What is one potential outcome of a mutation in one of the two copies of ras?

The possible outcome is having cancer sooner than expected, for example, a thyroid cancer.

RAS is a group of proteins that when the gene that codes them gets mutated, the proteins become a cause of cancer.
This can be explained by the two hit theory. In this theory, cancer is the result of the accumulation of mutations that occurs in the DNA of a certain cell.
If one mutation happens, that cell won't become a carcinogenic cell, unless the other copy also mutates. With both copies affected, the cell is carcinogenic and will become way more active, multiplying a lot, which leads to more cells affected.