Summer is almost here, and many of us have been waiting what seems like a long time to get into the great outdoors. As enjoyable as it may seem, we do want to avoid too much sun.
It is not new news that one should avoid turning their skin into leather over the summer. The ancient Greeks are alleged to have used olive oil to keep their skin moisturized from the sun. However, it was not until 1974 that the concept of sun protection factor (SPF) was introduced. SPF is not a precise measurement and ongoing research will no doubt help us in the future. Too much exposure to the sun can lead to wrinkles, moles and skin cancer.
Moles, brown spots and growths on the skin are usually harmless — but not always. On a recent visit to my doctor, I learned the ABC’s of melanoma.
- A – Asymmetrical Shape… Look at the moles on your body. Probably the majority are symmetrical and therefore most likely benign. If they appear to be irregular, then they should be investigated.
- B – Border… Most non-cancerous moles are smooth and have even borders. Melanoma on the other hand displays as irregular borders that are difficult to define.
- C – Colour… A warning sign of melanoma is the appearance of more than one colour or an uneven distribution of colour. Benign moles are usually a single shade of brown or tan.
- D – Diameter… It is a dangerous sign if you see a mole that is bigger than a pencil eraser.
- E – Evolution… Most important, keep an eye on what is your normal. If a mole has gone through recent changes in colour and/or size, bring it to the attention of your doctor immediately.
I met Peter Rice last year: our paths converged at a lunch spot in County Cork. I quickly learned that he had bicycled across Canada in 2015 to raise awareness for melanoma. I’ve since come to associate him with the phrase: “Know the skin you are in”. He tweets about the risks and detection of melanoma. Peter especially warns us that exposure to ultraviolet radiation from the sun and the use of tanning beds are among the most important risk factors for melanoma.
Last year, 7,200 Canadians were diagnosed with melanoma, and 1,250 died from the disease. Let’s look at some of what we know about the genomics of melanoma.
Most associated with melanoma is the CDKN2A gene mutation. When functioning properly, this gene on chromosome 9 is a suppressor gene. It controls cell growth. A mutation increases the risk of cancer. Some variants of the gene are passed along. It has been found that about 5%–25% of families with a higher risk for melanoma have an inherited gene mutation in the CDKN2A gene.
There are two genes found on chromosome 16 that also play a role in melanoma risk. The MC1R gene is linked with skin and hair pigmentation. People with an MC1R variant that causes red hair and fair skin may have a higher risk of developing melanoma. The ERCC4 gene codes for a protein that is involved in the 5' incision made during nucleotide excision repair. This loss of DNA repair may lead also lead to melanoma risk.
Also associated with DNA repair mechanisms is the WRN gene which codes as the Werner protein, a helicase enzyme, which helps maintain the structure and integrity of a person's DNA. It may also play a role in aging. This gene is found on chromosome 8.
Also found on chromosome 8 is the RB1CC1 gene. This gene’s protein interacts with signaling pathways to regulate cell growth, cell proliferation, apoptosis, autophagy, and cell migration. Mutations in this gene not only increase the risk of melanoma, it is associated hereditary retinoblastoma with a type of eye cancer that affects children.
It is going to be a beautiful summer out there, but recall the words of Peter Rice, “know the skin you are in”.
Links of interest:
Canadian Cancer Society
Peter Rice on Twitter
Peter cycles across Canada - interview