How are genes that increase cancer risk commonly transmitted?

How are genes that increase cancer risk commonly transmitted?

• A. Horizontally, through siblings
• B. Autosomal recessively
• C. Autosomal dominantly
• D. Via environmental exposure

Answer: (C)

Genes that increase cancer risk are most commonly transmitted in an autosomal dominant manner. This means that only one copy of the mutated gene, inherited from either parent, is sufficient to increase an individual's risk of developing cancer. In the context of cancer predisposition, certain genetic mutations (such as those in the BRCA1 and BRCA2 genes) exemplify this pattern of inheritance. An individual carrying a mutation in one of these genes has a significantly higher lifetime risk of breast cancer, even if the other copy is normal. The autosomal dominant transmission explains why cancer risk can appear in multiple generations of a family, as the mutated gene can be passed from an affected parent to their offspring, regardless of the sex of the children. Understanding the mode of inheritance is crucial for genetic counseling and for assessing the risk in family members of individuals with a hereditary cancer syndrome. In contrast, genes that would be transmitted autosomal recessively would require both copies to be mutated for an increased risk of cancer to occur, which is less common in terms of familial cancer syndromes. Environmental exposure can influence cancer risk but does not involve genetic transmission.

Genes that increase cancer risk are most commonly transmitted in an autosomal dominant manner. This means that only one copy of the mutated gene, inherited from either parent, is sufficient to increase an individual's risk of developing cancer.

In the context of cancer predisposition, certain genetic mutations (such as those in the BRCA1 and BRCA2 genes) exemplify this pattern of inheritance. An individual carrying a mutation in one of these genes has a significantly higher lifetime risk of breast cancer, even if the other copy is normal. The autosomal dominant transmission explains why cancer risk can appear in multiple generations of a family, as the mutated gene can be passed from an affected parent to their offspring, regardless of the sex of the children.

Understanding the mode of inheritance is crucial for genetic counseling and for assessing the risk in family members of individuals with a hereditary cancer syndrome. In contrast, genes that would be transmitted autosomal recessively would require both copies to be mutated for an increased risk of cancer to occur, which is less common in terms of familial cancer syndromes. Environmental exposure can influence cancer risk but does not involve genetic transmission.