Review Question - QID 211045

A 56-year old man presents to his primary care physician complaining of a dark spot on his left thigh. He says that he first noticed the spot about 3 years ago when he went to the beach with his family; however, at the time it was very small and he didn't think that it was worth mentioning. Since then, it has been growing slowly and he is now concerned about its size. He says that he does not have any other symptoms associated with the lesion. Physical exam reveals an asymmetric 2.5 centimeter plaque with irregular borders and a varying pattern of brown coloration. The lesion is studied and found to have a mutation in a gene that inhibits cyclin function. Which of the following is most likely true of this gene?