The family of a man who died after receiving a liver transplant from a donor with undetected cancer has called for more thorough tests.
Tom Tyreman, 63, from Stockton, initially recovered after the operation at Newcastle's Freeman Hospital a year ago, but died of cancer in February.
There was later found to be a small cancerous tumour in the donor organ that was not picked up by screening.
The hospital said the "tragic outcome" could not have been anticipated.
NHS Blood and Transplant Service said it does everything it can to make sure all donated organs are suitable, but because of the sudden and speedy nature of organ donation it was not normally possible to screen a donor in advance.
Pauline Hunt, 49, from Kilmarnock, has also developed cancer after receiving a kidney from the same donor; a woman who died from a blood clot.
Mr Tyreman's sister, Jane Bird, said hospital staff needed to be "more upfront" about what could potentially go wrong.
"We were told that he could develop cancer further down the line because his immune system was so suppressed, which we accepted", she said.
"But we were never told that potentially he could get it from the donated organ.
"I think there need to be more stringent tests. It's just unacceptable in this day and age that more vigorous tests cannot be done."
An NHS Blood and Transplant spokesman said the medical history of potential donors is "carefully checked" and if an abnormality is found a biopsy is carried out.
But "in very rare cases it's possible the donor has a small tumour which can't be picked up by the tests performed in the limited time available prior to transplant".
"This means the transmission of an undiagnosed cancer is a risk, though thankfully it's extremely rare."