Table I.

Proposed Ancillary Testing for Pancreatobiliary Strictures

Marker	Purpose	Diagnostic finding	Utility
Digital image analysis	Separation of benign from malignant strictures	Aneuploid and tetraploid results support malignancy	Does not improve diagnostic accuracy above that achievable by cytology alone
KRAS	Separation of benign from malignant strictures	Mutation present	Insufficient specificity for malignancy to warrant usage
Sequential mutational analysis	Separation of benign from malignant strictures	Loss of heterozygosity	Diagnostic utility to be determined by future studies
FISH	Separation of benign from malignant strictures	Presence of copy number abnormalities in CEP3, CEP7, CEP17, and abnormalities of 9p21 favor malignancy	Diagnostically useful. It is the preferred test to complement routine cytology