Genome Biology volume 21 , Article number: Cite this article. Metrics details. Biological rhythms regulate the biology of most, if not all living creatures, from whole organisms to their constitutive cells, their microbiota, and also parasites. Here, we present the hypothesis that internal and external ecological variations induced by biological cycles also influence or are exploited by cancer cells, especially by circulating tumor cells, the key players in the metastatic cascade.
We then discuss the possible clinical implications of the effect of biological cycles on cancer progression, and how they could be exploited to improve and standardize methods used in the liquid biopsy field. Recently, Thomas et al.
From precancerous lesions to metastatic cancers, oncogenic processes are very frequent in humans and animals [ 4 , 5 ], and not just during aging as often thought in the past [ 6 ]. From an evolutionary perspective, the transformation of normal cells into malignant cells that will form a cancer is equivalent to a speciation event inside the body [ 7 , 8 ], preceded by a set of mutations that allow normal cells to acquire self-defined fitness functions and on which natural selection can act [ 9 ].
As the holobiont components are usually prisoners of their host, their environment is composed of at least two very different ecological dimensions: the host i. The first type of environmental variables that holobiont members experience are the host physiological, genetic, and phenotypic characteristics, such as sex, age, and immunocompetence.
The second level of environmental variability is due to the biotic and abiotic factors that characterize the ecosystem in which the host lives resource level, abundance of predators, seasons. These intra- and inter-individual variables and their interactions contribute to the selective landscape in which holobiont members survive and maximize their lifetime reproductive success i. An interesting direction in this research area concerns the influence of the biological rhythms that coordinate organismal activities with the environment circadian rhythms.
