CELLULAR TIMEKEEPERS: CIRCADIAN RHYTHM DISRUPTIONS AND THEIR ROLE IN CANCER METASTASIS

Abstract

The circadian rhythm, an intrinsic 24-hour biological clock, orchestrates fundamental cellular functions including metabolism, DNA repair, cell cycle progression, and immune surveillance. This internal timekeeping system is governed by a set of core clock genes such as CLOCK, BMAL1, PER, and CRY, which maintain physiological homeostasis through transcriptional-translational feedback loops. However, disruptions to this rhythm — caused by environmental factors such as shift work, exposure to artificial light at night, jet lag, or genetic mutations — can profoundly influence cancer development and progression. Recent research indicates that circadian rhythm disruption (CRD) not only contributes to tumor initiation but also plays a pivotal role in promoting cancer metastasis, the process through which malignant cells spread from primary tumors to distant organs, often leading to poor patient outcomes and increased mortality.