AGR2 expression in human thyroid tissue samples. A) Representative images (at 200x magnification) of normal thyroid (NT) (inset 1), papillary thyroid carcinoma (PTC) (inset 2), normal colon sample (inset 4) (used as positive control) stained with a mouse monoclonal anti-AGR2 antibody. PTC shows a strong immunoreactivity for AGR2, whereas NT is negative. Inset 3, shows a PTC sample incubated only with secondary antibody as negative control. B) Expression of AGR2 in DNA array of 15 normal thyroid (NT) samples and 43 PTC. The box plot of AGR2 shows a significant up-regulation of this gene in tumor tissues. C) Quantitative RT-PCR showing increased levels of AGR2 in PTC samples (n = 10) in comparison to normal thyroid controls (n = 10). The level of AGR2 expression in each sample was measured by comparing its fluorescence threshold with the average fluorescence threshold of the NT samples.