 This is a 4-cohort single period study. The four cohorts will consist of healthy volunteers, and subjects with mild, moderate, and severely impaired hepatic function. Each cohort will receive the same treatment consisting of a single oral 75mg dose of palbociclib administered with food. Serial PK samples will be drawn up to 120 hours post dose for the cohort consisting of healthy volunteers, and will continue until up to 192 hours post-dose for the cohorts of hepatic impairment subjects. 