Study documents sperm changes years after chemotherapy

Sperm from former chemo patients had similar pattern of molecular changes

Epigenetic changes in the sperm of males who undergo chemotherapy in their teens can influence how their genes are turned on and off, potentially affecting the health of tissues in subsequent generations. That’s according to a new study co-authored by Dr. Stephen Schwartz of the Fred Hutch Public Health Sciences Division and led by researchers at Washington State University and Seattle Children’s.

headshot photo of Dr. Stephen Schwartz
Dr. Stephen Schwartz Photo by Bo Jungmayer / Fred Hutch News Service

Published Wednesday in the online journal PLOS One, these findings suggest that male teens about to undergo chemotherapy may consider having some of their sperm preserved for when they would like to start a family, said senior author Dr. Michael Skinner, a professor in the WSU School of Biological Sciences and Center for Reproductive Biology.

The study examined sperm from 18 males who had undergone chemotherapy as adolescents and 18 untreated men whose sperm served as a comparison, or control. Skinner and colleagues at WSU collaborated with researchers at Seattle Children’s Research Institute and Schwartz of Fred Hutch, whose role was to recruit some of the control subjects, given his prior experience recruiting young men for studies involving biospecimens.

While the sample size was small, all of the sperm from the former chemotherapy patients had a similar pattern of molecular changes.

While direct exposure to chemotherapy could affect a lot of cells, those effects should have disappeared within months, as the testes take 75 days to make sperm, which remain in the body for 20 or 30 more days. So, for effects to be seen 10 years later, cells in the testes must be permanently altered, according to the researchers.

The researchers next plan to investigate what effects, if any, these changes are having on subsequent generations – both in chemotherapy patients and their offspring, as well as similar changes in rodents.

“This study represents the first observation in humans that an early life chemical exposure can permanently reprogram the spermatogenic stem cell epigenome,” the researchers wrote. “The germline (i.e. sperm) epimutations identified suggest chemotherapy has the potential to promote epigenetic inheritance to the next generation.”

The National Institutes of Health and Childrens Oncology Group funded the research.

— Adapted from a Washington State University news release

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