SCIENCE / HODGKIN’S DISEASE : USC Study of Twins Points to Heredity’s Role

USC researchers have found new evidence that heredity can play a role in the development of Hodgkin’s disease, a cancer of the lymphatic system that carries water, proteins and electrolytes from tissue fluids into the blood.

In a study of 432 sets of twins in which one sibling developed the disease, Dr. Thomas Mack and his colleagues at the USC School of Medicine found 10 cases in which the other sibling also developed Hodgkin’s.

In each of the 10 cases, the sibling was an identical twin, which means both came from the same fertilized egg. There were no sets of fraternal twins in which both twins had the disease.

The researchers said the findings, which are to be published today in the New England Journal of Medicine, show that “genetic susceptibility underlies Hodgkin’s disease in young adulthood.”

Doctors have long suspected a genetic component to the disease because having a brother or sister with it increases an individual’s risk of developing Hodgkin’s sevenfold.

The Mack study has “addressed this problem in a comprehensive and systematic way,” according to an editorial in the Journal by Drs. Volker Diehl and Hans Tesch of the University of Cologne in Germany.

But the disease may also have an environmental component. A virus or some other organism that most people shake off may spark Hodgkin’s in a person who is genetically vulnerable.

Other researchers have uncovered evidence that higher social class or having a small number of brothers and sisters increases the risk of Hodgkin’s for young adults.

“These results indicate that the disease may be a rare consequence of a common infection, analogous to paralytic poliomyelitis,” in which the likelihood of cancer increases if the infection strikes later in life, Diehl and Tesch said.