Our failure to identify PTEN mutations and/or PTEN DNA copy-number loss in some tumors with PTEN deficiency by IHC might be due to epigenetic mechanisms of PTEN silencing, incomplete sequencing coverage of the PTEN gene (exon 1 and the 5′ untranslated region [UTR] not sequenced) or the insensitivity of these methods when using heterogeneous tumor samples (the definition of PTEN deficiency used for the IHC test was >20% of tumor cells) [37]. This evidence concerns the gene PTEN and neoplasm.