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LONDON — Hepatitis B and C viruses can cause multiple myeloma, one of the most common cancers of the blood, according to a study that opens up new treatment options for the fatal disease.
The finding is based on a patient who, a few years ago, was cured of multiple myeloma after being treated for hepatitis C, astounding a team of Spanish researchers.
It is unknown what causes multiple myeloma, and although it has long been suspected to be related to infectious pathogens, this connection has never been verified or the reason understood.
The team from Hospital 12 de Octubre (H12O) and the National Cancer Research Centre (CNIO) in Madrid, Spain found that eliminating infection with antivirals is often the way to fight this type of cancer.
"The recognition of this association between viral hepatitis and multiple myeloma, as well as the pathologies known to precede the appearance of myeloma, monoclonal gammopathies, has important clinical implications," the team wrote in an editorial in the journal Haematologica.
"Early identification of Hepatitis B or C virus infection in these individuals can lead to appropriate antiviral treatment and consequent improvement in outcomes," they added.
Multiple myeloma (MM) is an excessive proliferation of blood cells that make antibodies (also called immunoglobulins), the proteins that defend the body from infections.
In myeloma, a certain antibody -- different in each case, depending on the infectious agent -- is produced continuously and excessively. One theory proposes that this anomaly is due to chronic exposure to the infectious agent, which alters the biochemical signals involved in the production of the specific antibody against that agent.
The case of the patient who was cured of myeloma after being treated for Hepatitis C seems to support this theory.
The team conjectured that the body was no longer chronically exposed to the Hepatitis virus because the antiviral drug eliminated it, and that is why the myeloma disappeared -- the cells that make anti-Hepatitis C antibodies stopped reproducing in excess.
To investigate whether this had actually happened, two studies were conducted, including 54 patients with monoclonal gammopathy (the pathology that precedes multiple myeloma) and hepatitis: 9 patients with Hepatitis C in an initial study, and 45 patients with Hepatitis B in the study published in Haematologica. Most of them found that the antibody they were consistently and excessively producing was indeed targeting the hepatitis virus. They then went on to analyse a much broader cohort of multiple myeloma patients (more than 1,300) infected with Hepatitis B and Hepatitis C (more than 1,200).
In both cohorts, they concluded that in those who received antiviral treatment "the probability of survival was significantly higher".
"In patients infected with the Hepatitis B or Hepatitis C virus, multiple myeloma or gammopathy may be caused by these viruses, and the study demonstrates the importance of antiviral treatment in these patients," the researchers said.