USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

Which tumor is characterized by amplification of N-MYC oncogene and increased HVA and VMA in urine?

1. Neuroblastoma

2. Primary B-cell lymphoma

3. Hypomagnesemia

4. Primary hyperparathyroidism

The correct answer is: Neuroblastoma

Neuroblastoma is a tumor that primarily arises from neuroblasts, which are immature nerve cells. It is most commonly found in children and is associated with certain characteristic features, including the amplification of the N-MYC oncogene. This amplification plays a significant role in the aggressiveness and prognosis of the tumor. In addition to the genetic aspect, neuroblastoma often leads to increased levels of catecholamine metabolites in the urine, specifically homovanillic acid (HVA) and vanillylmandelic acid (VMA). These metabolites are the breakdown products of catecholamines such as norepinephrine and epinephrine, which are synthesized by neuroblastoma cells. Therefore, the detection of elevated HVA and VMA in a patient's urine is a key diagnostic marker for neuroblastoma, helping differentiate it from other conditions. Other options related to this question do not align with the specific characteristics of neuroblastoma. Primary B-cell lymphoma does not involve N-MYC amplification or increased HVA and VMA production. Hypomagnesemia and primary hyperparathyroidism are not tumors and thus do not relate to the question at all. This specificity further underscores neuroblastoma's distinct profile, linking its genetic and biochemical features directly to