Bioinformatics-Based Discovery of CKLF-Like MARVEL Transmembrane Member 5 as a Novel Biomarker for Breast Cancer

Chemokine-like factor (CKLF)-likeMARVELtransmembrane members (CMTMs) represent a novel protein family linking the chemokine and transmembrane-4 superfamily families, which potentially play several roles in diverse physiological and pathological processes. The detailed functions and underlying molecular mechanisms ofCMTMsremain elusive in breast cancer. Herein, we performed a comprehensive bioinformatic analysis to investigate the prognostic effect, potential functions, and biomolecular regulatory network ofCMTMsin breast cancer. The mRNA expression level ofCMTM5, in particular, was significantly downregulated in breast cancer; moreover, high mRNA expression level ofCMTM5was significantly associated with better relapse-free survival. DNA promoter hypermethylation ofCMTM5was negatively correlated with its mRNA expression levels. Furthermore,CMTM5strongly associated with pathway in MARVEL domains, chemotaxis, cytokines, transmembrane structures, and integral component of membrane. For example, genes related to MARVEL domains, transmembrane structures, and chemokines were significantly enriched. Our findings indicate thatCMTM5can be used as a prognostic biomarker and potential therapeutic target for breast cancer.