Representative tumour biopsy (patient 12). (a) Macroscopic view of ex vivo liver tissue with tumour infiltration, including viable (V) and necrotic (N) areas. (b) Strong and homogenous GPA33 expression in viable tumour, demonstrated by IHC. (c) Autoradiograph of corresponding tissue in (a) showing high uptake of 131I-huA33 in viable areas and similar degree of uptake by viable cell clusters of tumour within morphologically necrotic areas of the tumour (arrows). (d) IHC section showing CD-31 positive vessels predominantly in viable areas of tumour.