Final answer:
Cell fusion experiments indicate that the cancer phenotype can be dominant due to the behavior of oncogenes with gain-of-function mutations. Understanding gene expression patterns in cancer cells can help in identifying treatment targets.
Step-by-step explanation:
The question pertains to the nature of cancerous cells when compared to normal cells, especially in the context of cell fusion experiments. Such experiments have shown that when a non-cancerous cell is fused with a cancerous cell, the resulting cell often exhibits the cancer phenotype. This observation supports the concept that the cancer phenotype can be dominant. This is because oncogenes, which are genes that have the potential to cause cancer, typically act in a dominant fashion through gain-of-function mutations. Such mutations lead to the production of proteins that are constitutively active, overriding the effects of the normal allele.
Additionally, understanding gene expression patterns in cancer cells can provide insights into the nature of the cancer and its potential treatment. Cancer cells, being clones, reveal patterns of gene expression that can help in identifying targets for therapy. Mutations that affect cell division, whether by promoting or suppressing it, can contribute to the development of cancer. Variations such as the ones observed in cells in culture, including the lack of contact inhibition in cancer cells, are key characteristics that differentiate them from normal cells.