Science Bites seeks to compile the latest scientific research updates in bite-sized forms.

1. Novel blood test alerts recurrence of malignant melanoma

Random mole growths should be looked into before it is too late – as one in every three cancers diagnosed is estimated to be a skin cancer1.

Fortunately, UK-based researchers have pioneered a novel blood test that detects genetic mutations BRAF and NRAS – two genes that account for over 70% of malignant melanoma cases. This simple test detects the presence of circulating tumour DNA in patients with resected melanoma in order to predict the chances of recurrence2.

Over the course of five years, 33% of participants who tested positive for faults in either of the two genes were alive, compared to 65% of those who tested negative. The test also proved to be a strong prediction tool for disease recurrence in one year – 74% of those who were positive relapsed at one year, compared to the 26% of those who were negative2.

“We have no accurate tests to predict when cancers will return. If we can use this tumour DNA test to accurately predict if cancer is going to come back, then it could help doctors decide which patients could benefit from new immunotherapies,” comments lead researcher, Professor Richard Marais3.

“These treatments can then reduce the risk of the cancer spreading. The next step is to run a trial where patients have regular blood tests after their initial treatment has finished in order to test this approach3," he adds.

2. Key pathway in UV-induced skin cancer unlocked

DNA damaged by UVB radiation forms a dimer. Photo credit: Clinuvel
DNA damaged by UVB radiation forms a dimer. Photo credit: Clinuvel

As rapid industrialisation continuous to wreak havoc on the ozone layer – experts estimate that with every 10% of decrease in ozone, there is an additional 4,500 melanoma and 300,000 non-melanoma cancer cases1. It is also an established fact that UV rays cause skin cancer – but how exactly does that happen?

Researchers from Cornell University, US believe that they have found the answer. Under normal circumstances, exposure to the sun triggers melanocytes to produce melanin which results in just a tan. However, in melanocytes that have accumulated various genetic mutations, UV light could trigger a cascade of events that eventually results in melanoma4.

One genetic factor, known as Hmga2, has recently been identified as the key factor required for melanoma to develop. Mice that were altered to not have Hmga2 – but still possess all other mutations associated with melanoma – were found to be resilient against this cancerous growth. Surprisingly, these mice did not develop the cancer but similarly altered mice that had Hmga2 did4.

With regards to future potential of this discovery, senior author of the study Andrew White says, “We have an actual mechanism, with Hgma2, that can be explored in the future and could be a way we can prevent melanomas from happening5.”

Fluorescence microscopy reveals melanoma (red, left; black, right) emerging from melanocyte stem cells. Photo credit: Hyeongsun Moon and Andrew White/Cornell UniversityMedicalXpress
Fluorescence microscopy reveals melanoma (red, left; black, right) emerging from melanocyte stem cells. Photo credit: Hyeongsun Moon and Andrew White/Cornell UniversityMedicalXpress

3. Common antihypertensive may be associated with skin cancer

A nationwide study in Denmark recently found that long term use of hydrochlorothiazide resulted in the surprising risk of developing basal cell carcinoma (BCC) and a much higher risk of developing squamous cell carcinoma (SCC)6.

In an analysis of over 80,000 cases of skin cancer, researchers found that a cumulative dose of more than 50,000mg (which equals to approximately 2000 daily doses over six years) were enough to confer risks of getting skin cancer. These findings were dose-dependent, as those who have used more than 200,000mg cumulatively stand to slightly higher chances of developing BCC, but doubles their risks of developing SCC6.

"We knew that hydrochlorothiazide made the skin more vulnerable to damage from the sun's UV rays, but what is new and also surprising is that long-term use of this blood pressure medicine leads to such a significant increase in the risk of skin cancer," comments Anton Pottegård, Associate professor of the University of Southern Denmark and initiator of the study7.

Hydrochlorothiazide is an extremely common diuretic and antihypertensive that is used by over 10 million people annually in the US. While authors warn against abruptly ceasing medication, they also advise patients to discuss this issue with their doctor7. MIMS

Read more:
New technology allows for diagnosis of skin cancer without biopsy at NCS Singapore
Other factors that increase skin sensitivity to UV rays
Epigenetic drugs: The promise of future precise cancer treatments

Sources:
1. http://www.who.int/uv/faq/skincancer/en/index1.html
2. https://academic.oup.com/annonc/advance-article/doi/10.1093/annonc/mdx717/4589598
3. https://medicalxpress.com/news/2017-12-blood-skin-cancer.html
4. https://www.ncbi.nlm.nih.gov/pubmed/29033353
5. https://www.rdmag.com/article/2017/10/researchers-discover-how-uv-rays-cause-skin-cancer
6. http://www.jaad.org/article/S0190-9622(17)32741-X/pdf
7. https://www.sciencedaily.com/releases/2017/12/171204105339.htm
8. http://www.clinuvel.com/science-of-skin/skin-sun/skin-cancer/uv-damage-and-carcinogenesis?print=1&tmpl=component
9. https://medicalxpress.com/news/2017-10-uv-rays-trigger-skin-cancer.html