Study of sex-biased differences in genomic profiles in East Asian hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is characterized by a notable sex disparity in incidence and tumor aggressiveness. Revealing differences in genetic landscapes between male and female HCCs may expand the understanding of sexual disparities mechanisms and assist the development of precision medicine. Although reports on the sex disparity of HCC are accumulated, studies focusing on sex-related biomarkers among Asian populations remain limited. Here, we conducted a comprehensive genomic profiling analysis to explore differences between male and female patients within a cohort of 195 Taiwanese HCC patients. We did not detect any sex-biased genomic alterations. However, when our investigation extended to the TCGA dataset, we found higher frequencies of gene copy gains in CCNE2 and mutations in CTNNB1 and TP53 among male patients. Besides, we further evaluated the associations between genomic alterations and patients' prognosis by sex. The results showed that female patients harboring tumors with STAT3 gain and alterations in the JAK-STAT pathway displayed a poor prognosis. These two factors remained independently associated with unfavorable prognosis even after adjusting for the patient's age and stage characteristics (Hazard ratio = 10.434, 95% CI 3.331-32.677, P < 0.001; Hazard ratio = 2.547, 95% CI 1.195-5.432, P = 0.016, respectively). In summary, this study provides valuable insights into understanding sex disparity in HCC in the East Asian population. Validation through larger cohorts and extensive sequencing efforts is warranted.

Comprehensive genomic profiling and therapeutic implications for Taiwanese patients with treatment-naïve breast cancer.

BACKGROUND: Breast cancer is a heterogeneous disease categorized based on molecular characteristics, including hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) expression levels. The emergence of profiling technology has revealed multiple driver genomic alterations within each breast cancer subtype, serving as biomarkers to predict treatment outcomes. This study aimed to explore the genomic landscape of breast cancer in the Taiwanese population through comprehensive genomic profiling (CGP) and identify diagnostic and predictive biomarkers. METHODS: Targeted next-generation sequencing-based CGP was performed on 116 archived Taiwanese breast cancer specimens, assessing genomic alterations (GAs), including single nucleotide variants, copy number variants, fusion genes, tumor mutation burden (TMB), and microsatellite instability (MSI) status. Predictive variants for FDA-approved therapies were evaluated within each subtype. RESULTS: In the cohort, frequent mutations included PIK3CA (39.7%), TP53 (36.2%), KMT2C (9.5%), GATA3 (8.6%), and SF3B1 (6.9%). All subtypes had low TMB, with no MSI-H tumors. Among HR + HER2- patients, 42% (27/65) harbored activating PIK3CA mutations, implying potential sensitivity to PI3K inhibitors and resistance to endocrine therapies. HR + HER2- patients exhibited intrinsic hormonal resistance via FGFR1 gene gain/amplification (15%), exclusive of PI3K/AKT pathway alterations. Aberrations in the PI3K/AKT/mTOR and FGFR pathways were implicated in chemoresistance, with a 52.9% involvement in triple-negative breast cancer. In HER2+ tumors, 50% harbored GAs potentially conferring resistance to anti-HER2 therapies, including PIK3CA mutations (32%), MAP3K1 (2.9%), NF1 (2.9%), and copy number gain/amplification of FGFR1 (18%), FGFR3 (2.9%), EGFR (2.9%), and AKT2 (2.9%). CONCLUSION: This study presents CGP findings for treatment-naïve Taiwanese breast cancer, emphasizing its value in routine breast cancer management, disease classification, and treatment selection.

A gender-specific association of CNV at 6p21.3 with NPC susceptibility.

Copy number variations (CNVs), a major source of human genetic polymorphism, have been suggested to have an important role in genetic susceptibility to common diseases such as cancer, immune diseases and neurological disorders. Nasopharyngeal carcinoma (NPC) is a multifactorial tumor closely associated with genetic background and with a male preponderance over female (3:1). Previous genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) that are associated with NPC susceptibility. Here, we sought to explore the possible association of CNVs with NPC predisposition. Utilizing genome-wide SNP-based arrays and five CNV-prediction algorithms, we identified eight regions with CNV that were significantly overrepresented in NPC patients compared with healthy controls. These CNVs included six deletions (on chromosomes 3, 6, 7, 8 and 19), and two duplications (on chromosomes 7 and 12). Among them, the CNV located at chromosome 6p21.3, with single-copy deletion of the MICA and HCP5 genes, showed the highest association with NPC. Interestingly, it was more specifically associated with an increased NPC risk among males. This gender-specific association was replicated in an independent case-control sample using a self-established deletion-specific polymerase chain reaction strategy. To the best of our knowledge, this is the first study to explore the role of constitutional CNVs in NPC, using a genome-wide platform. Moreover, we identified eight novel candidate regions with CNV that merit future investigation, and our results suggest that similar to neuroblastoma and prostate cancer, genetic structural variations might contribute to NPC predisposition.

Genome-wide association study reveals multiple nasopharyngeal carcinoma-associated loci within the HLA region at chromosome 6p21.3.

Nasopharyngeal carcinoma (NPC) is a multifactorial malignancy closely associated with genetic factors and Epstein-Barr virus infection. To identify the common genetic variants linked to NPC susceptibility, we conducted a genome-wide association study (GWAS) in 277 NPC patients and 285 healthy controls within the Taiwanese population, analyzing 480,365 single-nucleotide polymorphisms (SNPs). Twelve statistically significant SNPs were identified and mapped to chromosome 6p21.3. Associations were replicated in two independent sets of case-control samples. Two of the most significant SNPs (rs2517713 and rs2975042; p(combined) = 3.9 x 10(-20) and 1.6 x 10(-19), respectively) were located in the HLA-A gene. Moreover, we detected significant associations between NPC and two genes: specifically, gamma aminobutyric acid b receptor 1 (GABBR1) (rs29232; p(combined) = 8.97 x 10(-17)) and HLA-F (rs3129055 and rs9258122; p(combined) = 7.36 x 10(-11) and 3.33 x 10(-10), respectively). Notably, the association of rs29232 remained significant (residual p < 5 x 10(-4)) after adjustment for age, gender, and HLA-related SNPs. Furthermore, higher GABA(B) receptor 1 expression levels can be found in the tumor cells in comparison to the adjacent epithelial cells (p < 0.001) in NPC biopsies, implying a biological role of GABBR1 in NPC carcinogenesis. To our knowledge, it is the first GWAS report of NPC showing that multiple loci (HLA-A, HLA-F, and GABBR1) within chromosome 6p21.3 are associated with NPC. Although some of these relationships may be attributed to linkage disequilibrium between the loci, the findings clearly provide a fresh direction for the study of NPC development.

Genomic characterization reveals potential biomarkers in nasopharyngeal carcinoma patients with relapse.

BACKGROUND: Although the majority of nasopharyngeal carcinoma (NPC) patients demonstrate favorable outcomes after radiotherapy and/or chemotherapy, about 8-10% of patients will develop recurrent disease, and genomic alterations (GAs) associated with the recurrence are unclear. METHODS: This study investigated the GAs in the paired primary tumors and recurrent tumors of 7 NPC patients with relapse, as well as the primary tumors of 15 NPC patients without relapse by deep targeted next-generation sequencing on 440 cancer-related genes. RESULTS: BRCA1 and TP53 mutations were significantly enriched in patients with relapse (P = 0.021 and P = 0.023, respectively). Survival analysis revealed that the GAs of TP53, ZNF217, VEGFB, CDKN1B, GNAS, PRDM1, and MEN1 were associated with significantly shorter overall survival. The GAs of the tumor also altered after treatment in the relapsed group, and five genes (CDK4, FGFR3, ALK, BRCA1, and CHEK2) in the recurrent tumors were potentially druggable. CONCLUSIONS: The discovery of GAs associated with recurrence or survival in NPC may serve as potential prognostic gene signatures of high-risk patients. Targeted therapies are available in some of the clinically relevant GAs and may be considered in future clinical trials. Given the limitation of the sample size, validation by a larger cohort is warranted.

MCP-1 Promoter Polymorphism at 2518 is associated with metastasis of nasopharyngeal carcinoma after treatment.

PURPOSE: We herein examined whether the single nucleotide polymorphism (SNP) at -2518 of the MCP-1 gene promoter region influences clinical outcomes among nasopharyngeal carcinoma (NPC) patients. EXPERIMENTAL DESIGN: The study population consisted of 411 NPC patients without metastasis at diagnosis. All patients were treated at the Chang Gung Memorial Hospital from March 1994 to November 2004. The MCP-1 SNP-2518 genotype of each patient was determined by TaqMan genotyping kit. Statistical analyses were conducted to compare disease-specific survival (DSS), progression-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) of patients according to genotype. MCP-1 expression in tumor biopsies was examined by immunohistochemistry. RESULTS: Among 411 NPC patients, carriers of AA and AG genotypes were prone to distant metastasis than that of GG genotype (hazard ratio, 2.21; P = 0.017, and hazard ratio, 2.23; P = 0.005, for AA and AG genotype, respectively) after initial radiotherapy. No genotype-specific significant difference was found in DSS, PFS, and LRFS. Furthermore, immunohistochemistry revealed that MCP-1 expression level was higher in NPC tumor cells from GG carriers compared with those from AA and AG carriers. CONCLUSIONS: MCP-1 SNP-2518 may be a valuable genetic marker for assessing the risk of developing distant metastasis after the radiotherapy in NPC patients. Carriers of A allele may require more aggressive chemotherapy implicating a potential marker for personalized medicine. We speculate that a regulatory SNP may be associated with the distant metastasis of NPC. Validation studies are warranted.

Activation of DNA methyltransferase 1 by EBV LMP1 Involves c-Jun NH(2)-terminal kinase signaling.

EBV latent membrane protein 1 (LMP1) activates cellular DNA methyltransferases, resulting in hypermethylation and silencing of E-cadherin. However, the underlying mechanism remains to be elucidated. In this study, we show that LMP1 directly induces the dnmt1 promoter activity through its COOH-terminal activation region-2 YYD domain. Using (i) LMP1 mutants, (ii) dominant negative mutants c-jun NH(2)-terminal kinase (JNK)-DN, p38-DN, and constitutive active mutant IkappaB, as well as (iii) dsRNAs targeting c-Jun, JNK, and tumor necrosis factor receptor-associated death domain protein, and (iv) signal transduction inhibitors, we show that LMP1-mediated DNA methyltransferase-1 (DNMT1) activation involves JNK but not nuclear factor kappaB and p38/mitogen-activated protein kinase signaling. In addition, LMP1 is unable to activate dnmt1-P1 promoter with activator protein-1 (AP-1) site mutation. Chromatin immunoprecipitation assay results also confirm that LMP1 activates P1 promoter via the JNK-AP-1 pathway. Furthermore, chromatin immunoprecipitation assay data in LMP1-inducible cells disclose that LMP1 induces formation of a transcriptional repression complex, composed of DNMT1 and histone deacetylase, which locates on E-cadherin gene promoter. Treatment with JNK inhibitor, SP600125, prevents the formation of this repression complex. Statistical analyses of the immunohistochemical staining of 32 nasopharyngeal carcinoma (NPC) biopsies show LMP1 expression (18 of 32, 56.25%), DNMT1 expression (31 of 32, 97%), and phospho-c-Jun (27 of 32, 84.38%), suggesting that overexpression of these proteins is observed in NPC tumor. Overall, these results support a mechanistic link between JNK-AP-1 signaling and DNA methylation induced by the EBV oncogene product LMP1.

Modulation of Epstein-Barr virus latent membrane protein 1 activity by intrabodies.

OBJECTIVE: The Epstein-Barr virus (EBV) has been implicated in the development of many human neoplasias including B lymphoma and nasopharyngeal carcinoma. EBV latent membrane protein 1 (LMP1) is essential to virus-induced B cell immortalization and the downregulation of cell adhesion molecules that increases cell motility. Therefore, identifying LMP1 activity modulation methods may lead to the development of new therapies for LMP1-positive tumors. METHODS: This study uses a phage display single-chain variable fragments (scFvs) library to screen recombinant antibodies specific to the LMP1 C terminal region. A total of 45 individual clones were obtained, and these scFvs were cloned as intrabodies and transfected into LMP1-positive cells. RESULTS: One of the scFv clones, designated H3, was capable of reducing LMP1-mediated NF-kappaB activation in HEK293 cells. Immunofluorescence and co-immunoprecipitation studies show that scFv H3 could interact with LMP1 in vivo. In addition, expression of scFv H3 intrabody could reduce cell motility in MDCK-LMP1 cells in the transwell migration assay. CONCLUSION: These data indicate that scFv H3 intrabody can inhibit LMP1 functions in epithelial cells and may be useful for attenuating the LMP1 function in LMP1-positive tumors.

A GWAS Meta-analysis and Replication Study Identifies a Novel Locus within CLPTM1L/TERT Associated with Nasopharyngeal Carcinoma in Individuals of Chinese Ancestry.

BACKGROUND: Genetic loci within the major histocompatibility complex (MHC) have been associated with nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-associated cancer, in several GWAS. Results outside this region have varied. METHODS: We conducted a meta-analysis of four NPC GWAS among Chinese individuals (2,152 cases; 3,740 controls). Forty-three noteworthy findings outside the MHC region were identified and targeted for replication in a pooled analysis of four independent case-control studies across three regions in Asia (4,716 cases; 5,379 controls). A meta-analysis that combined results from the initial GWA and replication studies was performed. RESULTS: In the combined meta-analysis, rs31489, located within the CLPTM1L/TERT region on chromosome 5p15.33, was strongly associated with NPC (OR = 0.81; P value 6.3 × 10(-13)). Our results also provide support for associations reported from published NPC GWAS-rs6774494 (P = 1.5 × 10(-12); located in the MECOM gene region), rs9510787 (P = 5.0 × 10(-10); located in the TNFRSF19 gene region), and rs1412829/rs4977756/rs1063192 (P = 2.8 × 10(-8), P = 7.0 × 10(-7), and P = 8.4 × 10(-7), respectively; located in the CDKN2A/B gene region). CONCLUSIONS: We have identified a novel association between genetic variation in the CLPTM1L/TERT region and NPC. Supporting our finding, rs31489 and other SNPs in this region have been reported to be associated with multiple cancer sites, candidate-based studies have reported associations between polymorphisms in this region and NPC, the TERT gene has been shown to be important for telomere maintenance and has been reported to be overexpressed in NPC, and an EBV protein expressed in NPC (LMP1) has been reported to modulate TERT expression/telomerase activity. IMPACT: Our finding suggests that factors involved in telomere length maintenance are involved in NPC pathogenesis.

How genome-wide SNP-SNP interactions relate to nasopharyngeal carcinoma susceptibility.

This study is the first to use genome-wide association study (GWAS) data to evaluate the multidimensional genetic architecture underlying nasopharyngeal cancer. Since analysis of data from GWAS confirms a close and consistent association between elevated risk for nasopharyngeal carcinoma (NPC) and major histocompatibility complex class 1 genes, our goal here was to explore lesser effects of gene-gene interactions. We conducted an exhaustive genome-wide analysis of GWAS data of NPC, revealing two-locus interactions occurring between single nucleotide polymorphisms (SNPs), and identified a number of suggestive interaction loci which were missed by traditional GWAS analyses. Although none of the interaction pairs we identified passed the genome-wide Bonferroni-adjusted threshold for significance, using independent GWAS data from the same population (Stage 2), we selected 66 SNP pairs in 39 clusters with P<0.01. We identified that in several chromosome regions, multiple suggestive interactions group to form a block-like signal, effectively reducing the rate of false discovery. The strongest cluster of interactions involved the CREB5 gene and a SNP rs1607979 on chromosome 17q22 (P = 9.86×10(-11)) which also show trans-expression quantitative loci (eQTL) association in Chinese population. We then detected a complicated cis-interaction pattern around the NPC-associated HLA-B locus, which is immediately adjacent to copy-number variations implicated in male susceptibility for NPC. While it remains to be seen exactly how and to what degree SNP-SNP interactions such as these affect susceptibility for nasopharyngeal cancer, future research on these questions holds great promise for increasing our understanding of this disease's genetic etiology, and possibly also that of other gene-related cancers.

The relationship between secretory leukocyte protease inhibitor expression and Epstein-Barr virus status among patients with nasopharyngeal carcinoma.

AIM: The aim was to study the expression of Secretory Leukocyte Protease Inhibitor (SLPI) and to explore its correlation with the presence of Epstein-Barr Virus (EBV) among patients with nasopharyngeal carcinoma. MATERIALS AND METHODS: The expression levels of SLPI mRNA in NPC cell lines and in ten matched-pairs of NPC and adjacent normal tissue were examined by quantitative real-time Polymerase Chain Reaction (PCR). Furthermore, protein expression of SLPI in 71 paraffin-embedded NPC biopsies was assessed by immunohistochemistry. Finally, the serum level of SLPI in 177 NPC patients and 103 healthy controls was evaluated by enzyme-linked immunosorbent assay (ELISA). RESULTS: The expression of SLPI mRNA in NPC cells was significantly lower than in the adjacent normal epithelium (p<0.001). When the expression of SLPI in EBV-positive and -negative NPC cell lines was compared, we found that both mRNA and protein expressions of SLPI were significantly higher in EBV-negative cells. Furthermore, the results of immunohistochemical analysis demonstrated that the frequency of reduced SLPI expression in EBV-positive biopsies was significantly higher than that in EBV-negative biopsies. CONCLUSION: In this study, we have confirmed that SLPI is significantly down-regulated in NPC tissues. In addition, based on our preliminary results, we propose that the reduction of SLPI in NPC cells is associated with the presence of the EBV genome and/or the expression of EBV-encoded genes. SLPI may play an important role in EBV-mediated NPC tumorigenesis.

Evaluation of human leukocyte antigen-A (HLA-A), other non-HLA markers on chromosome 6p21 and risk of nasopharyngeal carcinoma.

BACKGROUND: The association between human leukocyte antigen (HLA) genes (located in the Major Histocompatibility Complex [MHC] region of chromosome 6p21) and NPC has been known for some time. Recently, two genome-wide association studies (GWAS) conducted in Taiwan and China confirmed that the strongest evidence for NPC association was mapped to the MHC region. It is still unclear, however, whether these findings reflect direct associations with Human Leukocyte Antigen (HLA) genes and/or to other genes in this gene-rich region. METHODS: To better understand genetic associations for NPC within the MHC region of chromosome 6, we conducted an evaluation that pooled two previously conducted NPC case-control studies in Taiwan (N = 591 cases and N = 521 controls). PCR-based genotyping was performed for 12 significant SNPs identified within 6p21 in the Taiwan NPC GWAS and for the HLA-A gene (exons 2 and 3). FINDINGS: After confirming homogeneity between the two studies, pooled odds ratios (OR) and 95% confidence intervals (CI) were estimated by logistic regression. We found that HLA-A (p-trend = 0.0006) and rs29232 (within the GABBR1 gene; p-trend = 0.005) were independent risk factors for NPC after adjustment for age, gender, study and each other. NPC risk was highest among individuals who were homozygous for the HLA-A*0207 risk allele and carriers of the rs29232 risk allele (A). CONCLUSION: Our study suggests that most of the SNPs significantly associated with NPC from GWAS reflect previously identified HLA-A associations. An independent effect of rs29232 (GABBR1), however, remained, suggesting that additional genes within this region might be associated with NPC risk.

The Epstein-Barr virus oncogene product, latent membrane protein 1, induces the downregulation of E-cadherin gene expression via activation of DNA methyltransferases.

The latent membrane protein (LMP1) of Epstein-Barr virus (EBV) is expressed in EBV-associated nasopharyngeal carcinoma, which is notoriously metastatic. Although it is established that LMP1 represses E-cadherin expression and enhances the invasive ability of carcinoma cells, the mechanism underlying this repression remains to be elucidated. In this study, we demonstrate that LMP1 induces the expression and activity of the DNA methyltransferases 1, 3a, and 3b, using real-time reverse transcription-PCR and enzyme activity assay. This results in hypermethylation of the E-cadherin promoter and down-regulation of E-cadherin gene expression, as revealed by methylation-specific PCR, real-time reverse transcription-PCR and Western blotting data. The DNA methyltransferase inhibitor, 5'-Aza-2'dC, restores E-cadherin promoter activity and protein expression in LMP1-expressing cells, which in turn blocks cell migration ability, as demonstrated by the Transwell cell migration assay. Our findings suggest that LMP1 down-regulates E-cadherin gene expression and induces cell migration activity by using cellular DNA methylation machinery.