Fig. 1

Cellular location of Stat proteins in melanoma precursor lesions before and after systemic IFN- α treatment.

Following immunohistochemistry with polyclonal antibodies to Stat1, 2, and 3, the stained nevus sections were subjected to spectral imaging. (A) Section of a nevus obtained before IFN-α treatment, probed with a Stat3-specific antibody. (B) Section of a nevus excised after treatment, stained with the same Stat3 antibody. (C) Section of an atypical nevus resected after treatment, probed with an antibody to Stat1. (D) Section of a nevus removed after treatment, stained with a Stat2-specific antibody. The tissue sections presented in (A) and (B) were prepared from nevi of the same patient as were those shown in (C) and (D). Depicted on the left of each panel is a Red-Green-Blue (RGB) image of the nevus section, and on the right, a corresponding spectrally segmented image. In each of the spectral images, the assigned pseudocolor, red, represents Stat protein located in the cytoplasm; blue, the hematoxylin (nuclear) counterstain; and yellow, Stat protein residing in the nucleus.