Loss of PTEN expression in MCL. (A) Core from a PTEN-null adenocarcinoma control showing PTEN-negative tumor islands surrounded by PTEN-positive stroma by IHC (original magnifications ×50 and ×200). (B) Representative images of MCL cores with and without loss of PTEN expression (original magnifications ×50 and ×200). Macrophages and blood vessels were used as internal controls. (C) Pie chart showing the proportion of all biopsies with PTEN loss and blastoid morphology accompanied by a bar graph of distribution of PTEN loss in blastoid and nonblastoid MCL. (D) Dot plot comparing p110β expression levels between cores with and without loss of PTEN expression showing no difference among the 3 groups (PTEN−, PTEN 1+, and PTEN2+). There was also no significant difference in expression of p110α and δ between these groups (data not shown). (E) Western blot for PTEN expression in 12 MCL cell suspensions showing loss of expression in 2 samples (indicated by arrows). (F) Results of ATP cytotoxicity assay after 72 hours’ treatment showing no benefit from addition of a p110β-selective inhibitor to GS-1101 in 2 MCL suspensions exhibiting loss of PTEN expression.