A novel genome-based approach correlates TMPRSS3 overexpression in ovarian cancer with DNA hypomethylation

Objective

In an attempt to analyze more profoundly aberrant DNA hypomethylation in epithelial ovarian cancer (EOC), we applied a novel genome-based approach which includes expression profiling following pharmacologic stimulation of DNA methylation with the methyl donor S-adenosyl-l-methionine (SAM).

Methods

Four different EOC cell lines (OVCAR3, SKOV3, TOV21 and TOV112) were treated with SAM, and gene expression profiling was performed in SAM-treated and control EOC cells. Genes, downregulated upon SAM treatment were considered as potentially hypomethylated in EOC. DNA hypomethylation was independently validated in ovarian tumor and control tissues by bisulfite sequencing PCR (BSP).

Results

Among the genes identified, one of particular interest was the type II serine protease TMPRSS3 gene variants A and D (TMPRSS3-A/D), previously recognized as overexpressed in EOC and representing potential EOC therapeutic targets. Consecutive BSP analysis demonstrated that the common putative promoter region of the TMPRSS3-A/D gene variants was significantly hypomethylated in high-grade serous EOC tumors, compared to low-malignant potential ovarian tumors and normal ovarian tissue.

Conclusions

Our data imply that TMPRSS3-A/D overexpression in EOC is probably due to hypomethylation of their control region thus indicating that TMPRSS3-A/D variants could also represent novel molecular targets for epigenetic therapy of late stages of the disease. Our results also suggest that the frequently observed upregulation of different members of the type II serine proteases gene family in advanced cancer could be due to aberrant DNA hypomethylation. Furthermore, our study introduces a promising discovery approach that could be used for the identification of hypomethylated genes in different experimental cell models.     

No benefit from combining HE4 and CA125 as ovarian tumor markers in a clinical setting

Objective

About 70% of epithelial ovarian cancer patients (EOC) are diagnosed at advanced stage with a five-year survival rate of only 30%. Whilst CA125 detects peritoneally-spread disease, it has limited sensitivity for early cancers, many of which are potentially curable.

Methods

We compared the new commercially available tumor marker HE4 with CA125 individually, in combination, within the risk of malignancy index (RMI) and the newly defined risk of malignancy algorithm (ROMA). Our prospectively-collected cohort of 160 patients consisted of healthy controls, benign diseases, and borderline tumors/adenocarcinomas of ovarian, tubal, peritoneal and endometrial origin. HE4 and CA125 were measured in serum using standardized ELISA.

Results

Both markers showed similar diagnostic performance in the detection of EOC at clinically defined thresholds (CA125 35 U/ml; HE4 70 pM) but HE4 was not elevated in endometriosis. Comparison of non-malignant diagnoses (n = 71) versus early stage ovarian and tubal cancers (n = 19) revealed that HE4 and ROMA displayed the best diagnostic performance (AUC 0.86/0.87, specificity 85.9%/87.3% and sensitivity 78.9%/78.9%, respectively). Whilst RMICA125 detects peritoneal cancer better than all other models (AUC 0.99, specificity 97.2%, sensitivity 80.0%), there is no other detection benefit from RMI compared to HE4 alone or included in ROMA.

Conclusions

The major advantage of HE4 lies in its specificity and improved detection of borderline tumors and early stage ovarian and tubal cancers. HE4 is superior to CA125 with or without RMI and ROMA indices. However, we see no benefit from combining both markers in clinical practice.     

Hypermethylated DAPK in serum DNA of women with uterine leiomyoma is a biomarker not restricted to cancer

Objective

Ovarian cancer is most frequently diagnosed at a late stage with a poor prognosis. No markers for early diagnosis have been established. Aberrantly methylated DNA appears as a promising molecular cancer marker. The aim of this study was to analyze the methylation status of the proapoptotic cancer related gene death-associated protein kinase (DAPK) in ovarian cancer patients, healthy controls and in patients suffering from a benign proliferative disease such as uterine leiomyoma.

Methods

Methylation-specific PCR (MSP) was used to detect DAPK methylation in primary tumor tissue and serum of both ovarian cancer (n = 32) and uterine leiomyoma patients (n = 17 primary tissue, n = 30 serum). Serum samples from healthy women served as controls (n = 20). MSP results were confirmed by restriction digest and sequencing analyses of cloned PCR products.

Results

DAPK methylation was detected in 50% and 35.3% of primary tissue and 56% and 23.8% of serum samples from ovarian cancer and leiomyoma patients, respectively. However, the association of methylation frequencies in tissue and serum was low (kappa = −0.053). Sequencing experiments revealed fully methylated MSP products in sera of both ovarian cancer and leiomyoma patients. In contrast sera from control patients showed only partially methylated DAPK sequences.

Conclusion

DAPK hypermethylation was neither specific for the tissue of origin nor for cancer. The high prevalence of leiomyoma compromises the utility of this gene as a serum marker for early ovarian cancer detection. These data emphasize the necessity to co-analyze controls presenting with non-cancer proliferative disease in the quest for molecular cancer markers.     

There is no decision to make: experiences and attitudes toward treatment-focused genetic testing among women diagnosed with ovarian cancer

Objective

There is growing evidence that the BRCA mutation status of women newly diagnosed with ovarian cancer may be used to make treatment recommendations in the future. This qualitative study aimed to assess women's attitudes and experiences toward treatment-focused genetic testing (TFGT).

Methods

Women (N = 22) with ovarian cancer who had either (i) advanced disease and had previously had TFGT (n = 12) or (ii) had a recent ovarian cancer diagnosis and were asked about their hypothetical views of TFGT (n = 10), were interviewed in-depth.

Results

This study demonstrates that patients diagnosed with ovarian cancer found the concept of TFGT acceptable with the primary motivation for genetic testing being to increase their treatment options. Women reported that there was no decision to make about TFGT, and the advantages of TFGT were perceived to outweigh the disadvantages. Many women described elements of resilience and active coping, in the context of hypothetical and actual TFGT.

Conclusions

Resilience and active coping strategies are important factors that warrant investigation as potential moderators of psychological distress in future prospective studies exploring the optimal way of offering BRCA genetic testing to women newly diagnosed with ovarian cancer, and to assess the impact of TFGT upon patients' survival, psychological distress, and quality of life.     

BRCA1/2 mutations and expression: response to platinum chemotherapy in patients with advanced stage epithelial ovarian cancer

Objective

Our objective was to determine the rate of BRCA1/2 deficiency in platinum-sensitive and platinum-resistant tumors from a cohort of unselect patients with advanced epithelial ovarian cancer (EOH).

Methods

BRCA1/2 mutation analysis was performed in 29 patients with platinum-sensitive EOC and 24 patients with platinum-resistant disease. Germline DNA was analyzed in mutation carriers when normal tissue was available. BRCA expression was ascertained by quantitative rt-PCR. Associations between BRCA mutation status and expression levels and parameters of platinum response were analyzed.

Results

Fifteen of 53 (28.3%) EOC tumors had BRCA1/2 mutations. Twelve mutations were in BRCA1, while 3 involved BRCA2. Of the 12 mutation-carriers with normal tissue available for DNA analyses, 33.3% of the mutations were found to be somatic. Three mutations were novel. The majority of BRCA mutations (73%) were identified in patients with platinum-sensitive disease. In total, 38% of platinum-sensitive tumors were found to have a BRCA mutation, compared to 17% of the platinum-resistant patients. A statistical trend toward platinum-sensitive disease was seen in BRCA mutation carriers (p = 0.079). Nineteen (36%) study patients had some form of BRCA deficiency, and these patients were less likely to have platinum-resistant tumors (OR = 0.29; p value = 0.048).

Conclusions

BRCA mutations occurred more frequently in platinum-sensitive EOC than platinum-resistant disease. The high overall frequency of BRCA deficiency in EOC underscores the importance of tumor profiling as therapies targeting the DNA repair pathway are being investigated.     

Incidence of and risk factors for postoperative ileus in women undergoing primary staging and debulking for epithelial ovarian carcinoma

Objective

Thorough primary cytoreduction for epithelial ovarian carcinoma (EOC) improves survival. The incidence of postoperative ileus (POI) in these patients may be underreported because of varying POI definitions and the evolving, increasingly complex contemporary surgical approach to EOC. We sought to determine the current incidence of POI and its risk factors in women undergoing debulking and staging for EOC.

Methods

We retrospectively identified the records of women who underwent primary staging and cytoreduction for EOC between 2003 and 2008. POI was defined as a surgeon's diagnosis of POI, return to nothing-by-mouth status, or reinsertion of a nasogastric tube. Perioperative patient characteristics and process-of-care variables were analyzed. Univariate analyses were used to identify POI risk factors; variables with P ≤ .20 were included in multivariate analysis.

Results

Among 587 women identified, the overall incidence of POI was 30.3% (25.9% without bowel resection, 38.5% with bowel resection; P = .002). Preoperative thrombocytosis, involvement of bowel mesentery with carcinoma, and perioperative red blood cell transfusion were independently associated with increased POI. Postoperative ibuprofen use was associated with decreased POI risk. Women with POI had a longer length of stay (median, 11 vs 6 days) and increased time to recovery of the upper (7.5 vs 4 days) and lower (4 vs 3 days) gastrointestinal tract (P < .001 for each).

Conclusions

The rate of POI is substantial among women undergoing staging and cytoreduction for EOC and is associated with increased length of stay. Modifiable risk factors may include transfusion and postoperative ibuprofen use. Alternative interventions to decrease POI are needed.     

Therapy-related myeloid leukemia after treatment for epithelial ovarian carcinoma: an epidemiological analysis

Objective

Therapy related acute myeloid leukemia (t-AML) is a potential late complication of cytotoxic therapy, and it is of particular concern in the treatment of patients with epithelial ovarian carcinoma (EOC) exposed to multiple courses of chemotherapy during the course of their disease. This study examines the incidence, characteristics and clinical outcomes of patients who developed secondary myeloid-type leukemia after a diagnosis of EOC.

Methods

National Cancer Institute's Surveillance, Epidemiology and End Results database was pooled for diagnosis of secondary myeloid leukemia after an initial diagnosis of EOC. This group of patients was compared to patients with de novo AML, and to EOC patients who did not develop secondary myeloid leukemia. Demographic, cytopathological and survival data were recorded. Cox Proportional Hazards model was used to calculate hazard ratios (HR) for developing secondary leukemia and to determine the statistically significant variables impacting survival. Kaplan-Meier estimates of survival were obtained and comparisons between the groups were performed using log-rank test.

Results

One hundred and nine myeloid leukemia cases were identified among 63,359 patients with a prior diagnosis of EOC for an overall incidence of 0.17%. The median latency to development of leukemia was 4 years (range 0-27 years). Median survival from the time of secondary leukemia diagnosis was 3 months and significantly worse than the 6 month median survival in patients with de novo AML (p < 0.001). Age at leukemia diagnosis greater than 65 and development of secondary vs. de novo leukemia had a statistically worse prognosis on multivariate analysis (HR of 2.69, 95%CI 2.60-2.78 and 1.81, 95%CI 1.49-2.20 respectively). The development of secondary leukemia was more common with EOC diagnosis made prior to the platinum/taxane era (HR 6.70, 95%CI 3.69-12.18). There was no difference in median survival between EOC patients who developed AML and those who did not.

Conclusion

Development of t-AML is a rare but lethal event among EOC patients, and its incidence has decreased significantly since the use of platinum/taxane-based chemotherapy became the standard of care.     

MMP-1-PAR1 axis mediates LPA-induced epithelial ovarian cancer (EOC) invasion

Objectives

MMP-1 is over-expressed in many cancers, with high expression often associated with poor survival. In the present study, we examined the expression of MMP-1 in EOC and its role in EOC invasion. Moreover, we evaluated the role of a newly identified MMP-1-protease activated receptor (PAR)-1 axis in LPA-induced EOC invasion.

Methods

MMP-1 and PAR1 mRNA expression in EOC cell lines was determined by real time PCR. MMP-1 mRNA expression in 96 normal and carcinoma ovarian tissue specimens was analyzed using a TissueScan real time PCR array. MMP-1 concentration in conditioned medium was measured by MMP-1 ELISA. PAR1 protein expression was detected by Western blotting. Cell invasion was evaluated by in vitro Matrigel invasion assay.

Results

In ovarian tumor tissues more MMP-1 expression was observed than in normal ovarian tissues (p < 0.05), and its expression correlated with tumor grade (grade 3 > grade 2 > grade 1). Human recombinant MMP-1 as well as serum free conditioned medium containing high levels of MMP-1 from DOV13 and R182 cells significantly promoted DOV13 cell invasion (p < 0.05), implicating a direct role of MMP-1 in EOC invasion. Moreover, MMP-1 induced DOV13 invasion was significantly blocked by PAR1 siRNA silencing. Furthermore, MMP-1 and PAR1 were both significantly induced by LPA (20 μM), and siRNA silencing of MMP-1 and PAR1 both significantly reduced LPA's invasion-promoting effect in DOV13 cells (p < 0.05).

Conclusions

Our results suggest that the MMP-1-PAR1 axis is involved in EOC invasion and at least partially mediates LPA-induced EOC invasion. Therefore, blocking MMP-1 or PAR1 may represent a new therapeutic option for metastatic EOC.     

Expression of 67-kDa laminin receptor was associated with tumor progression and poor prognosis in epithelial ovarian cancer

Objective

67-kDa laminin receptor (67LR) has been identified as a prognostic biomarker for a variety of human cancers. We investigated the clinical significance of 67LR expression and its functional role in epithelial ovarian cancer (EOC).

Methods

67LR expression was evaluated by immunohistochemistry in 62 patients with EOC. We assessed the correlation of 67LR expression with clinical characteristics. In vitro experiment was performed for 67LR with inhibition using siRNA to evaluate its role in cell survival, apoptosis, and invasion in EOC cells.

Results

67LR was predominantly expressed on the cell membrane in the majority of EOC samples (45/62, 73%). 67LR expression was significantly correlated with advanced stage (P = 0.001). Patients with 67LR expression had shorter progression-free survival among all the patients (P = 0.010) and in particular among patients with advanced stages (P = 0.046). When 67LR expression was inhibited by siRNA in EOC cells (HeyA8 and A2780), there was a significant decrease of cell proliferation and invasion as well as increase of apoptosis.

Conclusion

These findings suggest that 67LR expression may play an important role in tumor progression into advanced stage with poor prognosis in EOC and down-regulation of 67LR on tumor cells may be a therapeutic target in those patients.     

Prognosis of ovarian clear cell carcinoma compared to other histological subtypes: a meta-analysis

Objective

To compare the survival outcome between clear cell carcinoma (CCC) and other histological subtypes in epithelial ovarian carcinoma (EOC).

Methods

From January 1974 to February 2011, we identified a total of 31,800 (CCC; 2152, non-CCC; 29648) patients from 12 studies meeting the inclusion criteria.

Results

Heterogeneity tests demonstrated significant between-study variation (I² = 92.1%) with no significant difference in hazard ratio (HR) for death between CCC and non-CCC (HR; 1.16, 95% CI; 0.85-1.57, random-effects model). Comparing the HR based on stage I + II, and stage III + IV, between CCC and non-CCC, showed that CCC patients had a higher hazard rate for death than those with non-CCC of the ovary (stage I + II; HR; 1.17, 95% CI; 1.01-1.36, stage III + IV; HR; 1.65, 95% CI; 1.52-1.79). In a comparison of CCC and serous EOC, advanced stage (III and IV) CCC only showed a poorer hazard rate for death than serous EOC (HR; 1.71, 95% CI; 1.57-1.86).

Conclusion

This analysis suggests that ovarian CCC patients had poorer prognosis than those with other histological subtypes of EOC, especially in advanced EOC stages. Different treatment strategies may be needed for patients with ovarian CCC.     

Differential expression patterns of CXCR3 variants and corresponding CXC chemokines in clear cell ovarian cancers and endometriosis

Objectives

Carcinogenesis of the ovary is often associated with endometriosis. We previously demonstrated that antitumor chemokine receptor CXCR3 was upregulated both in endometriosis and ovarian cancers. Currently, little is known about the roles of CXCR3 variants in these ovarian diseases. In this study, we investigated the expression of CXCR3 variants and their corresponding ligands in endometriosis and ovarian cancers.

Methods

The expression patterns of CXCR3 variants (CXCR3A, CXCR3B and CXCR3-alt) and their corresponding ligands were investigated by quantitative RT-PCR, Western blot and in situ hybridization in normal ovaries (n = 16), endometriosis (n = 12), and clear cell ovarian cancers (n = 22) including endometriosis-coexisting cases (n = 11).

Results

Sequence analysis of purified RT-PCR products confirmed the presence of three CXCR3 variants in human ovaries. Quantitative RT-PCR analysis revealed differential expression patterns of these variants depending on conditions. CXCR3A was upregulated both in endometriosis and cancers. On the other hand, CXCR3-alt was upregulated and CXCR3B was downregulated in cancers compared with endometriosis. The corresponding ligand CXCL11 was upregulated only in the cancers with elevated CXCR3-alt. Another ligand CXCL4 was downregulated in the cancers with suppressed CXCR3B. In situ hybridization demonstrated preferential expression of CXCR3A in cancer cells and infiltrating lymphocytes. CXCR3B and CXCR3-alt were detectable mainly in microvessels.

Conclusions

Collective data suggest that differential expression patterns of CXC chemokines and CXCR3 variants are involved in specific inflammatory microenvironment of ovarian cancers. Altered balance of CXCR3 variants may become helpful information for better understanding of the pathogenesis of ovarian cancers arising from endometriosis.     

Progranulin is a potential prognostic biomarker in advanced epithelial ovarian cancers

Objective

There are few validated relapse prediction biomarkers for epithelial ovarian cancer (EOC). We have shown progranulin (PGRN) and secretory leukocyte protease inhibitor (SLPI) are up regulated, overexpressed survival factors in EOC. We hypothesized they would predict presence of occult EOC.

Method

PGRN, SLPI, and the known biomarker HE4 were measured in EOC patient plasma samples, prospectively collected every 3 months from initial remission until relapse. Clinical data and CA125 results were incorporated into statistical analyses. Exploratory Kaplan-Meier estimates, dividing markers at median values, evaluated association with progression-free survival (PFS) and overall survival (OS). Area-under-the-curve (AUC) statistics were computed from receiver operating characteristic (ROC) curves to evaluate discrimination ability. A Cox proportional hazards model assessed the association between PFS, OS, and biomarkers, adjusting for clinical prognostic factors.

Results

Samples from 23 advanced stage EOC patients were evaluated. PGRN at 3 months was the only biomarker independently associated with PFS (P < 0.0001) and OS (P < 0.003). When used to predict progression by 18 months, sensitivity and specificity were 93% and 100%, respectively, with AUC = 0.944. The Cox model hazard ratio for PFS, divided at 59 ng/ml by ROC analysis and adjusted for clinical factors, was 23.5 (95% CI: 2.49-220). Combinations with SLPI, HE4, and/or CA125 did not improve the model.

Conclusions

We report pilot data indicating a potential independent association of PGRN on EOC patient PFS and OS. A validation study will be required to confirm this finding and to inform whether PGRN warrants evaluation as a potential screening biomarker.     

nm23 gene polymorphisms are associated with survival of patients with epithelial ovarian cancer but not with susceptibility to disease

Objective

nm23, a tumor metastasis suppressor gene, has been linked to protection against tumorigenesis and tumor metastasis. This study evaluated whether genetic variants in the nm23 gene were associated with susceptibility to epithelial ovarian cancer (EOC) or the clinical outcome of patients.

Methods

A case-control study was performed with 302 patients with epithelial ovarian cancer and 302 control women. According to the genotypes, the outcome in 213 EOC patients was compared. Progression-free survival (PFS) and overall survival (OS) were analyzed with Kaplan-Meier plots and Cox models adjusted for clinical factors.

Results

The case-control analysis showed that the rs16949649 and rs2302254 polymorphisms in the nm23 gene promoter were not associated with the risk of developing EOC. In contrast, survival analysis showed that the rs2302254 C/T polymorphism was related to the prognosis of EOC patients. Compared with patients carrying the C/C genotype, patients carrying the T/T genotype had a shorter median PFS and median OS by Kaplan-Meier plots and Cox models adjusted for clinical factors. For rs16949649 T/C polymorphisms, Kaplan-Meier analysis indicated that patients carrying the homozygous C/C genotype had shorter PFS and OS than those carrying the T allele (T/T + T/C genotype). The Cox proportional hazard model analysis suggested that this relationship was only retained in OS when adjusted for clinical factors.

Conclusion

Our studies suggest that rs16949649 and rs2302254 polymorphisms in the nm23 gene promoter may influence the prognosis of patients with epithelial ovarian cancer.     

Effect on ovarian reserve of laparoscopic bipolar electrocoagulation versus laparotomic hemostatic sutures during unilateral ovarian cystectomy

Objective

To compare the effects of laparoscopic bipolar electrocoagulation with laparotomic hemostatic suturing during unilateral ovarian cystectomy on the ovarian reserve.

Methods

A prospective randomized trial was conducted on 59 women with unilateral benign ovarian cysts who underwent laparoscopic ovarian cystectomy by a stripping technique (n = 30) or open laparotomy with hemostatic suturing (n = 29). Serum anti-Müllerian hormone (AMH), antral follicle count (AFC), and ovarian stromal peak systolic velocity (PSV) at the 1st, 3rd, and 6th postoperative cycle were used to assess the ovarian reserve.

Results

Preoperative AMH levels did not differ significantly (P = 0.18) between the laparoscopy and laparotomy groups. In the laparoscopy group, there was a significant decrease in AMH levels, AFC, and PSV at the 3rd and 6th postoperative cycles compared with the 1st postoperative cycle, with an insignificant decrease between the 3rd and 6th cycles. In the laparotomy group, nonsignificant decreases in AMH levels, AFC, and PSV were detected at the 1st, 3rd, and 6th postoperative cycle and between the 3rd and 6th cycles.

Conclusion

Laparoscopic ovarian cystectomy is associated with a significant reduction in ovarian reserve. This is a consequence of damage to the ovarian vascularity and the removal of an increased amount of ovarian tissue.     

Abnormal methylation patterns at the IGF2/H19 imprinting control region in phenotypically normal babies conceived by assisted reproductive technologies

Objective

To evaluate epigenetic risks linked to assisted reproductive technologies (ART) by determining the methylation status of the IGF2/H19 imprinting control region (ICR) in offspring born after ART.

Study design

A combined bisulfite restriction analysis (COBRA) and sequencing technique were used to determine the methylation status of the IGF2/H19 ICR in 61 phenotypically normal newborns conceived by ART. Thirty naturally conceived newborns were studied as controls.

Results

There was no significant difference in methylation between ART newborns and naturally conceived newborns (46.7 ± 8.2% vs. 48.5 ± 8.7%, p > 0.05). Abnormal demethylation patterns of the IGF2/H19 ICR were found in three dizygotic twins conceived by intracytoplasmic sperm injection (ICSI), but all three were phenotypically normal, and their sibling twins exhibited normal methylation patterns.

Conclusion

We hypothesize that the aberrant methylation patterns probably resulted from imprinting errors of paternal gametes or from in vitro embryo culture. Further investigation to determine whether gene expression can be regulated by other mechanisms in addition to DNA methylation would be beneficial.     

Prevalence of cysts in epithelial ovarian cancer

Objective

Ovarian carcinomas mostly appear as large cystic masses. However, the exact prevalence of cysts in epithelial ovarian cancer (EOC) has never been documented as well as the tumor factors that are related to the presence of cysts. Demonstrating the prevalence of cysts in EOC is essential for research focused on predictive and prognostic biomarkers in ovarian cyst fluid.

Study design

From 233 patients with primary EOC who underwent surgery, pathological data were collected from pathology reports. Univariate and multivariate logistic regression were used to analyze the relationship between the presence of cysts and other tumor characteristics.

Results

Cysts in EOC were present in 83.7% of the patients and were mostly (61%) multilocular. The most common histological subtypes (serous, mucinous, endometrioid, clear cell) contained cysts in more than 85% of the cases. In univariate regression analysis, early FIGO stage, low tumor grade and a large tumor size were significantly associated with the presence of cysts (OR (95% CI) = 5.312 (1.81-15.57), 6.906 (2.31-20.66) and 1.169 (1.08-1.27), respectively). In multivariate regression analysis, apart from tumor size, only tumor grade was independently associated with the presence of cysts (adjusted OR (95% CI) = 4.234 (1.36-13.22)).

Conclusions

The large majority of all EOCs contained cysts. Histological subtype, FIGO stage, tumor necrosis and age were not associated with the presence of cystic EOC. In contrast, tumor grade and tumor size were independently related to the presence of cystic EOC. This means that cystic EOCs represent a subgroup of larger and more well-differentiated tumors. The evident relationship between the presence of cysts and differentiation grade is interesting from a clinical point of view as grading is especially important for the prognosis and treatment of patients with stage I EOC.     

Methylation of HPV16 genome CpG sites is associated with cervix precancer and cancer

Objective.

Invasive cervix cancer (ICC) is the second most common malignant tumor in women. Human papillomavirus 16 (HPV16) causes more than 50% of all ICC and is a major cause of cervix intraepithelial neoplasia (CIN). DNA methylation is a covalent modification predominantly occurring at CpG dinucleotides. Such epigenetic modifications are associated with changes in DNA-protein interactions and gene activation. This study examined the association of viral and host genomic methylation patterns and cervix neoplasia.

Methods.

Exfoliated cervical lavage samples positive for HPV16 from women with and without cytomorphic changes of infection (n = 46), CIN2 (n = 12), and CIN3+ (n = 27) were used to interrogate the methylation patterns of the HPV16 L1 gene and upstream regulatory region (URR), five host nuclear genes (TERT, RARB, DAPK1, MAL, and CADM1), and mitochondrial DNA (mtDNA). DNA isolated from exfoliated cervicovaginal cells was treated with bisulfite, specific regions of the viral and host genome were PCR amplified and CpG methylation was quantified using EpiTYPER and pyrosequencing.

Results.

Methylation at 14 of the tested CpG sites within the HPV16 L1 region were significantly higher in CIN3+ compared to HPV16 genomes from women without CIN3+. In contrast, 2/16 CpG sites in HPV16 URR, 5/5 in TERT, 1/4 in DAPK1 and 1/3 mtDNA, and 2/5 in RARB were associated with increased methylation in CIN3+.

Conclusions.

These results indicate that increased methylation of CpG sites in the HPV16 L1 ORF is associated with CIN3+ and, thus, may constitute a potential biomarker for precancerous and cancerous cervix disease.     

Distinctive DNA methylation patterns of cell-free plasma DNA in women with malignant ovarian tumors

Objective

Epithelial ovarian carcinoma (OvCa) is rarely detected early, and it is also difficult to determine whether an adnexal mass is benign or malignant. Previously, we noted differences in methylation patterns of cell-free plasma DNA (cfpDNA) in women without disease compared to patients with OvCa. In this work, we investigated whether methylation patterns of cfpDNA can differentiate between benign and malignant tumors.

Methods

Methylation patterns in cfpDNA were determined in three cohorts (30 samples each) using a microarray-based assay (MethDet 56). Principal component analysis, supervised clustering, linear discrimination analysis, and 25 rounds of 5-fold cross-validation were used to determine informative genes and assess the sensitivity and specificity of differentiating between OvCa vs. healthy control (HC), benign ovarian disease (mostly serous cystadenoma, BOD) vs. HC, and OvCa vs. BOD samples.

Results

Differential methylation of three promoters (RASSF1A, CALCA, and EP300) differentiated between OvCa vs. HC with a sensitivity of 90.0% and a specificity of 86.7%. Three different promoters (BRCA1, CALCA, and CDKN1C) were informative for differentiating between BOD vs. HC, with a sensitivity of 90.0% and a specificity of 76.7%. Finally, two promoters (RASSF1A and PGR-PROX) were informative for differentiating between OvCa vs. BOD, with a sensitivity of 80.0% and a specificity of 73.3%.

Conclusions

This proof-of-principle data show that differential methylation of promoters in cfpDNA may be a useful biomarker to differentiate between certain benign and malignant ovarian tumors.

Research Highlights

? Methylation patterns in cell-free DNA from blood can detect ovarian tumors ? These patterns are different in patients with benign and malignant tumors ? Methylation of blood DNA can be used for differential diagnosis of ovarian cancer     

Cancerous inhibitor of protein phosphatase 2A is overexpressed in cervical cancer and upregulated by human papillomavirus 16 E7 oncoprotein

Objectives

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified oncoprotein stabilizing c-Myc and promoting cell proliferation and transformation. Here we investigated the role of CIP2A in cervical cancer in vivo and in vitro.

Methods

CIP2A expression was assessed in normal cervical, cervical intraepithelial neoplasia (CIN) I to III and cervical cancer tissues by immunohistochemistry and RT-PCR. Cell growth was explored by cell proliferation assay, colony formation assay and anchorage-independent growth in soft agar after inhibition of CIP2A by siRNA in HeLa, SiHa and Caski cells. Crosstalk of CIP2A and HPV16 E7 was investigated by immunohistochemistry in cervical cancer tissues and by real-time PCR and western blot analysis after HPV16 E7 inhibition by siRNA in SiHa cells.

Results

CIP2A was transcribed in 73.3% of cervical cancer tissues (n = 15) but not in normal cervical tissues (n = 8). CIP2A protein was detected in 52.8% of cervical cancer (n = 72) and 12.5% of CIN III tissues (n = 24) but not in normal (n = 15), CIN I (n = 21) or CIN II samples (n = 25). CIP2A protein level was positively associated with HPV16 E7 level in cervical cancer tissues. CIP2A expression was markedly reduced after E7 depletion. Moreover, CIP2A depletion reduced c-Myc protein level and impaired proliferation and growth of cervical cancer cells.

Conclusions

CIP2A is overexpressed in cervical cancer and promotes the malignant growth of cervical cancer cells. Its expression is upregulated by HPV16 E7. Therefore, CIP2A plays an important role in carcinogenisis of cervical cancer and shows promise for the diagnosis and treatment of cervical cancer.