Arrange the incidence of various types of breast cancers in increasing incidence. a. PTEN ( Cowden disease )b. Sporadic breast cancerc. Hereditary breast cancerd. BRCA1e. BRCA2f. Familial breast cancer
## Core Concept
The question tests the understanding of the incidence rates of different types of breast cancers, including sporadic, hereditary, familial, and those associated with specific genetic mutations like BRCA1, BRCA2, and PTEN (Cowden disease).
## Why the Correct Answer is Right
The correct order from lowest to highest incidence is based on the prevalence of each type in the general population.
- **PTEN (Cowden disease)**: This is a rare genetic disorder associated with an increased risk of breast cancer, but it has a very low incidence.
- **BRCA1 and BRCA2**: These genetic mutations significantly increase the risk of breast cancer but are relatively rare in the population.
- **Hereditary breast cancer**: This term often refers to breast cancer caused by specific inherited genetic mutations, which would include BRCA1 and BRCA2 but can also imply other less common genetic syndromes.
- **Familial breast cancer**: This refers to breast cancer that occurs in families but does not necessarily imply a known genetic mutation. It is more common than hereditary breast cancer due to the broader criteria.
- **Sporadic breast cancer**: This is the most common type, accounting for about 70-80% of all breast cancer cases, as it occurs without a clear family history or identifiable genetic mutation.
## Why Each Wrong Option is Incorrect
- **Option A:** This option does not correctly order the types of breast cancer by incidence.
- **Option B:** Similarly, this option misorders the types, not reflecting the actual incidence rates.
- **Option D:** This option also incorrectly arranges the types of breast cancer by incidence.
## Clinical Pearl / High-Yield Fact
A key point to remember is that **sporadic breast cancer** accounts for the majority of cases, while **genetic syndromes** like BRCA1, BRCA2, and PTEN (Cowden disease) contribute to a smaller but significant portion of breast cancer cases. Understanding the spectrum of breast cancer etiology is crucial for risk assessment and management.
## Correct Answer: C. a, d, e, f, b