Final answer:
If a cancer is associated with the deletion of a particular part of a chromosome, the region likely contains a tumor-suppressor gene, whose loss can result in uncontrolled cell division and cancer. Tumor-suppressor genes act as brakes to stop cell proliferation while oncogenes act as accelerators when mutated or overexpressed.
Step-by-step explanation:
When cancers are associated with the deletion of parts of a chromosome, the deleted region typically contains a tumor-suppressor gene. Tumor-suppressor genes are crucial for inhibiting cell division, survival, or other properties of cancer cells and are often disabled by genetic changes that promote cancer. On the other hand, oncogenes are genes that, when mutated or overexpressed, can push cells to divide and proliferate undesirably. In the context of cancer, these gene mutations disrupt the homeostatic balance of cell division, leading to uncontrolled cell proliferation and tumor growth.
While oncogenes can be thought of as the cell's 'accelerator,' encouraging cell division, tumor-suppressor genes act as the 'brake pedal,' halting inappropriate cell division. A deletion in a chromosome that causes cancer would thus likely result from the loss of these vital 'brake pedal' genes. In contrast, amplification or overexpression of oncogenes can lead to the formation of oncoproteins that stimulate excessive cell division. Large scale mutations like deletions, gains, and chromosomal translocations can cause either the inappropriate activation of oncogenes or the inactivation of tumor-suppressor genes, with both scenarios potentially leading to cancer.