The human ageing processes may hinder cancer development, according to a recent study. The research, published in the journal Ageing Cell, noted that each cell in the human body is specialised to carry out certain tasks and would only need certain genes to be activated to accomplish them.
The researchers, including those from the University of Liverpool in the UK, said that analysis of gene expression -- the process by which genes were activated to produce a required protein -- was often used to study cancer and ageing.
However, they added that only a few studies investigated the relationship between gene expression changes in ageing and cancer. The researchers compared how genes were differentially expressed with age, and also how their expression changed in cancer among nine human tissues.
Normally, the study noted that a healthy cell could divide in a controlled manner whereas in senescent or 'sleeping' cells, they lost their ability to divide. The number of senescent cells in our bodies increases as we age, driving many age-related processes and diseases, the researchers said.
Genetic mutations, the study noted, caused cells to replicate uncontrollably, leading to cancer. The researchers said that cells often detect these mutations and go to sleep to stop the proliferation. However, they found that in most of the tissues examined, ageing and cancer gene expression "surprisingly changed in the opposite direction."
According to the researchers, the changes happening in cells as one ages might relate to a decrease in cell division, while cancer changes this shift towards an increase in proliferation. "One of the reasons our bodies have evolved to have senescent cells is to suppress cancers. But then it seems that senescent cells accumulate in aged human tissues and may contribute to ageing and degeneration," said Joao Pedro De Magalhaes, co-author of the study from the University of Liverpool.
The study, he said, challenged the traditional view concerning the relationship between cancer and ageing and suggested that the ageing processes may hinder cancer development. "While mutations accumulate with age, and are the main driver of cancer, ageing tissues may hinder cell proliferation and consequently cancer," he added.
De Magalhaes said that the two forces oppose each other with mutations driving cancer, and tissue degeneration hindering it. "This may explain why at very advanced ages cancer incidence levels off and may even decline," he said.
The researchers said that the complex relationship between ageing, cancer and cellular senescence suggested that in most human tissues, the ageing processes and senescence act in tandem while also being detrimental to cancer.