Health issues

Deadly discovery: Study finds 45 new genes linked to greater skin cancer risk

Aug 07, 2019

Australian researchers have discovered 45 new genetic causes of Basal cell carcinoma and squamous cell carcinoma skin cancers. Source: Getty

Skin cancer is a major problem in Australia and around the world and while the majority of skin cancers are caused by too much exposure to the sun, Australian researchers have discovered 45 new genetic variants that put people at greater risk of developing the most common forms of the disease – Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

The new research from the QIMR Berghofer Medical Research Institute more than doubles the genetic information now available on these cancers.

BCCs develop in the lower layer of the epidermis in areas exposed to the sun such as the head, face, neck and shoulders. They tend to grow slowly, don’t typically spread to other parts of the body and appear as either a pearly lump or a dry, scaly area of pink skin. SCCs on the other hand form in the upper layer of the epidermis and grow quickly in areas exposed to the sun, typically appearing thick, red and like a sore.

The exact number of people diagnosed with the non-melanoma skin cancers is unknown, but researchers say it makes up more than all other cancers combined. Worryingly, the Australian Institute of Health and Welfare predicts 714 people will die by the end of 2019 due to BCCs and SCCs, while the direct Medicare costs for BCCs and SCCs currently exceed $100 million in Australia.

Meanwhile the total associated costs of diagnosis, treatment and pathology is more than $700 million – making them the nation’s most expensive cancers.

For the latest study, researchers analysed 48,000 people from Australia, the United Kingdom and the United States who were treated for BBCs or SCCs, with senior study author Stuart MacGregor explaining: “We compared the genetic information of patients treated for BCCs and SCCs to that from 600,000 people without these cancers – which allowed us to identify which genes were different between the two groups.

“We identified 45 new genes which had not previously been linked to these cancers. Most affected both BCCs and SCCs, although a few were specific to one or the other. Previously only about 40 genetic variants for these skin cancers had ever been identified.”

The research, published in the Human Molecular Genetics Journal, acknowledges that ultra violet exposure is the biggest risk factor for developing skin cancer, but explains that there are also important inherited contributions underlying BCCs and SCCs. It’s now thought the new genetic variants will help explain why some people develop skin cancers, while others with similar features such as light skin or freckles don’t.

“On the flip side, although the study looked only at the genetic information of light skinned people, identification of genetic markers could also explain why some people with darker skin types still get BCCs and SCCs,” lead researcher Upekha Liyanage said. “Currently there’s no genetic testing for skin cancers, but if we can get a clearer understanding of which genes are responsible and where on the DNA these genes are located, other scientists can start working on finding better treatments and preventative strategies.”

The latest study is the largest to date to investigate the genetic variants influencing BCCs and SCCs and could be used to repurpose existing treatments or to develop new ones. And, while the genetic variants play a significant role in understanding skin cancer, researchers warn that ultraviolet exposure remains the single biggest cause of skin cancers.

The best way to protect against the sun’s harmful rays is to wear protective clothing, SPF30 or higher broad spectrum sunscreen, a broad-brimmed hat, sunglasses and seeking shade where possible. The earlier skin cancer is detected, the easier it is to treat, so it’s always important to chat with a GP or dermatologist as soon as you notice any changes in the skin.