Clinicopathological and Prognostic Significance of Melatonin Receptor MT1 (MTNR1A) Expression in Breast Cancer Patients: A Systematic Review
Tan Deasy Tandika Wijaya1,2, Aditya Sita Sari1,3*, Fishella Aprista Rahmanti1,2
Abstract
Background: Breast cancer caused 0.67 million deaths in 2022, and clinicians need tissue markers that refine risk beyond stage, hormone receptors, and HER2. Melatonin inhibits breast cancer growth through the MT1 receptor (MTNR1A), yet tissue studies disagree on its prognostic value. Objective: To evaluate the clinicopathological and prognostic significance of MT1 expression in breast cancer. Material and Method: Following PRISMA 2020, we searched PubMed, ScienceDirect, and Europe PMC for observational studies reporting MT1 expression in breast carcinoma tissue with clinicopathological or survival data. We assessed quality with the Newcastle-Ottawa Scale (NOS) and synthesized findings narratively. Eight studies (n = 657) met the criteria; three scored 9/9 and four scored 2/9. MT1-positive tumors ranged from 48.4% to 93.9%, and three studies found lower expression in triple-negative breast cancer (TNBC). High MT1 predicted longer overall survival (OS) in ER-positive patients (HR 0.42; 95% CI 0.21–0.87; p = 0.019) and tamoxifen-treated patients (HR 0.43; 95% CI 0.21–0.90; p = 0.025). In TNBC, MT1 negativity predicted shorter OS (adjusted HR 2.02; p = 0.026) and progression-free survival (adjusted HR 1.91; p = 0.034). A luminal cohort (n = 118) found no survival association (OS: HR 1.001; p = 0.624). We did not pool the data because antibodies, cut-offs, and outcome definitions differed across studies. Conclusion: Most breast carcinomas express MT1, with lower levels in TNBC. MT1 is a candidate prognostic marker, but its survival evidence rests on two retrospective cohorts with different methods. Clinical use requires validated MT1-specific antibodies and standardized cut-offs.
Keywords
breast cancer; MTNR1A; melatonin receptor; prognosis
Cite This Article
Wijaya, T. D. T., Sari, A. S., Rahmanti, F. A. (2026). Clinicopathological and Prognostic Significance of Melatonin Receptor MT1 (MTNR1A) Expression in Breast Cancer Patients: A Systematic Review. International Journal of Scientific Advances (IJSCIA), Volume 7| Issue 5: Sep – Oct 2026, Pages 669-682. URL: https://www.ijscia.com/wp-content/uploads/2026/10/Volume7-Issue5-Sep-Oct-No.1088-669-682.pdf
Volume 7 | Issue 5: Sep – Oct 2026
