Fig. 2

Hemizygous loss of SMAD4 was associated with lower SMAD4 protein expression. a Top: Images visualizing FISH analysis with DAPI stained nuclei (blue) and one respective two Texas red stained copies of the SMAD4 gene (red). Scale bar is equal to 2 μm. Bottom: Images visualizing biopsies from the TMA representing the expression intensities for scoring None, Low or High SMAD4 expression. b FISH analysis of a tissue microarray containing 846 tumors from 412 patients showed that hemizygous loss of SMAD4 (68.1%) occurred recurrently in SINETs. Biopsies on the TMA were both scored for SMAD4 gene copy number by FISH analysis and for SMAD4 protein expression by immunohistochemical staining. The distribution of SMAD4 protein expression by gene copy number [1,2,3] is shown. SMAD4 copy number was positively correlated with SMAD4 protein expression