Low Levels of Protein Marker Could Predict Radiotherapy Benefit for Breast Cancer

A new study suggests that low levels of the PDGFRb protein are associated with particularly positive results of radiotherapy in women with early-stage breast cancer, according to a press release from Karolinska Institutet and Gothenburg University in Sweden.

Standard treatment for ductal carcinoma in situ (DCIS)—the earliest possible form of invasive breast cancer—includes surgery and subsequent radiotherapy. Although patients typically have a good prognosis, about 10% suffer a recurrence within a decade of their diagnosis, according to the researchers.

“It is well-known that the benefits of radiotherapy are individual, so we need to find predictive markers that can be used to avoid unnecessary or ineffective radiotherapy,” said co-last author Fredrik Warnberg, MD, in the press release.

To this aim, previous studies have focused mainly on markers within the tumor cells themselves. Recent research, however, has shown that supporting tissue around the tumor cells can affect the therapeutic effect of DCIS. Studies in cell and animal models have demonstrated that the efficacy of radiotherapy can be influenced by fibroblasts, which are a type of supporting cell in breast cancer tissue.

The investigators at Karolinska Institutet and researchers with Warnberg’s group have now analyzed a large tissue collection from a randomized radiotherapy study. They found that low levels of PDGFRb are associated with especially high radiotherapeutic efficacy for women with DCIS. These findings also suggest that the efficacy of radiotherapy can be improved with drugs that block this protein.

Several studies have been launched in order to further investigate this link.

“The treatment guidelines of DCIS might need to be changed if these studies confirm our original findings,” said first author Carina Strell, PhD, in the press release.

REFERENCE

New marker predicts benefit of radiotherapy for early-stage breast cancer [news release]. Karolinska Institutet; May 5, 2021. https://news.ki.se/new-marker-predicts-benefit-of-radiotherapy-for-early-stage-breast-cancer. Accessed May 7, 2021.