Down’s syndrome predisposes to _____cancer –
## Core Concept
Down's syndrome, also known as Trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. Individuals with Down's syndrome are at an increased risk of developing certain medical conditions, including cancers. The underlying reason for this predisposition is related to the extra genetic material, which can lead to overexpression of genes involved in cell growth and division.
## Why the Correct Answer is Right
The correct answer, **C. Acute Lymphoblastic Leukemia (ALL)**, is right because individuals with Down's syndrome have a higher risk of developing ALL, particularly the megakaryoblastic subtype (AMKL). This is due to the presence of extra copies of genes on chromosome 21 that may contribute to leukemogenesis. The risk of ALL in children with Down's syndrome is significantly higher than in the general population, and it accounts for a substantial proportion of the increased cancer risk observed in these individuals.
## Why Each Wrong Option is Incorrect
- **Option A:** While there is an increased risk of various cancers in Down's syndrome, **Breast Cancer** is not specifically highlighted as a major risk. Breast cancer risk in the general population is influenced by a variety of genetic and hormonal factors, and there isn't a direct, significant link established specifically with Down's syndrome.
- **Option B:** **Brain Tumors** can occur in individuals with Down's syndrome, but they are not the most commonly associated cancer type with this condition. The increased risk is more notably associated with hematological malignancies.
- **Option D:** **Carcinoma of the Lung** is not specifically mentioned as a cancer type with increased incidence in Down's syndrome. Smoking and environmental exposures are major risk factors for lung cancer in the general population.
## Clinical Pearl / High-Yield Fact
A key point to remember is that individuals with Down's syndrome have an increased risk of **Acute Lymphoblastic Leukemia (ALL)** and **Acute Myeloid Leukemia (AML)**, particularly the megakaryoblastic subtype. Early recognition and monitoring for these conditions are crucial in the management of patients with Down's syndrome.
## Correct Answer: C. Acute Lymphoblastic Leukemia (ALL).