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Ovarian Cancer & BRCA: How Genetic Screening Can Save Lives

Posted on by Jnetics
29
Sep

by Josh Forman, Head of Science, Education & Outreach

Ovarian cancer is a major killer.

Around 7,500 people are diagnosed with ovarian cancer every year. It is the sixth most common form of cancer in females, accounting for 4% of all cancer in females (1). 11% of these cancer cases are preventable – that’s approximately 825 people every year with preventable ovarian cancer.  

Being a BRCA gene fault carrier is a major risk factor for developing ovarian cancer. This is also true of Lynch Syndrome, which is based on another set of genes that predispose carriers to a host of cancer types (such as bowel cancer).

Ovarian cancer is both preventable and/or treatable when you are aware of your risk, and it is caught early.

The key symptoms to look out for are:

  • bloating
  • stomach pain
  • difficulty eating
  • needing to urinate more frequently

If you notice any of these symptoms, contact your GP. Others symptoms that can be associated are back pain, changes in bowel habits, extreme tiredness or unexplained weight-loss (2, 3).

Fundamentally, cancer is when our cells start to break down, and an accumulation of genetic mutations acquired throughout our life happen to hit specific genes. The key genes in question encode a group of proteins that check the health, status and viability of cells’ DNA, and thus control it’s replication to produce new cells.

When healthy, these genes, known as oncogenes and tumour suppressor genes, proofread our entire DNA code, looking for mistakes. If they find mistakes (which they invariably do, because DNA is so complex) they either fix the DNA or signal the cell to be destroyed via a process called apoptosis (programmed cell death). This prevents cancer developing.

However, if there is a mistake in one of these genes, the proof-reading proteins cannot work properly, and more and more mutations are allowed to ‘slip through the net’. Therefore, the cells become more and more damaged.

The next step is that the tumour suppressor genes cannot put the brakes on cell division (mitosis) in a damaged cell. This is the step that controls whether the cell undergoes division. Hence the name – they suppress tumours forming. When the tumour suppressor genes are broken, there are no brakes on the cell division.

This means that there is uncontrolled cell division, so the cell that is damaged is replicated too fast, and too many times. This is the basis of a tumour. This is Stage 1.

If this is allowed to continue unchecked, the tumours become larger and larger, and cause secondary problems such as blocking blood vessels and organ function etc. There comes a point where the tumours stimulate the growth of blood vessels, and behave almost as an organ in their own right. The next step is that cells break off the tumour, travel in the blood and settle elsewhere in the body. This is Stage 4, and termed metastatic.

BRCA is a tumour suppressor. If you carry a variation in your BRCA 1 or 2 gene, it means that you are particularly susceptible to developing a mutation in your second BRCA 1 or 2 gene.

Ovarian cancer is one the cancers that is directly impacted by BRCA. If you carry a BRCA variation, your risk of developing ovarian cancer is increased to 44% (36-53%) with BRCA1, and 17% (11-25%) with a BRCA2 variation. Alongside this stat, 40% of ovarian cancer cases in the UK Jewish community are BRCA related. 

If you test positive for a BRCA mutation through the NHS Jewish BRCA Testing Programme, you are entered into the NHS High Risk Screening Programme. This screening programme is geared towards breast cancer, as there is currently no effective and reliable screen for ovarian cancer on the NHS, however there are currently studies being conducted into ovarian cancer screening, focused on a blood test and a transvaginal ultrasound. (4,5)

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