What are the similarities between "Huckleberry Finn" and "The Piano Lesson"?

I just fail to see a connection other than that they both contain the issue of slavery.

Can someone please enlighten me?

The Piano Lesson : http://en.wikipedia.org/wiki/The_Piano_Lesson

http://www.sparknotes.com/drama/piano/

Huckleberry Finn : http://en.wikipedia.org/wiki/Adventures_of_Huckleberry_Finn

http://www.sparknotes.com/lit/huckfinn/