"Moldy" grains in some regions of China contain a substance that causes a specific G-to-T mutation in gene p53. The population in these regions is expected to be at an increased risk of which of the following diseases?

Question

"Moldy" grains in some regions of China contain a substance that causes a specific G-to-T mutation in gene p53.  The population in these regions is expected to be at an increased risk of which of the following diseases?

Quizplus · Accepted Answer

When the humidity and temperature are favorable, specific strains of the fungi Aspergillus flavus and Aspergillus parasiticus grow on foods such as corn, soybeans, and peanuts, producing aflatoxins as a byproduct. These aflatoxins are categorized as A1, B2, G1, and G2, with aflatoxin B1 the most common and most toxic. High levels of dietary aflatoxin intake have been strongly associated with hepatocellular carcinoma. In certain areas within Asia and Africa where aflatoxin B1 exposure is high, p53 mutations have been identified in most individuals who developed hepatocellular carcinoma. More than 90% of these aflatoxin-induced p53 mutations are a classic G:C → T:A transversion in codon 249. In addition, research suggests that the combination of chronic aflatoxin exposure and hepatitis B infection significantly increases the risk of developing hepatocellular carcinoma. (Choices A, B, C, E, F, G, and H) Lung cancer, infectious diarrhea, dilated cardiomyopathy, congenital heart defects, hypothyroidism, osteoporosis, and pancreatic cancer are not associated with aflatoxin-induced mutation of the p53 gene. Educational Objective: High levels of dietary aflatoxin exposure is associated with a G:C → T:A transversion in codon 249 of the p53 gene, a mutation thought to greatly increase the risk of developing hepatocellular carcinoma.

"Moldy" Grains in Some Regions of China Contain a Substance