Translucent image of a woman's torso showing triple negative breast cancer in one breast
Credit: Science Photo Library - ROGER HARRIS/Getty Images

Researchers at the Hunan Normal University in China have discovered that the expression levels of a protein called retinitis pigmentosa GTPase regulator interacting protein 1-like (RPGRIP1L) may serve as a new prognostic marker for invasive breast cancer (BRCA).

Published in The FASEB Journal, the study suggests that RPGRIP1L could provide crucial insights into patient outcomes and guide the development of targeted therapies.

RPGRIP1L is known for its various roles in development and health throughout life, particularly for helping to maintain the structure and function of cilia, which are hair-like projections on cell surfaces important for cell signaling and movement. Variants of the RPGRIP1L gene have been linked to several diseases, but its correlation with invasive breast cancer had not been previously explored.

By examining breast tissue specimens from different women, investigators found that RPGRIP1L expression was significantly elevated in invasive breast cancer specimens compared to normal breast tissue. Furthermore, a notable decline in survival rates was observed in patients with heightened RPGRIP1L gene expression, highlighting its potential as a prognostic marker.

The study also revealed that elevated RPGRIP1L expression was associated with a spectrum of unfavorable clinicopathological features. These included the presence of human epidermal growth factor receptor 2 (HER2) positive, estrogen receptor (ER) positive cancers, patients over 60 years old, and specific tumor stages such as T2, N0, and N3. According to the researchers, this suggests that high RPGRIP1L levels may indicate more aggressive cancer forms and larger tumors.

In addition to its role in prognosis, the research identified 50 genes and 15 proteins whose expression levels were positively correlated with RPGRIP1L. Many of these genes and proteins are involved in critical biological processes, such as T cell proliferation, immune response, cytokine activity, and metabolic regulation.

The study also found a significant correlation between RPGRIP1L expression and immune cell infiltration, suggesting that RPGRIP1L may influence the tumor microenvironment and immune response in breast cancer.

Finally, the research team explored potential therapeutic strategies and identified four compounds—abrine, epigallocatechin gallate, gentamicin, and tretinoin—that showed potential for reducing RPGRIP1L expression in laboratory experiments. These compounds could form the basis of new treatment strategies aimed at modifying RPGRIP1L levels to influence disease progression and improve survival rates for breast cancer patients.

“The findings of our research underscore the potential of RPGRIP1L as a significant prognostic biomarker for breast cancer and suggest the viability of novel therapeutic strategies that may modify disease progression, thus potentially enhancing survival rates among affected individuals,” concluded co-corresponding author Jie Zeng, PhD, of the First Affiliated Hospital of Hunan Normal University in a press statement.

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