Role of epigenomics in ovarian and endometrial cancers

Ovarian cancer is the most lethal gynecologic malignancy and while constituting only 3% of all female cancers, it causes 14,600 deaths in the USA annually. Endometrial cancer, the most diagnosed and second-most fatal gynecologic cancer, afflicts over 40,000 US women annually, causing an estimated 7780 deaths in 2009. In both advanced ovarian and endometrial carcinomas, the majority of initially therapy-responsive tumors eventually evolve to a fully drug-resistant phenotype. In addition to genetic mutations, epigenetic anomalies are frequent in both gynecologic malignancies, including aberrant DNA methylation, atypical histone modifications and dysregulated expression of distinct microRNAs, resulting in altered gene-expression patterns favoring cell survival. In this article, we summarize the most recent hypotheses regarding the role of epigenetics in ovarian and endometrial cancers, including a possible role in tumor 'stemness' and also evaluate the possible therapeutic benefits of reversal of these oncogenic chromatin aberrations.

Emerging promise of epigenetics and DNA methylation for the diagnosis and management of women's cancers

Over the last two decades, survival rates from women's cancers (breast, ovarian, endometrial and cervical cancer) have all but modestly improved despite huge efforts from both research and clinical communities. In parallel with this, the field of epigenetics has grown from its infancy into a promising scientific discipline. In particular, DNA methylation analysis has been adopted by oncologists in an attempt to better understand and manage cancer. Now that the epigenetic technological base has caught up, the potential of methylation markers in cancer research is finally being realized. In this review, we present the current status of epigenetic research into women's cancers with a main focus on DNA methylation analysis. We provide an overview of technological development, current markers of risk prediction, early detection, diagnosis, prognosis and response to treatment, and highlight the progression of epigenetic therapies. Finally, we comment on the potential impact of epigenetic analyses on the future of women's health.

Interventions for the treatment of borderline ovarian tumours

BACKGROUND

The safety of conservative surgery and the benefit of additional interventions after surgery for borderline ovarian tumours are unknown.

OBJECTIVES

To evaluate the benefits and harm of different treatment modalities offered for borderline ovarian tumours.

SEARCH STRATEGY

We searched the Cochrane Gynaecological Cancer Group Trials Register to 2009, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 4), MEDLINE and EMBASE to 2009. We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared different interventions in adult women diagnosed with borderline ovarian tumours of any histological variant.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted data and assessed risk of bias.

MAIN RESULTS

We identified seven RCTs that enrolled 372 women. We could not pool results of trials as the treatment comparisons differed.Six RCTs (n = 340) conducted over 15 years ago, evaluated adjuvant therapy (chemotherapy, pelvic external irradiation or intra-peritoneal radioactive isotope therapy) after radical surgery; over 87% of participants had Stage I tumours. Most participants were followed up for over 10 years. Overall and recurrence-free survival were similar between both arms of these trials, except that one trial (n = 66) showed a significantly lower survival (P = 0.03) in women who received chemotherapy (thio-TEPA). Adverse effects of treatment were incompletely reported and all six trials were at high risk of bias.One further trial (n = 32) that recruited participants with bilateral serous tumours who were wishing fertility preservation, revealed a significantly increased chance of pregnancy (hazard ratio (HR) = 3.3, 95% CI 1.4 to 8.0) but non-significantly earlier disease recurrence (HR = 1.5, 95% CI 0.6 to 3.8) in the women who had ultra-conservative surgery (bilateral cystectomy) than in those who had conservative surgery (cystectomy and contralateral oophorectomy). This trial was at low risk of bias.Quality of life (QoL) was not documented in any included trial. We did not find any trials that compared radical with conservative surgery or laparoscopy with laparotomy.

AUTHORS' CONCLUSIONS

We did not find evidence to support the use of any specific type of adjuvant therapy for borderline ovarian tumours. RCTs evaluating the benefit of adjuvant therapy with optimally dosed chemotherapy and newer targeted drugs are necessary, particularly for advanced borderline ovarian tumours. The low mortality from borderline ovarian tumours should make recurrence-free survival, time to recurrence and morbidity important end points in such trials.Bilateral cystectomy may be offered to women with bilateral borderline ovarian tumours diagnosed intra-operatively who are wishing to preserve their fertility. Similarly, women who had RCTs comparing radical with conservative surgery and comparing laparoscopy with laparotomy are needed.

The biology of ovarian cancer: new opportunities for translation

Over the past two decades, the 5-year survival for ovarian cancer patients has substantially improved owing to more effective surgery and treatment with empirically optimized combinations of cytotoxic drugs, but the overall cure rate remains approximately 30%. Many investigators think that further empirical trials using combinations of conventional agents are likely to produce only modest incremental improvements in outcome. Given the heterogeneity of this disease, increases in long-term survival might be achieved by translating recent insights at the molecular and cellular levels to personalize individual strategies for treatment and to optimize early detection.

Histone deacetylase inhibitors as anti-neoplastic agents

Histone deacetylase inhibitors (HDACIs) constitute a novel class of targeted drugs that alter the acetylation status of histones and other important cellular proteins. These agents modulate chromatin structure leading to transcriptional changes, induce pleiotropic effects on functional pathways and activate cell death signaling in cancer cells. Anti-neoplastic activity in vitro was shown in several experimental models of cancer, but the exact mechanism of cytotoxicity and responses are not clearly understood. Phase I/II clinical trials of various HDACIs as single agents conducted to date have shown substantial activity in cutaneous T cell lymphoma (CTCL), preliminary activity in Hodgkin's disease and modest activity in myeloid neoplasms. Responses have been rare in solid tumors. Several agents are being tested in combination therapy clinical trials, either as chemosensitizers for cytotoxic chemotherapy or radiation therapy, or in association with DNA methylation inhibitors based on in vitro synergy. In this review, we focus on recent basic and clinical data that highlight the anti-neoplastic role of HDACIs.

Histone deacetylase inhibitors in cancer therapy

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of recent advances in the development of histone deacetylase inhibitors (HDACi) for the treatment of cancer.

RECENT FINDINGS

Recently, there has been a dramatic expansion of HDACi clinical investigation. There are now 11 HDACi in clinical trial, including inhibitors with a broad spectrum of HDAC isoform inhibitory activity as well as drugs with isoform selectivity. Over 70 combination therapy trials are in progress. Major areas of progress covered include the entry of new HDAC inhibitors into clinical development, recent progress in understanding of molecular mechanisms of HDACi anticancer activity, and a preclinical and clinical update on HDACi in combination.

SUMMARY

In the period under review there have been advances in understanding of HDACi mechanisms of action, identification of rational combinations that address increased efficacy and overcoming resistance, and greatly expanded clinical development of pan-HDAC-inhibitory and isoform-selective inhibitors in monotherapy and combination therapy protocols.