A hand that clasps yours can save your life if the hand belongs to a perceptive general practitioner, as it happened in the case of English restauranteur Mark Gurrieri.
As he casually shook hands with Dr Chris Britt, the GP noticed a 'fleshy and spongy' feeling which instantly triggered his professional concern.
A glance at Gurrieri's large facial features all but confirmed his suspicions and set alarm bells ringing.
Dr Britt had recognised the symptoms of acromegaly, a life-threatening disease caused by a benign brain tumour that affects just three people in every million, reports Daily Mail from the UK.
The chance meeting led to Mr Gurrieri visiting his own GP, who referred him to a specialist, and the growth was removed last month.
The life-saving handshake happened on December 6, when lifelong friend Rob Thompson brought Dr Britt to an Italian restaurant Mr Gurrieri runs in Canary Wharf.
"I came out to meet them at the door. My friend, Rob, brought Chris along for the first time," he said.
"We shook hands and I sat them down at the table. He didn't say anything to me at the time but he turned to Rob as soon as he sat down and said 'I'm sure he has acromegaly, I can tell you. I'll stake my career on it.'
"Rob didn't tell me straight away. He came in two days later and was really nervous about telling me.
"I got straight on the internet. I read down the lines and saw the word 'tumour'. That word is frightening, especially when it has to do with the head.
"I went to my GP with everything I could print off from the internet and waved it under his nose.
"He looked it up and said he wasn't sure but would send me off for a blood test and MRI scan. They came back positive for acromegaly."
The condition, in which a tumour grows on the pituitary gland, causes an increase in growth hormones that can cause giantism in children.
In adults, it causes soft tissues to be deposited in the hands and growth of the skull bones.
Other symptoms include blindness, diabetes, high blood pressure and weakening of the heart and kidney. If left untreated it can lead to premature death.
Mr Gurrieri, 36, from Loughton, Essex, who is divorced with one son, is believed to have had the condition for up to five years before it was diagnosed.
He said he had been feeling under the weather for some time and would fall asleep at a moment's notice.
"I always had big hands but I noticed in recent years they had become quite chunky. I put it down to doing all kinds of things at home and working in the kitchen," he added.
"I had noticed my face becoming more fleshy too. I went to a school reunion last year and I recognised everyone but I thought it was strange that no one recognised me.
"I also had muscle definition like I had been on steroids. I went to play golf with a friend who I hadn't seen for a couple of years and he asked if I had been going to the gym."
uring an operation in Wellington Hospital in St John's Wood, north London, on January 14, a pituitary surgeon managed to remove 92 per cent of the tumour.
Gurrieri now takes medication and has to be monitored to keep the condition under control.
Dr Britt said: "As soon as I saw him I thought he looked like somebody who had acromegaly. When I shook his hand it felt fleshy, which is caused by the soft tissue being deposited.
"When I was a medical student I was at Barts Hospital in London where I saw a few people with the condition because it is a specialist centre for treating it. But it is extremely rare."
Gurrieri added: "My mum thinks Chris is my guardian angel. I think I owe my life to him - and a few meals at the restaurant."