Prognostic and Therapeutic Relevance of PELP1 in Estrogen Receptor Positive Breast Cancer: A Systematic Review

Introduction: PELP1 is an oncogenic scaffold protein characterized by proline-, glutamic acid-, and leucine-rich domains, and serves as a crucial coregulator of the estrogenic receptor (ER). It facilitates tumour growth, metastasis, and a worse prognosis in ER+ breast cancer. This review examines PELP1 expression, prognostic relevance, and therapeutic potential, integrating prior studies to underscore its clinical importance. Methods: This systematic review includes publications from 2014–2024, retrieved via database searches using keywords like “PELP1,” “ER-positive breast cancer,” and “PELP1 expression” on PubMed, Google Scholar, and ScienceDirect. Articles were selected based on their relevance to PELP1 expression and its correlation with tumour behaviour and survival outcomes in ER+ breast cancer. Results: Six studies were identified that investigated the correlation between PELP1 levels and breast cancer outcomes. Findings suggest that elevated PELP1, particularly in the NH2 region, is associated with larger tumours, higher grade, and poorer prognosis. A statistical link was found between high PELP1 expression and elevated estrogen levels in ER+ tumours. However, small sample sizes and the absence of validation cohorts limit the conclusion. Discussion: Evidence suggests that PELP1 enhances ER signaling and may contribute to endocrine resistance. Its dual genomic and non-genomic roles underline its potential as a biomarker and therapeutic target. Conclusion: Although preliminary findings may indicate that PELP1 has the potential to be a clinically useful biomarker and therapeutic target for ER+ breast cancer, the current studies fail to sufficiently demonstrate that PELP1 is clinically beneficial. There is a need for more research with larger, more reliable group samples and more involved mechanistic studies.