The 31-year-old, who made 15 appearances for Rovers between 2011-12, returned abnormal blood tests during pre-season training with his current club, Championship outfit Wolverhampton Wanderers and was diagnosed with leukaemia after further medical investigation.
Ikeme will now start a course of chemotherapy as he begins his battle against the disease.
Wolves revealed the news in a statement on Thursday afternoon.
"It would be an understatement to say that everyone at Wolves has been shocked and saddened to hear the news of Carl's diagnosis,' said managing director Laurie Dalrymple.
"That relates to both players and staff as Carl has been at the club for a very long time and remains such an integral personality within the group.
"At the same time, we all know what a fighter and a competitor Carl is, and I have no doubt that he will take all of those attributes into this battle.
'Similarly, its goes without saying that Carl and his family will receive the full love and support that we at Wolves can provide – we are all with him every single step of the way towards a full recovery.
"There are going to be some very tough times ahead, but he will receive the best possible care, aided and supported by our own club doctor and medical team, as he embarks on the lengthy process of treatment.
'We are speaking to Carl regularly, and sending him our very best wishes as he comes to terms with this news and starts his recovery."
The statement continued: 'Carl and his family would request that their privacy be respected at this time, and any updates on his progress will be provided through the club.
"Anyone wishing to send messages of support can do so to [email protected] and we will pass them on to Carl at the appropriate time."
Ikeme has made 200 appearances at Wolves and has spent time on loan at a number of other clubs.