Which statement regarding tumor markers in childhood cancers is true?

• A. AFP is a glycoprotein expressed by neuroblastoma cells
• B. N-myc oncogene is a DNA sequence expressed by neuroblastoma cells
• C. AFP is an RNA sequence expressed by fetal liver and yolk sac tissue
• D. N-myc oncogene is a DNA sequence expressed by fetal liver cells and yolk sac tissue

Answer: (B)

In neuroblastoma, a key tumor marker is amplification of the N-myc oncogene. This gene is a DNA sequence, and when copies are increased in tumor cells, it leads to overexpression of the N-myc protein, driving rapid tumor growth and signaling a poorer prognosis. That makes the statement describing the N-myc oncogene as a DNA sequence expressed by neuroblastoma cells the true one.

AFP, on the other hand, is a fetal glycoprotein produced by the liver and yolk sac, not by neuroblastoma cells, and it is not an RNA sequence. Elevated AFP is associated with hepatoblastoma and some germ cell tumors, not neuroblastoma. The idea that N-myc is expressed by fetal liver or yolk sac tissue, or that AFP is produced by neuroblastoma cells, mixes up tissue sources and the type of biomolecule, which is why those options aren’t correct.