Former British No 1 Elena Baltacha has revealed she has been diagnosed with cancer of the liver.
The 30-year-old said in a statement: "I have recently been diagnosed with cancer of the liver. I'm currently undergoing treatment and fighting this illness with everything I have."
Judy Murray, captain of the Great Britain Federation Cup team, said: "Obviously this is a tough time for Bally, her husband Nino and her family but she is a such a determined, upbeat person and everyone around her is staying positive as well.
"I know she'll be really grateful for all the support that she's getting."
British number three Heather Watson said: "It's terrible news to hear, and it must be so tough for her. I just wish her all the best. A good recovery. We'll all be thinking of her.
"I played doubles with her and won in Fed Cup in Sweden. I have been around her a lot. And especially being British and British tennis, all of us girls are very close.
"We will be sending our thoughts and prayers out to her. She has a real fighting spirit."
Baltacha retired from the circuit last year after struggling to overcome a series of injuries.
Following her retirement, Baltacha developed an academy for junior players in Ipswich.
The daughter of former Ipswich, St Mirren and Inverness footballer Sergei, she reached a career-high world ranking of 49 in 2010, and beat the likes of Li Na and Francesca Schiavone.
Baltacha, a hugely popular player on the circuit, was British No 1 from December 2009 to June 2012 - 132 weeks - and she won 11 ITF titles.
She played 39 times for Britain in the Fed Cup from 2003 to 2012 and was also part of Team GB at the London 2012 Olympics.
She was diagnosed at the age of 19 with primary sclerosing cholangitis, a chronic liver condition which compromises the immune system.