Oncogenes, Proto-Oncogenes, and Lineage Restriction of Cancer Stem Cells

Abstract

In principle, an oncogene is a cellular gene (proto-oncogene) that is dysfunctional, due to mutation and fusion with another gene or overexpression. Generally, oncogenes are viewed as deregulating cell proliferation or suppressing apoptosis in driving cancer. The cancer stem cell theory states that most, if not all, cancers are a hierarchy of cells that arises from a transformed tissue-specific stem cell. These normal counterparts generate various cell types of a tissue, which adds a new dimension to how oncogenes might lead to the anarchic behavior of cancer cells. It is that stem cells, such as hematopoietic stem cells, replenish mature cell types to meet the demands of an organism. Some oncogenes appear to deregulate this homeostatic process by restricting leukemia stem cells to a single cell lineage. This review examines whether cancer is a legacy of stem cells that lose their inherent versatility, the extent that proto-oncogenes play a role in cell lineage determination, and the role that epigenetic events play in regulating cell fate and tumorigenesis.

An Update on the Effectiveness of Probiotics in the Prevention and Treatment of Cancer

“…Oncogene expression causes cells to exhibit the properties of tumour cells, whereas proto-oncogenes are the normal nonmutated forms of oncogenes [97]. Proto-oncogenes are the precursors of oncogenes and are converted into oncogenes upon mutation [98]. The downregulation of oncogenes is one of the druggable targets of cancer therapy [99].…”

Metabolomics and the Multi-Omics View of Cancer

“…Most cancer-associated or cancer driver genes fall into two broad categories: (1) tumor suppressor genes and (2) oncogenes or proto-oncogenes [1]. Tumor suppressor genes act to suppress cell proliferation and tumor development.…”

“…In other words, they are anti-oncogenes. If a tumor suppressor gene is mutated, damaged, or altered epigenetically, it can lead to cell proliferation and oncogenesis [1]. Tumor suppressors fall into six main categories: (a) cell cycle control genes or cell division inhibitors, (b) hormone or growth factor receptors, (c) checkpoint control genes, (d) apoptosis inducers, (e) cell ad-hesion genes, and (f) DNA repair genes.…”

“…In contrast to tumor suppressor genes (which act as carcinogenic brakes), oncogenes act as carcinogenic accelerators. More specifically, oncogenes are mutated genes that contribute to the development of a cancer [1]. Unmutated oncogenes are called proto-oncogenes.…”

“…It can grow quickly or emerge slowly, it can be benign or malignant, it can strike at any age, and it can appear in almost any cell, tissue, or organ. To date, more than 200 different types of cancers have been named or identified [1] and the list keeps growing. The many faces of cancer have made it a difficult disease to describe and an even more difficult disease to understand.…”