A study utilizing the research resources of BioBank Japan (BBJ) has been published in NPJ-Aging.

A research team led by Adjunct Assistant Professor Takuro Kobayashi and Visiting Associate Professor Tsuyoshi Hachiya of Graduate School of Medicine, Juntendo University focused on the phenomena of mosaic loss of chromosome Y (mLOY)—the loss of part of the Y chromosome in blood cells—reported to increase among male cancer patients after diagnosis. mLOY is recognized as a risk factor for cancer and mortality. 

The team analyzed DNA from 348 prostate cancer patients treated at Juntendo University Hospital to examine the frequency of mLOY across different cancer treatment modalities. They found that patients who underwent local radiotherapy showed a significantly higher prevalence of mLOY compared with those who did not receive this treatment. 

This association was further confirmed in a large-scale data set of over 30,000 patients with prostate, lung, colorectal, and gastric cancers from BioBank Japan. For the first time, large-scale data analysis has suggested that radiation therapy may exacerbate genomic instability, indicating a potential vulnerability in certain cancer patients to DNA damage induced by radiation therapy.

Original Paper

Local radiotherapy for cancer patients is associated with mosaic loss of chromosome Y, a hallmark of male aging
NPJ Aging. 2025 Jul 29;11(1):69

Press release article from the University of Tokyo (Japanese only)

https://www.ims.u-tokyo.ac.jp/imsut/jp/about/press/page_00350.html