepatocarcinogenesis in patients with liver cirrhosis and to investigate the potential of anti‐FGF19 treatment in these patients. (Hepatology 2014;60:1971–1981)

Clinical relevance of gain-of-function mutations of p53 in high-grade serous ovarian carcinoma.

Purpose Inactivation of TP53, which occurs predominantly by missense mutations in exons 4–9, is a major genetic alteration in a subset of human cancer. In spite of growing evidence that gain-of-function (GOF) mutations of p53 also have oncogenic activity, little is known about the clinical relevance of these mutations. Methods The clinicopathological features of high-grade serous ovarian carcinoma (HGS-OvCa) patients with GOF p53 mutations were evaluated according to a comprehensive somatic mutation profile comprised of whole exome sequencing, mRNA expression, and protein expression profiles obtained from the Cancer Genome Atlas (TCGA). Results Patients with a mutant p53 protein (mutp53) with a GOF mutation showed higher p53 mRNA and protein expression levels than patients with p53 mutation with no evidence of GOF (NE-GOF). GOF mutations were more likely to occur within mutational hotspots, and at CpG sites, and resulted in mutp53 with higher functional severity (FS) scores. Clinically, patients with GOF mutations showed a higher frequency of platinum resistance (22/58, 37.9%) than patients with NE-GOF mutations (12/56, 21.4%) (p=0.054). Furthermore, patients with GOF mutations were more likely to develop distant metastasis (36/55, 65.5%) than local recurrence (19/55, 34.5%), whereas patients with NE-GOF mutations showed a higher frequency of locoregional recurrence (26/47, 55.3%) than distant metastasis (21/47, 44.7%) (p=0.035). There were no differences in overall or progression-free survival between patients with GOF or NE-GOF mutp53. Conclusion This study demonstrates that patient with GOF mutp53 is characterized by a greater likelihood of platinum treatment resistance and distant metastatic properties in HGS-OvCa.

Accuracy of Core Needle Biopsy Versus Fine Needle Aspiration Cytology for Diagnosing Salivary Gland Tumors

Background: Core needle biopsy is a relatively new technique used to diagnose salivary gland lesions, and its role in comparison with fine needle aspiration cytology needs to be refined. Methods: We compared the results of 228 ultrasound-guided core needle biopsy and 371 fine needle aspiration procedures performed on major salivary gland tumors with their postoperative histological diagnoses. Results: Core needle biopsy resulted in significantly higher sensitivity and more accurate tumor subtyping, especially for malignant tumors, than fine needle aspiration. No patient developed major complications after core needle biopsy. Conclusions: We recommend ultrasoundguided core needle biopsy as the primary diagnostic tool for the preoperative evaluation of patients with salivary gland lesions, especially when malignancy is suspected.

High throughput molecular profiling reveals differential mutation patterns in intrahepatic cholangiocarcinomas arising in chronic advanced liver diseases

Intrahepatic cholangiocarcinomas occur mostly in the normal liver but they also arise in chronic advanced liver diseases. However, genetic differences between two groups have yet to be examined. High throughput mass spectrometry-based platform was used to interrogate mutations in intrahepatic cholangiocarcinomas and to compare the mutation profiles between 43 intrahepatic cholangiocarcinomas with normal liver and 38 with chronic advanced liver diseases. Forty seven mutations in 11 genes were identified in 38 of 81 cases (46.9%). The most commonly mutated gene was KRAS (11/81, 13.6%), followed by MLH1 (7/81, 8.6%), NRAS (7/81, 8.6%), GNAS (6/81, 7.4%), and EGFR (6/81, 7.4%). BRAF, APC, PIK3CA, CDKN2A, PTEN, and TP53 mutations were found with less than 5%. Overall mutation rate of intrahepatic cholangiocarcinomas with chronic advanced liver disease (15/38, 39.5%, 95% confidence interval: 23.9–55.0) was lower than that of intrahepatic cholangiocarcinomas with normal liver (23/43, 53.5%, 95% confidence interval: 38.5–68.3). Intrahepatic cholangiocarcinomas with chronic advanced liver disease showed higher EGFR mutation rate (5/38, 13.2% vs 1/43, 2.3%) and lower mutation rates of KRAS (3/38, 7.9% vs 8/43, 18.6%), MLH1 (2/38, 5.3% vs 5/43, 11.6%), and GNAS (1/38, 2.6% vs 5/43, 11.6%), compared with those in intrahepatic cholangiocarcinomas with normal liver. Mutations in PIK3CA, PTEN, CDKN2A, and TP53 were harbored only in intrahepatic cholangiocarcinomas with normal liver. KRAS (P=0.0075) or GNAS mutations (P=0.0256) were associated with poor overall survival in all patients with intrahepatic cholangiocarcinoma. Differential mutation patterns of intrahepatic cholangiocarcinomas with chronic advanced liver disease suggest different cholangiocarcinogenesis depending upon the predisposing factors, and support that different strategy for targeted therapy should be applied in intrahepatic cholangiocarcinoma subtypes.

BRAF V600E mutations are frequent in dysembryoplastic neuroepithelial tumors and subependymal giant cell astrocytomas

BRAF mutation has received a great deal of attention in neuro‐oncology field, recently. This study aimed to investigate the incidence and the clinical significance of BRAFV600E in low‐grade glial tumors.

TWIST1 promoter methylation is associated with prognosis in tonsillar squamous cell carcinoma.

Tonsillar squamous cell carcinomas (TSCC) frequently present with locally advanced diseases and cervical metastases, which are associated with poor prognoses. Epithelial-mesenchymal transition (EMT) is critical for tumor invasiveness and metastatic potential. Recent studies have shown that TWIST1-inducing EMT is overexpressed and hypermethylated in several cancers, indicating disease progression. The aim of the present study was to determine the clinical and prognostic significance of TWIST1 hypermethylation and EMT-related protein expression in TSCC. Methylation levels of TWIST1 promoter were analyzed by quantitative real-time methylation-specific polymerase chain reaction. Immunohistochemical analyses of TWIST1, Snail, and SMAD nuclear interacting protein-1 (SNIP1) were performed in 65 formalin-fixed, paraffin-embedded blocks of surgically resected specimens. TWIST1 promoter hypermethylation was found in 27.7% (18/65) of TSCCs. TWIST1 promoter hypermethylation was associated with poor differentiation (P = .012). Contralateral cervical lymph node metastasis was more frequently observed in TWIST1-methylated tumors (P = .029). High protein expressions of TWIST1, Snail, and SNIP1 were observed in 14 TSCC specimens (21.5%), 21 TSCC specimens (32.3%), and 38 TSCC specimens (58.5%), respectively. SNIP1 expression correlated significantly with TWIST1 methylation (P = .001), whereas TWIST1 protein expression did not. Contralateral cervical lymph node metastasis was an independent risk factor of the decreased overall survival rate (P = .002). TWIST1 methylation (P = .031) and pN stage (P = .037) were independent factors of poor prognoses affecting disease-free survival. TWIST1 promoter hypermethylation may be a useful molecular marker for predicting prognoses and contralateral cervical lymph node metastases in patients with TSCC.

Predictive Modeling Using a Somatic Mutational Profile in Ovarian High Grade Serous Carcinoma

Purpose Recent high-throughput sequencing technology has identified numerous somatic mutations across the whole exome in a variety of cancers. In this study, we generate a predictive model employing the whole exome somatic mutational profile of ovarian high-grade serous carcinomas (Ov-HGSCs) obtained from The Cancer Genome Atlas data portal. Methods A total of 311 patients were included for modeling overall survival (OS) and 259 patients were included for modeling progression free survival (PFS) in an analysis of 509 genes. The model was validated with complete leave-one-out cross-validation involving re-selecting genes for each iteration of the cross-validation procedure. Cross-validated Kaplan-Meier curves were generated. Cross-validated time dependent receiver operating characteristic (ROC) curves were computed and the area under the curve (AUC) values were calculated from the ROC curves to estimate the predictive accuracy of the survival risk models. Results There was a significant difference in OS between the high-risk group (median, 28.1 months) and the low-risk group (median, 61.5 months) (permutated p-value <0.001). For PFS, there was also a significant difference in PFS between the high-risk group (10.9 months) and the low-risk group (22.3 months) (permutated p-value <0.001). Cross-validated AUC values were 0.807 for the OS and 0.747 for the PFS based on a defined landmark time t = 36 months. In comparisons between a predictive model containing only gene variables and a combined model containing both gene variables and clinical covariates, the predictive model containing gene variables without clinical covariates were effective and high AUC values for both OS and PFS were observed. Conclusions We designed a predictive model using a somatic mutation profile obtained from high-throughput genomic sequencing data in Ov-HGSC samples that may represent a new strategy for applying high-throughput sequencing data to clinical practice.

A distinctive ovarian cancer molecular subgroup characterized by poor prognosis and somatic focal copy number amplifications at chromosome 19

OBJECTIVE High-grade serous ovarian cancer (HGS-OvCa), the most common epithelial ovarian cancer, is very complex and heterogeneous at the molecular level. The identification of intrinsic HGS-OvCa subgroups characterized by specific molecular alterations and aggressive behavior could improve patient treatment. METHODS High-resolution copy number data for 560 HGS-OvCa patients and gene expression data obtained from the TCGA database were analyzed to identify distinct molecular subgroups based on significant focal somatic copy number alterations (SCNAs). RESULTS Using unsupervised consensus clustering, a subgroup accounting for 26.8% of the patients (150/560 patients) characterized by focal somatic copy number amplification at chromosome 19 was identified. The subgroup was independently associated by multivariate Cox regression analysis with poor overall (HR, 1.61; P = 0.001) and progression-free survival (HR, 1.36; P = 0.036). The specific focal SCNA locations were 19p13.2, 19p13.12, 19p13.11, 19q12, 19q13.12, and 19q13.2. The differential gene expression signature of the subgroup compared with that of the remaining patients also suggested that chromosome 19 was the mainly amplified region. The clinical significances of subgroup 2 were validated in independent data sets using the gene expression signature characteristics. In addition, the subgroup had a tendency toward mutual exclusivity with patients with BRCA1/2 mutations. The most significantly altered pathway of the subgroup was the cyclin and cell cycle regulation pathway. CONCLUSION A unique molecular subgroup associated with poor survival was identified based on focal SCNAs and could aid the further molecular classification of ovarian cancers.

Overexpression of C-reactive Protein as a Poor Prognostic Marker of Resectable Hepatocellular Carcinomas

Background: C-reactive protein (CRP) is an acute phase reactant synthesized in the liver. CRP immunoreactivity is a feature of inflammatory hepatocellular adenomas with a higher risk of malignant transformation. A high serum CRP level denotes poor prognosis in hepatocellular carcinoma (HCC) patients. This study was conducted to determine whether CRP is produced in HCC and to assess the clinicopathologic significance of CRP expression in cancer cells. Methods: CRP immunoreactivity was examined in treatment-naïve HCCs (n=224) using tissue microarrays and was correlated with clinicopathologic parameters. The expression of CRP mRNA and protein was also assessed in 12 HCC cases by quantitative real-time polymerase chain reaction and immunoblotting. Hep3B and SNU-449 HCC cell lines were used for the analysis of CRP mRNA regulation by interleukin 6 (IL-6). Results: CRP was expressed in 133 of 224 HCCs (59.4%) with a variable degree of immunoreactivity (grade 1 in 25.9%; grade 2 in 20.1%; grade 3 in 13.4%). There was an inverse relationship between grade 3 CRP immunoreactivity and cancer-specific survival (p=.0047), while no associations were found with other parameters, including recurrence-free survival. The CRP mRNA expression level was significantly higher in CRP immunopositive cases than in immunonegative cases (p<.05). CRP mRNA expression was increased in Hep3B cells, but was not detected in SNU-449 cells even after IL-6 treatment. Conclusions: We report the expression of CRP in HCC for the first time. CRP expression was associated with poor cancer-specific survival in patients with resectable HCC.

Differential expression of extracellular matrix-related genes in rare variants of meningioma.

Secretory, clear cell, and rhabdoid meningiomas are rare variants of meningiomas characterized by unique histologies and behaviors. Extracellular matrix proteins provide a morphologic structure and influence the biologic behavior of tumors. However, the effects of extracellular matrix proteins on morphologies and biologic behaviors of secretory meningioma, clear cell meningioma, and rhabdoid meningioma have not been established. We evaluated the expression of matrix metalloproteinase 2, matrix metalloproteinase 9, galectin-3, fibronectin, and collagen IV in a series of those rare variants of meningioma and verified their clinicopathologic significance. A total 51 cases included 12 secretory meningiomas, 9 clear cell meningiomas, and 30 rhabdoid meningiomas. Extracellular matrix proteins showed different expression patterns according to the histologic subtypes, and messenger RNA levels were well correlated with immunoexpressions. Secretory meningiomas showed high expressions of fibronectin and galectin-3. Clear cell meningiomas showed high expression of matrix metalloproteinase 2, matrix metalloproteinase 9, and collagen IV. Rhabdoid meningiomas showed high expressions of matrix metalloproteinase 9, galectin-3, and fibronectin. Clinically, high expression of matrix metalloproteinase 9 was associated with tumor recurrence (P < .001) and local invasion at the time of diagnosis (P = .018) among the extracellular matrix-related proteins, and was also associated with shorter recurrence-free survival (P = .025) in the patients with rhabdoid meningioma. In conclusion, the differential expressions of extracellular matrix-related genes according to the histologic subtypes appear to be involved in biologic behavior and clinical outcome, and high matrix metalloproteinase 9 expression is associated with recurrences in rhabdoid meningiomas.