The clinicopathological and prognostic significances of CMTM6 and PD-L1 expression in breast cancer

Background Chemokine-like factor-like MARVEL transmembrane domain-containing 6 (CMTM6) is recognized as a critical regulator of programmed cell death ligand 1 (PD-L1) protein expression, which serves an essential role in regulating the tumor immune response. The objective of the present study was to analyze CMTM6 and PD-L1 expression and their clinicopathological significance in breast cancer development. Immunohistochemistry was performed to detect CMTM6 and PD-L1 expression in breast cancer tissues and their mRNA expression was analyzed using databases. Furthermore, the correlation between CMTM6 and PD-L1 expression and infiltration by immune cells was evaluated. Results The results revealed that CMTM6 and PD-L1 expression was higher in breast cancer tissues than in normal tissues. Additionally, CMTM6 and PD-L1 expression was positively associated with lymph node metastasis, TNM stage, vascular infiltrationand HER2 positivity in patients with breast cancer. Lymph node metastasis and histological grade were identified as risk factors that affect patient survival time. The Kaplan–Meier plotter database revealed that CMTM6 and PD-L1 mRNA expression was positively associated with poor prognosis in patients with breast cancer. Furthermore, the tumor immune estimation resource database indicated that CMTM6 and PD-L1 were closely related to six immune cell types, and their expression levels were positively correlated in breast cancer. Conclusions The present findings suggested that CMTM6 and PD-L1 expression is involved in the genesis and development of breast cancer, and CMTM6 and PD-L1 could be used as novel molecular markers for early diagnosis of breast cancer.