PTEN and hepatocellular carcinoma: Here, in the xenografts derived from PTEN-knockout hepatocellular carcinoma SMMC-7721 cells (SMMC-7721ΔPTEN) with re-expression of PTEN, PTENα, or PTENβ, we unexpectedly detected an additional band at ~ 68 kD under the expression of PTENα or PTENβ but not PTEN by Western blot analysis with an antibody against the C-terminus of PTEN (Fig. 1A).