PIK3CA and Miyoshi myopathy: Compared with 12% of PTEN loss in CM where deletions and mutations both account for the changes (17, 79), PTEN is deeply deleted in merely 6.0% of MM cases and has hardly any mutations (16) Furthermore, there is rare co-occurrence of deleted PTEN and amplified KIT that possibly implies that loss of PTEN or gain of KIT are redundant for the activation of the PI3K pathway in MM.