The Potential of Differentiation-Related Gene-1 (DRG1) as a Biomarker for Metastasis of Estrogen Receptor-Positive Breast Cancer

Introduction: Breast cancer is major burden worldwide and the majority of breast cancers express estrogen receptors (ER) suggesting a high dependence on estrogen hormone. Age is among the major determinants of breast cancer development, however, although Western Kenya is one of the areas with high breast cancer cases, age distribution of ER-positive breast cancer in the sub-region remains largely undocumented. Differentiation-related gene-1 (DRG1) is a metastasis suppressor and thus a potential biomarker for predicting level of metastasis but its potential application in assessing extent of metastasis of ER positive breast cancer has not been fully explored. This study therefore investigated the age distribution and the potential of expression of DRG1 in assessing metastasis of ER positive breast cancer.

Materials and Methods: Breast cancer tumour blocks archived in safe cabins in the histology laboratory section, Moi Teaching and Referral hospital, Eldoret, Kenya were used. Clinico-pathological parameters such as histology grade, tumor size, which are associated with metastatic cancer, were assessed using the archived clinico-pathological reports and/or histological analysis of the tumour blocks. Expression of DRG1 and Ki-67 proteins were determined using immunohistochemistry.

Results: ER positive breast cancer was predominant among women aged 40 and 50 years. No association was observed between immunohistochemical expression of DRG1 and parameters such as histology grade, tumor size or expression of Ki-67 protein expressed DRG1 (p > 0.05).

Conclusion: The findings suggest that expression of DRG1 protein is not associated with parameters that indicate breast cancer metastasis. Thus, DRG1 expression is not a potential biomarker candidate for ER positive breast cancer metastasis. However, since the small sample size was used, further research using larger prospective study is necessary to support the present findings.