Tumour heterogeneity is a phenomenon where each cell that makes up a tumour,contains mutations that differ from that of other cells in the tumour.The clonal evolution and cancer stem cell theories of cancer formation,...Tumour heterogeneity is a phenomenon where each cell that makes up a tumour,contains mutations that differ from that of other cells in the tumour.The clonal evolution and cancer stem cell theories of cancer formation,have been used to explain tumour heterogeneity.The theories both point to the existence of cells within a tumour that are capable of initiating the tumour in a different location.While the clonal evolution theory argues that all cells within a tumour possess this ability,the cancer stem cell theory argues that only a few cells(cancer stem cells or CSCs)within the tumour possess this ability to seed the tumour in a different location.Data supporting the cancer stem cell theory is accumulating.Researchers have targeted these CSCs therapeutically,hypothesizing that since these CSCs are the‘drivers’of tumour progression,their death may inhibit tumour progression.This was foiled by tumour cell plasticity,a phenomenon whereby a non-CSC spontaneously de-differentiates into a CSC.Researchers are now working on combinations that kill both CSCs and non-CSCs as well as drugs that prevent non-CSC-to-CSC transition.This review concisely describes CSCs and how they contribute to the difficulty in treating cancer.展开更多
It is well known that with increasing age,the risk of acquiring certain age-related diseases e such as diabetes,cancer,cardiovascular disease and neurodegenerative diseases,increases.Several theories have been propose...It is well known that with increasing age,the risk of acquiring certain age-related diseases e such as diabetes,cancer,cardiovascular disease and neurodegenerative diseases,increases.Several theories have been proposed to explain the reason why ageing leads to higher susceptibility to disease.Over time,many of these theories have been proven wrong.Currently,the two theories holding the interest of researchers in this field are the oxidative damage theory and hyperfunction theory of ageing.The former is an old theory which explains that ageing is as a result of oxidative damage(to macromolecular components of the cell)by reactive oxygen species produced as a normal part of metabolism.The hyperfunction theory is a much newer theory which explains that ageing is as a result of the unnecessary and unwanted continuation of certain metabolic processes at old age.In this review,we discuss the mechanisms which underlie the development of age-related cancer.We also discuss the aforementioned theories of ageing.We conclude by explaining the opposing views of proponents of both theories and provide a new viewpoint by revealing a point of synergy in the two theories.展开更多
文摘Tumour heterogeneity is a phenomenon where each cell that makes up a tumour,contains mutations that differ from that of other cells in the tumour.The clonal evolution and cancer stem cell theories of cancer formation,have been used to explain tumour heterogeneity.The theories both point to the existence of cells within a tumour that are capable of initiating the tumour in a different location.While the clonal evolution theory argues that all cells within a tumour possess this ability,the cancer stem cell theory argues that only a few cells(cancer stem cells or CSCs)within the tumour possess this ability to seed the tumour in a different location.Data supporting the cancer stem cell theory is accumulating.Researchers have targeted these CSCs therapeutically,hypothesizing that since these CSCs are the‘drivers’of tumour progression,their death may inhibit tumour progression.This was foiled by tumour cell plasticity,a phenomenon whereby a non-CSC spontaneously de-differentiates into a CSC.Researchers are now working on combinations that kill both CSCs and non-CSCs as well as drugs that prevent non-CSC-to-CSC transition.This review concisely describes CSCs and how they contribute to the difficulty in treating cancer.
文摘It is well known that with increasing age,the risk of acquiring certain age-related diseases e such as diabetes,cancer,cardiovascular disease and neurodegenerative diseases,increases.Several theories have been proposed to explain the reason why ageing leads to higher susceptibility to disease.Over time,many of these theories have been proven wrong.Currently,the two theories holding the interest of researchers in this field are the oxidative damage theory and hyperfunction theory of ageing.The former is an old theory which explains that ageing is as a result of oxidative damage(to macromolecular components of the cell)by reactive oxygen species produced as a normal part of metabolism.The hyperfunction theory is a much newer theory which explains that ageing is as a result of the unnecessary and unwanted continuation of certain metabolic processes at old age.In this review,we discuss the mechanisms which underlie the development of age-related cancer.We also discuss the aforementioned theories of ageing.We conclude by explaining the opposing views of proponents of both theories and provide a new viewpoint by revealing a point of synergy in the two theories.
