What are the characteristics of malignant tumors? Select all that apply.

Rationale:

A. Sickle cell anemia is a monogenic disorder caused by a mutation in the HBB gene, which leads to abnormal hemoglobin S production. It follows a Mendelian autosomal recessive inheritance pattern, meaning a person must inherit two defective alleles (one from each parent) to express the disease. Environmental factors have little influence on whether the disease occurs, although they can affect disease severity.

B. Cystic fibrosis is caused by mutations in the CFTR gene and is also a single-gene autosomal recessive disorder. Disease expression is largely determined by genetics, although certain environmental factors, like respiratory infections, may influence symptoms and progression. It is not considered multifactorial because a single gene mutation is sufficient to cause the disorder.

C. Hemophilia A is an X-linked recessive disorder caused by a mutation in the factor VIII gene. Males are predominantly affected because they have only one X chromosome. This disorder follows a single-gene inheritance pattern, and while environmental factors can influence bleeding risk, the underlying cause is genetic alone.

D. Cleft palate is a classic example of a multifactorial disorder. It results from the interaction of multiple genes and environmental factors. Genetic predisposition may increase risk, but environmental influences—such as maternal smoking, alcohol use, certain medications, or nutritional deficiencies during pregnancy—can trigger or exacerbate the condition. Unlike single-gene disorders, multifactorial conditions do not follow simple Mendelian inheritance and often appear sporadically within families, though they may recur more frequently among relatives.

Rationale:

A. Decreased antibody production is primarily associated with cortisol, a glucocorticoid, not aldosterone. Aldosterone’s main role is electrolyte and fluid balance, not direct modulation of adaptive immunity.

B. Bronchodilation is mainly influenced by catecholamines (epinephrine and norepinephrine) during the stress response. Aldosterone does not directly cause bronchodilation.

C. Impaired wound healing is also largely due to glucocorticoids like cortisol, which suppress immune function and fibroblast activity. Aldosterone itself does not significantly impair tissue repair.

D. Aldosterone indirectly contributes to modulation of the inflammatory response. By increasing sodium and water retention and affecting vascular function, aldosterone can reduce tissue edema and inflammatory mediator accumulation. This effect is less pronounced than cortisol but still relevant during the stress response.

E. This is the primary and most significant effect of aldosterone. Aldosterone acts on the renal distal tubules and collecting ducts to increase sodium reabsorption and potassium excretion, which helps maintain blood volume and blood pressure during stress. This effect is critical for the body’s hemodynamic stability under stressful conditions.