Filtered deformations of commutative algebras of Krull dimension two

Let $F$ be an algebraically closed field of positive characteristic and let $R$ be a finitely generated $F$-algebra with a filtration with the property that the associated graded ring of $R$ is an integral domain of Krull dimension two. We show that under these conditions $R$ satisfies a polynomial identity, answering a question of Etingof in the affirmative in a special case.
Comment: 9 pages