Final answer:
Chromosomal changes include deletions, duplications, inversions, and translocations. Cancer is not usually inherited because it is caused by somatic mutations, which are acquired and not passed through gametes. Inherited genetic mutations can increase cancer risk but are not the direct cause of most cancers.
Step-by-step explanation:
The main types of chromosomal changes include chromosomal structural rearrangements such as deletions, duplications, inversions, insertions, and translocations. Cancer generally occurs due to somatic mutations, which are not hereditary, as they occur in body cells other than gametes and cannot be passed on to offspring. In contrast, germline mutations that occur in gametes can be inherited. Most cancers arise from an accumulation of somatic mutations that lead to the deregulation of the cell cycle, hence why cancer is usually not inherited.
Types of Chromosomal Alterations
Deletion - a part of the chromosome is lost.
Duplication - sections of a chromosome are duplicated.
Inversion - a chromosome segment is reversed end to end.
Translocation - a segment of one chromosome is transferred to another chromosome.
Why Cancer Is Not Usually Inherited
Cancer often results from genetic damage to proto-oncogenes and tumor-suppressor genes that regulate cell division. These changes are usually acquired during a person's life rather than being inherited from a parent. While certain inherited genetic mutations can increase the risk of cancer, the majority of cancers are not directly passed down through families.