Final answer:
In summary, cancer development requires multiple genetic alterations, not just one or two, affecting various genes responsible for cell growth and division. This detailed process involves complex changes influencing the transformation of normal cells into malignant cancer cells.
Step-by-step explanation:
The statement that cancer usually requires only one or two genetic changes to the same cell lineage is false. The transformation of a normal cell into a cancer cell involves a multi-stage process characterized by accumulated genetic damage, affecting both proto-oncogenes and tumor-suppressor genes. This process often includes changes in multiple genes and can range from gain or loss of entire chromosomes to single-nucleotide mutations. The progression towards cancer entails the malfunction of genes that regulate cell growth and division, such as the conversion of proto-oncogenes to oncogenes and the disabling of tumor-suppressor genes.
Genetic alterations in cancer cells may result in the formation of cancer-causing oncogenes, over-expression of normal proto-oncogenes, or under-expression or disabling of tumor-suppressor genes. Additionally, each genetic alteration pushes the cell closer to acquiring the malignant phenotype that is characteristic of cancer cells, making a series of mutations typically necessary for cancer development.