Hugh Jackman feared earlier this week he had a basal cell carcinoma, the most common type of skin cancer, for the third time in 10 years.

Thankfully for the Australian actor, he underwent two biopsies and the results came back negative on Thursday.

“Thank you all for the love. I feel it!” said the 54-year-old, who is preparing to play Wolverine, a character from the X-Men film franchise, in Deadpool 3.

“Please remember to wear sunscreen with a high level of SPF (no matter the season),” he added, in a note posted to Instagram on Thursday.

But his words about preventing skin cancer are still worth heeding.

In a video shared on Monday, wearing a bandage on his nose,  Jackman said his doctor “saw little things, could be or could not be basal cell in her opinion. She doesn’t know”.

Jackman reminded fans and people at large to protect themselves while outdoors.

“Please wear sunscreen. It is just not worth it. No matter how much you want to tan, trust me, trust me, trust me,” he said.

“Put some sunscreen on. You’ll still have an incredible time out there. Please be safe.”

Basal cell carcinomas

Basal cells are in a layer at the bottom of the epidermis, the outer-most layer of skin.

They produce new skin cells. These new cells push older cells upward to the skin’s surface, where they die and are sloughed off.

A basal cell carcinoma (BCC) occurs when a basal cell develops a mutation in its DNA. This mutation causes the basal cell to multiply rapidly and to keep growing instead of naturally dying.

Unless this process runs out of steam, these rapidly accumulating abnormal cells form a tumour or carcinoma. The cancer appears as a lesion on the skin.

It’s often removed with surgery, sometimes in a GP’s surgery.

What causes the mutation?

Ultraviolet light from too much exposure to the sun, or from commercial tanning beds gets most of the blame.

Hence, Jackman’s wise advice that we wear a high-factor sunscreen when outdoors.

BCCs commonly appear on the head or neck, or anywhere that has been exposed to sunlight.

However, these skin cancers can develop on parts of your body not often exposed to sunlight, including the genitals. Why this occurs isn’t always clear.

How do I know I have a basal cell carcinoma?

BCCs can look different from one person to another. Basically, any sore spot or growth on the skin should be checked out by your doctor.

A BCC can be a shiny bump or nodule.

According to the Skin Cancer Foundation, for which Jackman is an ambassador, BCCs can be “open sores, red patches, pink growths, shiny bumps, scars or growths with slightly elevated, rolled edges”.

They may have a central indentation.

At times, BCCs may ooze, crust, itch or bleed.

In people with darker skin, about half of BCCs are pigmented or brown in colour.

A reddish patch or irritated area can be a BCC.

How dangerous are they?

A BCC is rarely fatal, but it can be locally aggressive, and even disfiguring.

According to Johns Hopkins Medicine, these cancers rarely metastasise to lymph nodes or other organs, but it does happen.

They can grow quite large and invade small nerves and local structures.

Low-risk tumours are often nodular and do not have nerve involvement.

Tumours that are recurrent or arising from previously radiated tissue are considered high risk. As are tumours arising in patients who are immuno-suppressed.

Risk factors

• Chronic sun exposure
• Radiation therapy to treat acne or other skin conditions may increase the risk of basal cell carcinoma at previous treatment sites on the skin
• Fair skin, red or blonde hair, or light-coloured eyes
• Increasing age. BCC often takes decades to develop and the majority of basal cell carcinomas occur in older adults. But it is becoming more common in people in their 20s and 30s
• A personal or family history of skin cancer
• Exposure to arsenic beyond that which occurs naturally
• Inherited syndromes that cause skin cancer, such as nevoid basal cell carcinoma syndrome (Gorlin-Goltz syndrome) and xeroderma pigmentosum.

Link to other cancers

According to a 2018 study from Stanford University:

People who develop abnormally frequent cases of BCC appear to be at significantly increased risk of developing other cancers including blood, breast, colon and prostate cancers.

A 2012 study from Brown University found that for many people BCC is more of a chronic disease.

High sun exposure before the age of 30 was a major predictor, as was a history of eczema.