Parramatta co-captain Tim Mannah has expressed his family’s disappointment at reports linking his late brother Jon’s cancer battle with alleged peptide use at Cronulla NRL club.
Serious doubts also emerged on Friday about the link between peptide use and the increased likelihood of a relapse or onset of lymphoma.
Jon Mannah died from Hodgkin’s lymphoma earlier this year, aged 23.
He had recovered from a first bout of the lymphoma in 2009 to play the first five NRL matches of 2011.
News Ltd newspapers on Friday published a leaked extract from an independent report commissioned by the Cronulla club into alleged use of peptides in the club’s supplements program in 2011.
It questioned whether Jon Mannah’s cancer relapse could be linked to peptide use.
But leading cancer expert Professor Robert Baxter described the link as “tenuous at best”.
According to Baxter, children undergoing treatment for leukaemia are occasionally treated with growth hormones to help give them normal growth.
Professor Baxter described that process as “highly controversial” but stressed there was no evidence that there was any risk – and pointed out peptide injections would promote even less potential risk.
“That’s when the link is getting totally tenuous,” Professor Baxter, from the Kolling Institute, Royal North Shore Hospital, told AAP.
“You could then say that theoretically this growth hormone could then make the body produce insulin-like growth factors and they could stimulate the cancer growth.
“It’s a very long bow to draw, a really a tenuous link and a theoretical argument you could construct.
“But I’m saying there is no evidence that it’s a genuine risk.”
The Cancer Council also responded, releasing a statement which read: “Based on an assessment of the evidence available, Cancer Council Australia says there isn’t any link between HGH promoting peptides and a relapse or onset of lymphoma.”
That provided little relief for the grieving Mannah family, with Tim forced to defend his late brother’s integrity.
“On behalf of my family, I would like to say how disappointed we all are by the reports that have been published today,” Tim said.
“My brother Johnny was a wonderful man and never, ever would have knowingly consented to taking a banned substance.
“In fact, he was very careful about everything he did that may affect his health.
“Johnny’s integrity in the way he lived his life speaks for itself.
“We have no need to defend that.”
The Sharks’ world was turned upside after they were caught up in the investigation into the use of prohibited substances by the Australian Sports Anti-Doping Authority (ASADA) in February.
The Sharks were implicated due to their connection with controversial sports scientist Stephen Dank, who worked briefly with the club in 2011.
Dank has strongly denied ever giving banned substances to NRL players and Cronulla staff and players have denied knowingly administering or taking illegal substances.
The Mannah family also offered their support to Eels trainer Trent Elkin, who was employed by the Sharks during the period under ASADA investigation.
“Trent has had a long and trusted relationship with me, my brother and our family and what has transpired over the last day has not changed that,” the statement read.
“We know Trent does not condone the use of illegal substances and would have never knowingly done anything that would cause one of his players or Jon, for that matter, harm.”