Data Loss Prevention comes with a set of predefined expressions. These expressions cannot be modified or deleted.
Data Loss Prevention verifies these expressions using pattern matching and mathematical equations. After Data Loss Prevention matches potentially sensitive data with an expression, the data may also undergo additional verification checks.
For a complete list of predefined expressions, see the Data Protection Lists document at http://docs.trendmicro.com/en-us/enterprise/data-protection-reference-documents.aspx.