PTEN and breast carcinoma: Furthermore, > 7% of breast cancer samples contained either deep depletions, truncating and in-frame mutations, missense mutations or mRNA downregulation in the PTEN, compared with 2.2% of samples containing mainly alterations in the mRNA levels (up- and downregulation), hardly amplification and deep deletions and no somatic mutations in the SYK gene (Figure 8C).