All of the Following Environmental Factors Have Been Implicated in Cancer

Question

All of the following environmental factors have been implicated in cancer EXCEPT
A) viral infection.
B) exposure to X-rays.
C) exposure to polyvinyl chloride.
D) exposure to UV light.
E) exposure to PTC.

Accepted Answer

Exposure to PTC (phenylthiocarbamide) is not known to be a direct environmental factor in cancer development. The other options (viral infection, exposure to X-rays, exposure to polyvinyl chloride, and exposure to UV light) have all been shown to play a role in cancer development.