Aggressive Breast Cancer Diagnosis May Be Thwarted By Vitamin D Receptor Protein

Researchers found that expression of the vitamin D receptor (VDR) protein may help protect against aggressive forms of breast cancer. The study was first published online in Clinical Cancer Research, a journal of the American Association for Cancer Research (AACR).

“A complex interplay exists among vitamin D, hormone receptors and the development and progression of breast cancer cells,” says the study’s senior author, Song Yao, PhD, Associate Professor of Oncology in the Department of Cancer Prevention and Control at Roswell Park, in a news release. “This study offers new and valuable insights into the mechanisms of vitamin D and the influence this important micronutrient has on aggressive breast cancer subtypes.”

VDR expression in breast tumors was determined by examining 1,114 female patients using immunohistochemistry (IHC) and looking for low, moderate, and strong expression. The results showed that 58% of breast tumors had moderate or strong VDR expression. VDR expression was inversely related to aggressive tumor characteristics, including large tumor size, hormonal receptor (HR) negativity, and triple-negative subtype (P < .05). VDR expression was also inversely related to Ki-67 expression among patients older than 50 years.

Although this finding has not yet been linked to improved patient survival, this is promising for follow-up studies.

“We speculate that the tumor vitamin D receptor levels might change throughout the course of the disease, are modified by circulating vitamin D levels, or are subject to molecular controls by vitamin D, genetic variations and other factors. Further studies are needed to elucidate the mechanisms impacting the regulation of vitamin D receptor expression in breast tumors,” said Yao.

This may leave people wondering about vitamin D supplementation via sunlight or vitamins as a prevention strategy. The National Cancer Institute notes that incidence and death rates for certain cancers are shown to be lower among people living in southern latitudes, where levels of sunlight exposure are relatively high compared to those living in northern latitudes, and so researchers hypothesized that variation in vitamin D levels might account for this association. However, additional research based on stronger study designs will help to determine whether higher vitamin D levels are related to lower cancer incidence or death rates.