Figure 2.

Localization of activated Stat3 to tumor cells using an in situ hSIE binding assay. (A) At low power (50× magnification), a large number of positive cells are seen localized to tumor cells (red arrows). (B) When observed under high power (100× magnification), the positive cells are closely associated with the periphery of the tumor parenchyma (yellow arrows) and often penetrate into the parenchyma itself (red arrows). (C) Tumor sections labeled with a ³⁵S-labeled oligonucleotide probe specific to NF-κB show no positive cells, indicating that the ³⁵S-hSIE labeling is specific. (D) Normal mucosa from a control without cancer labeled with hSIE probe shows a limited number of positive cells (red arrows).