Germline and somatic genetic testing in ovarian cancer patients

Somatic mRNA Analysis of BRCA1 Splice Variants Provides a Direct Theranostic Impact on PARP Inhibitors

BACKGROUND

The identification of pretherapeutic somatic BRCA variants can have considerable clinical impact given that they affect response to the new poly (ADP-ribose) polymerase (PARP)-targeted therapy. One major issue with this type of testing is the identification of splicing variants of uncertain significance (VUS) on degraded somatic messenger RNA. It is therefore important to be able to quickly characterize these splice variants.

OBJECTIVE

As part of PARP inhibitor targeted therapy, we have investigated a method for the direct confirmation of potential pathogenic somatic splice variants of BRCA1 found in fixed tumor samples. Previously these VUS have commonly only been tested by in silico analysis.

METHODS

Five BRCA1 variants affecting splicing were characterized from formalin-fixed, paraffin-embedded (FFPE) ovarian carcinoma tissues by next-generation sequencing (NGS). Three patient samples had already been functionally characterized and were used as controls. Total somatic RNA from samples was extracted, reverse-transcribed, and amplified with several primer pairs encompassing the target exon. The polymerase chain reaction (PCR) products were analyzed by capillary gel electrophoresis to assess possible changes in size due to splicing alterations. Finally, we confirmed our results by cloning, followed by Sanger sequencing, and analyzed the expression of the aberrant forms.

RESULTS

Our molecular approach made it possible to visualize the splicing outcomes of three variants (c.5194-2A>G, c.5434C>G, and c.547+1G>A) already identified and present in databases and/or identified with prediction tools (ClinVar, UMD, ARUP Utah database, and Human Splice Finder splices sites prediction) and to confirm their exon skipping consequences, their expression in tumors, and thus their pathogenicity. The c.4484+5G>A variant was not found in databases and was predicted to have no impact on splicing, but was found to display altered processing in tumor tissue. This variant also had a major detrimental impact on transcriptional expression.

CONCLUSION

In a break from purely in silico approaches, we propose a simple and rapid pretherapeutic functional analysis of somatic BRCA1 variants potentially involved in splicing alterations. This approach will allow more ovarian cancer patients to benefit from new therapies targeting PARP.

Women's Intentions to Engage in Risk-Reducing Behaviours after Receiving Personal Ovarian Cancer Risk Information: An Experimental Survey Study

Simple Summary

Risk stratification using genetic testing to identify women at increased risk of ovarian cancer may increase the number of patients to whom risk-reducing surgery (e.g., salpingo-oophorectomy) may be offered. However, little is known about public acceptability of such approaches. Our online experimental survey aimed to explore whether women aged 45–75 in the general population are willing to undergo ovarian cancer risk assessment, including genetic testing, and whether women’s potential acceptance of risk-reducing surgery differs depending on their estimated risk. We looked at whether psychological and cognitive factors mediated women’s decision-making. The majority of participants would be interested in having genetic testing. In response to our hypothetical scenarios, a substantial proportion of participants were open to the idea of surgery to reduce risk of ovarian cancer, even if their absolute lifetime risk is only increased from 2% to 5 or 10%.

Abstract

Risk stratification using genetic and/or other types of information could identify women at increased ovarian cancer risk. The aim of this study was to examine women’s potential reactions to ovarian cancer risk stratification. A total of 1017 women aged 45–75 years took part in an online experimental survey. Women were randomly assigned to one of three experimental conditions describing hypothetical personal results from ovarian cancer risk stratification, and asked to imagine they had received one of three results: (a) 5% lifetime risk due to single nucleotide polymorphisms (SNPs) and lifestyle factors; (b) 10% lifetime risk due to SNPs and lifestyle factors; (c) 10% lifetime risk due to a single rare mutation in a gene. Results: 83% of women indicated interest in having ovarian cancer risk assessment. After receiving their hypothetical risk estimates, 29% of women stated they would have risk-reducing surgery. Choosing risk-reducing surgery over other behavioural responses was associated with having higher surgery self-efficacy and perceived response-efficacy, but not with perceptions of disease threat, i.e., perceived risk or severity, or with experimental condition. A substantial proportion of women age 45–75 years may be open to the idea of surgery to reduce risk of ovarian cancer, even if their absolute lifetime risk is only increased to as little as 5 or 10%.