Ubiquitin-conjugating enzyme 2M (UBE2M), a critical E2 conjugating enzyme in the neddylation pathway, has emerged as a pivotal regulator of cancer progression through its involvement in ubiquitination/neddylation cascades, oncogene-tumor suppressor interactions, and cellular homeostasis. This review synthesizes current evidence on UBE2M's molecular roles in cancer, including its function in protein degradation, cell cycle control, and metabolic reprogramming. We further explore its diagnostic utility as a biomarker, and therapeutic potential as a target for small-molecule inhibitors and combination therapies. By integrating findings from preclinical models and clinical datasets, this review establishes UBE2M as a multifaceted node in cancer biology with significant implications for personalized oncology.