Former McLaren doctor Aki Hintsa is battling cancer.
The 56-year-old Finn stepped away from F1 at the end of 2013, although he continued to treat various current drivers at his clinic in Geneva.
Now, the Finnish newspaper Turun Sanomat reports that Dr Hintsa has begun a fight against cancer, after an abdominal tumour was diagnosed.
He has reportedly already started treatment, including chemotherapy, in a Geneva hospital, and correspondent Heikki Kulta said Hintsa is "optimistic".
"Dr Aki Hintsa was diagnosed very recently with a malignant tumour in his upper abdomen," a spokesman for Hintsa Performance told GMM.
"Doctors have started comprehensive medical treatment and considering the circumstances Aki is doing well. He is in good spirits and has continued working to date.
"Aki will now focus on his family, recovery and prioritised workload. He is extremely grateful for the enormous support he has been receiving from the F1 paddock," the spokesman added.