Based on what you read in this chapter, Can a tumor arise from a single mutated cell? Are all the cells in a tumor identical?

Key Concepts

Mutation and Tumorigenesis

Tumorigenesis begins with mutations in the DNA of a single cell, which can lead to uncontrolled cell division. These mutations may affect genes that regulate cell growth and division, such as oncogenes and tumor suppressor genes. A single mutated cell can proliferate, giving rise to a tumor, illustrating the importance of genetic changes in cancer development.

Clonal Expansion

Once a cell undergoes a mutation that promotes its growth, it can replicate, leading to clonal expansion. This means that all descendant cells from the original mutated cell will share the same genetic mutation, making them genetically identical. However, as the tumor grows, additional mutations can occur, leading to genetic diversity within the tumor.

Tumor Heterogeneity

Tumor heterogeneity refers to the presence of different genetic and phenotypic variations within a tumor. While a tumor may originate from a single mutated cell, subsequent mutations and environmental factors can create a diverse population of cells. This heterogeneity can complicate treatment, as different cells may respond differently to therapies.