Genetic risk factors for ovarian cancer and their role for endometriosis risk

Glypican3 and serglycin as potential biomarkers involved in the pathogenesis of ovarian endometriosis

Endometriosis, a non-malignant gynecological disorder characterized by debilitating symptoms, displays several cancer-like characteristics, including metastatic behavior and extracellular matrix (ECM) remodeling. The dynamics of ECM are largely influenced by proteoglycans (PGs), a family of glycosaminoglycan (GAG)-decorated proteins known for their regulatory impact on cellular behavior through ECM modulation. This study aimed to investigate the dysregulated expression of 20 PG genes in ovarian endometrioma (n = 24) in comparison to eutopic endometrial tissue samples (n = 16) from patients diagnosed with ovarian endometriosis, employing quantitative real-time PCR (qPCR) and immunohistochemistry (IHC). qPCR screening identified four upregulated PG genes-glypican 3 (GPC3), decorin (DCN), serglycin (SRGN), and glypican 5 (GPC5)-whereas 16 PG genes were found to be downregulated. In ovarian endometrioma, relative to eutopic endometrial tissue, GPC3 and SRGN expression were further verified to be significantly overexpressed by 18.6-fold (P < 0.05) and 6.7-fold (P < 0.01), respectively, whereas brevican (BCAN) and syndecan 4 (SDC4) were markedly downregulated by approximately 90 % and 86 %, respectively (both P < 0.001). IHC staining further validated the significant overexpression of GPC3 protein in ovarian endometrioma compared to eutopic and control endometrial tissues (P < 0.0001). In-silico analysis using the Enrichr database identified enriched functional pathways associated with the top overexpressed genes, such as hypoxia, glycolysis, and WNT signaling, known to be implicated in endometriosis. These findings suggest that the overexpression of GPC3 and SRGN may contribute to the pathogenesis of ovarian endometrioma, highlighting their potential as biomarkers and therapeutic targets for this disease.

Clinicopathological characteristics, molecular features and novel diagnostic strategies for the detection of malignant transformation of endometriosis (Review)

Endometriosis is a benign gynecological disease that affects women of reproductive age. Although malignant transformation of endometriosis is rare, physicians must be aware of this due to the high incidence of clear cell carcinoma of the ovary (CCC) in Japan. The most prevalent histological subtype of ovarian cancer is CCC (~70%) followed by endometrioid carcinoma (30%). The present review discusses the clinicopathological and molecular features of endometriosis-associated ovarian cancer (EAOC) as well as prospects for novel diagnostic strategies. Papers published between 2000 and 2022 in the PubMed and Google Scholar databases were included. Contents of the endometriotic cyst fluid may be involved in carcinogenesis, although the underlying mechanisms are largely unknown. Some studies have proposed a possible mechanism wherein excessive hemoglobin, heme and iron could cause an imbalance in intracellular redox homeostasis in endometriotic cells. Combined with DNA damage and mutations, the imbalances may induce the development of EAOC. Endometriotic cells evolve to adapt to the prolonged unfavorable oxidative microenvironmental stress. On the other hand, macrophages enhance the antioxidative defense mechanism and protect endometriotic cells against oxidative damage through intercellular crosstalk and signaling pathways. Therefore, changes in redox signaling, energy metabolism and the tumor immune microenvironment could be the key elements in the malignant transformation of certain endometriotic cell clones. Additionally, non-invasive bioimaging (i.e., magnetic resonance relaxometry) and biomarkers (i.e., tissue factor pathway inhibitor 2) may be promising tools for early-stage detection of the disease. In conclusion, the present review summarizes the latest advancements in research on the biological characteristics and early diagnosis of malignant transformation of endometriosis.

Endometriosis-Associated Ovarian Cancer: What Are the Implications for Women with Intact Endometrioma Planning for a Future Pregnancy? A Reproductive Clinical Outlook

Endometriosis is a chronic, universal, and prevalent disease estimated to affect up to 1:10 women of reproductive age. Endometriosis-associated ovarian cancer (EAOC) developing at reproductive age is challenging and of concern for women and practitioners alike. This outlook review focuses on the occurrence of EAOC, especially in infertile women or those planning for a future pregnancy, from the perspective of a reproductive endocrinologist, based on recent evidence. Contemporary pathogenesis, genetic profiles, evidence of causality, clinical diagnosis, prognosis, and up-to-date management are discussed. EAOC seems to be merely associated with endometrioma and includes clear-cell and endometrioid ovarian carcinoma. Although endometrioma is frequently found in women of reproductive age (up to 1:18 of women), EAOC appears to be a rare occurrence. These women are of more advanced reproductive age, nulliparous, and hyperestrogenic, with a large-sized unilateral endometrioma (>9 cm) containing solid components and papillary projections. Each case suspected to have EAOC has specific characteristics, and a multidisciplinary discussion and appropriate patient counseling should be conducted to reach an optimal therapeutic plan. Since most of these cases are diagnosed at an early stage with a favorable prognosis, fertility-sparing surgery may be feasible. The pros and cons of fertility preservation techniques should be discussed.

Molecular, cellular and systemic aspects of epithelial ovarian cancer and its tumor microenvironment

Ovarian cancer encompasses a heterogeneous group of malignancies that involve the ovaries, fallopian tubes and the peritoneal cavity. Despite major advances made within the field of cancer, the majority of patients with ovarian cancer are still being diagnosed at an advanced stage of the disease due to lack of effective screening tools. The overall survival of these patients has, therefore, not substantially improved over the past decades. Most patients undergo debulking surgery and treatment with chemotherapy, but often micrometastases remain and acquire resistance to the therapy, eventually leading to disease recurrence. Here, we summarize the current knowledge in epithelial ovarian cancer development and metastatic progression. For the most common subtypes, we focus further on the properties and functions of the immunosuppressive tumor microenvironment, including the extracellular matrix. Current and future treatment modalities are discussed and finally we provide an overview of the different experimental models used to develop novel therapies.

Coexistence of cervical endometriosis with premalignant and malignant gynecological pathologies: report on a series of 27 cases

Although cervical endometriosis represents a rare condition, there is evidence that implicates a complex interaction with other gynecological pathologies. This study aims to highlight this entity and further to explore the impact of oncological pathology of female genital tract on patients with cervical endometriosis. We retrospectively investigated the medical and pathological reports of 27 cases with cervical endometriosis, which were diagnosed by tissue biopsy. The results of the study show a relationship between CIN (cervical intraepithelial neoplasia) cases 19/27 (70percent) and cervical endometriosis. CIN I was more frequently found compared to patients with CIN II and CIN III. Furthermore, a high prevalence of HPV (human papilloma virus) was confirmed. Out of 27 patients, 2 cases with cervical (7.4percent), 2 with endometrial (7.4percent) and 3 with ovarian cancer (11.1percent) were detected. We confirmed the coexistence of more than one malignant gynecological pathology with cervical endometriosis in four cases (14.8percent). To conclude, cervical endometriosis is a rare disease co-existing considerably with premalignant and malignant gynecological conditions according to our data. Although the pathophysiology and genetics of cervical dysplasia is well delineated, further research is needed to establish the association between cervical endometriosis and gynecological premalignant and malignant pathology.

The relation between endometrioma and ovarian cancer

INTRODUCTION

The relationship between endometrioma and ovarian cancer is a topic of discussion in the field of endometriosis and to date it is still debated whether ovarian endometriosis may represent a risk factor for ovarian cancers.

EVIDENCE ACQUISITION

A literature search was carried out using Cochrane Library, EMBASE, Medline and Google Scholar up to October 2020. Primary outcome of interest was ovarian cancer incidence in patients with endometriosis. Secondary outcome was ovarian cancer prognosis in patients with endometriosis compared to patient without endometriosis.

EVIDENCE SYNTHESIS

Patients with ovarian endometriosis has a slight increase risk of developing ovarian cancer (merely 1.8%), being the general population risk for ovarian cancer 1.31%. In patient at postmenopausal age, long-lasting endometriosis, early-age diagnosis, infertility and/or infertility treatment the risk of developing ovarian cancer is higher. Endometriosis-related ovarian cancers are generally clear cell and endometrioid and are diagnosed at early stage compared to non-endometriosis related ovarian cancer.

CONCLUSIONS

The lifetime risk for ovarian cancer is low in endometriosis patients in general and higher in subgroups of patients allowing a tailored management based on patient characteristics. Endometriosis is a chronic disease negatively affecting the quality of life, nonetheless, concerns on ovarian cancer should be avoided in order to reduce the burden of the disease on women's health.

Acquired Evolution of Mitochondrial Metabolism Regulated by HNF1B in Ovarian Clear Cell Carcinoma

Clear cell carcinoma (CCC) of the ovary exhibits a unique morphology and clinically malignant behavior. The eosinophilic cytoplasm includes abundant glycogen. Although the growth is slow, the prognosis is poor owing to resistance to conventional chemotherapies. CCC often arises in endometriotic cysts and is accompanied by endometriosis. Based on these characteristics, three clinical questions are considered: why does ovarian cancer, especially CCC and endometrioid carcinoma, frequently occur in endometriotic cysts, why do distinct histological subtypes (CCC and endometrioid carcinoma) arise in the endometriotic cyst, and why does ovarian CCC possess unique characteristics? Mutations in AT-rich interacting domain-containing protein 1A and phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit alpha genes may contribute to the carcinogenesis of ovarian CCC, whereas hepatocyte nuclear factor-1-beta (HNF1B) plays crucial roles in sculpting the unique characteristics of ovarian CCC through metabolic alterations. HNF1B increases glutathione synthesis, activates anaerobic glycolysis called the Warburg effect, and suppresses mitochondria. These metabolic changes may be induced in stressful environments. Life has evolved to utilize and control energy; eukaryotes require mitochondria to transform oxygen reduction into useful energy. Because mitochondrial function is suppressed in ovarian CCC, these cancer cells probably acquired further metabolic evolution during the carcinogenic process in order to survive stressful environments.

LncRNA CTBP1-AS2 regulates miR-216a/ PTEN to suppress ovarian cancer cell proliferation

Background

We analyzed TCGA dataset and observed the downregulation of CTBP1-AS2 in ovarian cancer (OC), while the function of CTBP1-AS2 has only been investigated in diabetes and cardiomyocyte hypertrophy, but not in cancer biology. We therefore analyzed the involvement of CTBP1-AS2 in OC.

Result

We found that CTBP1-AS2 was downregulated in OC and predicted poor survival. CTBP1-AS2 in luciferase activity assay interacted with miR-216a, while overexpression of CTBP1-AS2 and miR-216a had no significant effects on the expression of each other. However, increased expression level of PTEN, a target of miR-216a, was observed after CTBP1-AS2 overexpression. Increased proliferation rate of OC cells was observed after the overexpression of miR-216a. CTBP1-AS2 and PTEN overexpression resulted in the reduced proliferation rate of OC cells and reduced effects of miR-216a overexpression.

Conclusion

CTBP1-AS2 regulates miR-216a/PTEN to suppress OC cell proliferation.

Identification of a FAS/FASL haplotype associated with endometriosis in Iranian patients

Risk factors for ovarian cancer include a number of genetic variants as well as endometriosis. The FAS-FASL system is one of the apoptotic pathways that play an essential role in the apoptotic process within the endometrium. Here, we evaluate the correlation between FAS-FASL polymorphisms with the risk of endometriosis in Iranian patients and healthy controls. We extracted DNA from whole blood samples using a DNA Purification Kit. Using the PCR-RFLP method, three SNPs, including FAS (-670 A/G) and FASL (-844 C/T and _124G/A) genes, were genotyped in 112 patients with endometriosis as well as 110 healthy controls. The frequency of genotypes and the alleles of these SNPs were analyzed by the chi-squared test for the significant association. Haplotype analysis was done by the PLINK software. The frequency distribution of haplotypes was significant between SNPs so that the ACG haplotype was more frequent in the cases than in the controls (p = .017). These results indicate that haplotype analysis can be useful for SNP analysis. The ACG haplotypes in FAS-670A/G, FASL-844C/T, and _124G/A genes may be correlated with the progression of endometriosis.

Association between endometriosis and gynecological cancers: a critical review of the literature

BACKGROUND

Endometriosis is one of the most common benign gynecological diseases with an occurrence approximately 10% in reproductive age. Endometriosis has been proposed as a possible precursor of certain ovarian carcinomas such as clear cell and endometrioid ovarian carcinomas. In addition to this pathogenic link, the association with other gynecological tumors and breast cancer has been studied on an epidemiological basis in several studies.

OBJECTIVE

The aim of this review was to critically present the recent published evidence on the association of endometriosis with gynecological cancer, and with a special emphasis on ovarian cancer.

MATERIALS AND METHODS

A search for eligible studies was conducted in three electronic databases, MEDLINE, EMBASE and CINAHL, for original research in humans published in any language.

RESULTS

The present review includes studies examining the association between endometriosis and different types of gynecological cancer (i.e., 25 studies on ovarian cancer, 8 studies on breast cancer, 8 studies on endometrial cancer and 2 studies on cervical cancer).

CONCLUSION

The present literature supports the pre-existing evidence suggesting an association between ovarian cancer and endometriosis and specifically its two histologic subtypes (endometrioid and ovarian clear cell cancer). The most recent population-based epidemiological studies cannot provide a clear association between endometriosis and endometrial, cervical or breast cancer.

TERT rs10069690 polymorphism and cancers risk: A meta-analysis

BACKGROUND

Studies have identified that the telomerase reverse transcriptase (TERT) gene polymorphism rs10069690 (C>T) is associated with cancer risk, but the results remain inconclusive.

METHODS

To provide a more precise estimation of the relationship, we performed a meta-analysis of 45 published studies including 329,035 cases and 730,940 controls. We conducted a search in PubMed, Google Scholar and Web of Science to select studies on the association between rs10069690 and cancer risk. Stratification by ethnicity, cancer type, cancers' classification, source of control, sample size, and genotype method was used to explore the source of heterogeneity. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were evaluated using random effects models. Sensitivity, publication bias, false-positive report probability (FPRP) and statistical power were also assessed.

RESULTS

The result demonstrated that rs10069690 was significantly associated with an increased risk of cancer overall (OR = 1.09, 95% CI: 1.06-1.12, p < .001) under the allele model. Stratification analysis revealed an increased cancer risk in subgroups of breast cancer, ovarian cancer, lung cancer, thyroid cancer, and renal cell carcinoma (RCC). However, a significantly decreased association was observed in pancreatic cancer in the European population (OR = 0.93,95% CI: 0.87-0.99, p = .031). In the subgroup analysis based on cancer type, no significant association was found in prostate cancer, leukemia, colorectal cancer and glioma.

CONCLUSIONS

This meta-analysis suggested that the TERT rs10069690 polymorphism may be a risk factor for cancer, especially breast cancer, ovarian cancer, lung cancer, thyroid cancer, and RCC. Further functional studies are warranted to reveal the role of the polymorphism in carcinogenesis.

Cumulative evidence for relationships between multiple variants of HNF1B and the risk of prostate and endometrial cancers

Background

To provide a synopsis of the current understanding of the association between variants of HNF1B and cancer susceptibility, we conducted a comprehensive research synopsis and meta-analysis to evaluate associations between HNF1B variants and prostate and endometrial cancers.

Results

Eighteen studies totaling 34,937 patients and 55,969 controls were eligible for this meta-analysis. Four variants showed a significant association with the risk of individual cancer. Strong significant associations were found between rs4430796 A and the risk of both prostate cancer (OR = 1.247, p = 2.21 × 10^− 77) and endometrial cancer (OR = 1.217, p = 8.98 × 10^− 16); the AA, AG genotypes also showed strong significant associations with the risk of prostate cancer (OR1 = 1.517, p = 4.46 × 10^− 22; OR2 = 1.180, p = 0.002). There was a strong significant association between rs7501939 G and the risk of prostate cancer (OR = 1.201, p = 9.31 × 10^− 31). Strong significant association was found between rs11649743 G (OR = 1.138, p = 1.08 × 10^− 12), rs3760511 C (OR = 1.214, p = 1.57 × 10^− 19) and the prostate cancer risk;the GG, AG genotypes of rs11649743 also showed strong significant associations with the risk of prostate cancer (OR1 = 1.496, p = 3.32 × 10^− 6; OR2 = 1.276, p = 7.82 × 10^− 6). All the cumulative epidemiological evidence of associations was graded as strong.

Conclusions

Our study summarizes the evidence and helps to reveal that common variants of HNF1B are associated with risk of prostate and endometrial cancer.

Novel CTCF mutations in Chinese patients with ovarian endometriosis

Endometriosis is a common gynecological disease characterized by the outgrowth of the endometrium, however, the detailed molecular etiology remains largely uncharacterized. Recent studies have implicated that endometriosis is potentially a precancerous lesion, and that CCCTC‑binding factor (CTCF) mutations may be involved in the pathogenesis of this disorder. However, the detailed CTCF mutation spectrum in Chinese patients with ovarian endometriosis remains largely unknown. In the present study, a cohort of 92 patients with ovarian endometriosis were analyzed for the presence of CTCF mutations by sequencing the entire coding regions. In addition, 67 healthy eutopic endometrial tissues and 46 healthy ovarian tissues from control samples (without endometriosis) were also analyzed. In total, two CTCF missense mutations, p.K206E (c.616A>G) and p.H373L (c.1118A>T), were identified in 2/92 (2.2%) endometriotic lesions. The patient with the p.K206E mutation was 26 years old and diagnosed with primary infertility, whereas the patient with the p.H373L mutation was 37 years old and concurrently diagnosed with uterine leiomyoma. The p.H373L mutation was previously identified in endometrial cancer samples with low frequency, while the p.K206E mutation was novel. In addition, no CTCF mutations were detected in the 67 healthy eutopic endometrial and 46 healthy ovarian tissue samples. In silico prediction and evolutionary conservation analysis suggested that these CTCF mutations may be pathogenic. In summary, the present study identified 2 potential pathogenic CTCF mutations in endometriotic lesions from 2/92 patients with ovarian endometriosis. These results, together with a prior exome‑sequencing based study, suggest that CTCF mutations may be involved in the development of ovarian endometriosis.

Association between ovarian cancer and advanced endometriosis

We retrospectively analyzed clinicopathological data in two different countries over the past years on the association between ovarian endometriosis and ovarian carcinoma. Medical and pathological reports were evaluated from 1,000 patients with endometriosis from two different geographical areas. The prevalence and women characteristics of cases were analyzed. Endometriosis-associated ovarian cancer was present in 20 (2%) cases, among the study subjects. The observed prevalence was 12 (60%) for endometrioid carcinoma, 4 (20%) for clear cell ovarian carcinoma, 2 (10%) for serous and 2 (10%) for mucinous adenocarcinoma. A higher proportion of endometrioid carcinoma cases were noted in comparison with other types (P<0.001). We found only 3/20 (15%) postmenopausal cases. In all cases, we reported advanced stage of endometriosis (stage III or IV). Left-sided endometrioid carcinoma were notably more common than right-sided ones (P<0.001). In the majority of cases, malignant transformation of endometriosis was observed in endometrioid carcinoma or clear cell carcinoma of the ovary. Further research is required to establish the relationship between endometriosis and ovarian cancer.

Novel TRERF1 mutations in Chinese patients with ovarian endometriosis

Endometriosis is an estrogen-dependent precancerous lesion exhibiting frequently perturbed level of steroid hormones and transcriptional‑regulating factor 1 (TRERF1) has a crucial role in the production of steroid hormones including estrogen. Endometriosis has previously been revealed to be a precancerous lesion that harbors somatic mutations in cancer‑associated genes. Therefore, the authors of the present study hypothesize that TRERF1 aberrations may be involved in the development of endometriosis. In the present study, endometriotic lesions and paired blood samples from 92 individuals with ovarian endometriosis were analyzed for the potential presence of TRERF1 mutations by sequencing the entire coding region and the corresponding intron‑exon boundaries of the TRERF1 gene. Two heterozygous missense somatic mutations [c.3166A>C (p.K1056Q) and c.3187 G>A (p.G1063R)] in the TRERF1 gene were identified in two out of 92 ectopic endometria (2.2%), to the best of our knowledge, these mutations have not been previously reported. From the two samples with TRERF1 mutations, one sample was from a 42‑year‑old patient also diagnosed with uterine leiomyoma and the other mutation was identified in a 36‑year‑old woman exhibiting no other apparent gynecological conditions. The evolutionary conservation analysis and in silico prediction of these TRERF1 mutations suggested that they may be pathogenic. To the best of our knowledge, the present study was the first to identify 2 novel, potentially 'disease‑causing' TRERF1 somatic mutations in the endometriotic lesions in 2 out of 92 patients with ovarian endometriosis; therefore, TRERF1 mutations may be involved in the pathogenesis of ovarian endometriosis.

10H-3,6-Diazaphenothiazine induces G2/M phase cell cycle arrest and caspase-dependent apoptosis and inhibits cell invasion of A2780 ovarian carcinoma cells through the regulation of NF-κB and (BIRC6-XIAP) complexes

The asymptomatic properties and high treatment resistance of ovarian cancer result in poor treatment outcomes and high mortality rates. Although the fundamental chemotherapy provides promising anticancer activities, it is associated with severe side effects. The derivative of phenothiazine, namely, 10H-3,6-diazaphenothiazine (PTZ), was synthesized and reported with ideal anticancer effects in a previous paper. In this study, detailed anticancer properties of PTZ was examined on A2780 ovarian cancer cells by investigating the cytotoxicity profiles, mechanism of apoptosis, and cell invasion. Research outcomes revealed PTZ-induced dose-dependent inhibition on A2780 cancer cells (IC₅₀ =0.62 µM), with significant less cytotoxicity toward HEK293 normal kidney cells and H9C2 normal heart cells. Generation of reactive oxygen species (ROS) and polarization of mitochondrial membrane potential (ΔΨm) suggests PTZ-induced cell death through oxidative damage. The RT² Profiler PCR Array on apoptosis pathway demonstrated PTZ-induced apoptosis via intrinsic (mitochondria-dependent) and extrinsic (cell death receptor-dependent) pathway. Inhibition of NF-κB and subsequent inhibition of (BIRC6-XIAP) complex activities reduced the invasion rate of A2780 cancer cells penetrating through the Matrigel™ Invasion Chamber. Lastly, the cell cycle analysis hypothesizes that the compound is cytostatic and significantly arrests cell proliferation at G₂/M phase. Hence, the exploration of the underlying anticancer mechanism of PTZ suggested its usage as promising chemotherapeutic agent.

Marital status and survival in epithelial ovarian cancer patients: a SEER-based study

Marital status has been proved to be correlated to the survival of patients in various cancer types, except for that in the large female population of epithelial ovarian cancer (EOC). In this study, we retrospectively extracted 10905 eligible EOC patients from the Surveillance, Epidemiology, and End Results (SEER) database in the period from 2004 to 2012. We categorized marital status as married, divorced/separated, widowed, and never married. Chi-square test was used to investigate the association between marital status and other variables. The Kaplan-Meier test was adopted to compare survival curves of different groups. Multivariate Cox regression analyses were conducted to estimate the effect of marital status on overall survival (OS) and epithelial ovarian cancer-specific survival (EOCSS). To explore how marital status affected patients diagnosed at the same stage, we further performed subgroup analyses according to TNM stage. The results showed that marital status was an independent predictor for OS and EOCSS. Subgroup analyses indicated that the relationship between marital status and prognosis varied according to different conditions. Widowed patients had poorer prognosis than the other groups in most conditions, while the never married group showed similar risk of mortality as the married ones.

Summary of Future Developments

Endometriosis is a chronic disease with the potential to cause devastating clinical manifestations such as infertility and chronic pelvic disease. Current treatment is limited to surgical intervention and pharmacologic therapy targeting estrogen and progesterone to suppress ectopic endometrial tissue proliferation. Undesired side effects and contraindications to the use of hormonal medications may reduce treatment options. As the pathogenesis of endometriosis continues to be investigated, new therapies will emerge. The identification of genes involved in the development of endometriosis may allow targeted therapy to prevent or cure disease. In addition, increasing knowledge of the inflammatory pathways that promote ectopic endometrial growth will permit the development of pharmacologic agents to manipulate these signaling pathways. Utilization of selective progesterone receptor modulators, aromatase inhibitors, and modern gonadotropin-releasing hormone antagonists provide more options to manage disease when traditional treatment fails. Individualized therapeutic strategies will soon be a reality as a greater understanding of endometriosis is obtained through the investigation of genomic studies, molecular pathways, and environmental influences.

Identification of four prognostic LncRNAs for survival prediction of patients with hepatocellular carcinoma

Background

As the fifth most common cancer worldwide, Hepatocellular carcinoma (HCC) is also the third most common cause of cancer-related death in China. Several lncRNAs have been demonstrated to be associated with occurrence and prognosis of HCC. However, identification of prognostic lncRNA signature for HCC with expression profiling data has not been conducted yet.

Methods

With the reuse of public available TCGA data, expression profiles of lncRNA for 371 patients with HCC were obtained and analyzed to find the independent prognostic lncRNA. Based on the expression of lncRNA, we developed a risk score model, which was evaluated by survival analysis and ROC (receiver operating characteristic) curve. Enrichment analysis was performed to predict the possible role of the identified lncRNA in HCC prognosis.

Results

Four lncRNAs (RP11-322E11.5, RP11-150O12.3, AC093609.1, CTC-297N7.9) were found to be significantly and independently associated with survival of HCC patients. We used these four lncRNAs to construct a risk score model, which exhibited a strong ability to distinguish patients with significantly different prognosis (HR = 2.718, 95% CI [2.103–3.514], p = 2.32e−14). Similar results were observed in the subsequent stratification survival analysis for HBV infection status and pathological stage. The ROC curve also implied our risk score as a good indicator for 5-year survival prediction. Furthermore, enrichment analysis revealed that the four signature lncRNAs may be involved in multiple pathways related to tumorigenesis and prognosis.

Discussion

Our study recognized four lncRNAs to be significantly associated with prognosis of liver cancer, and could provide novel insights into the potential mechanisms of HCC progression. Additionally, CTC-297N7.9 may influence the downstream TMEM220 gene expression through cis-regualtion. Nevertheless, further well-designed experimental studies are needed to validate our findings.