Fig. 3
From: Systemic Interferon-α (IFN-α) Treatment Leads to Stat3 Inactivation in Melanoma Precursor Lesions
Stat3 protein, constitutively phosphorylated in atypical nevi and adjacent normal skin, is dephosphorylated following systemic IFN- α treatment.
Sections of atypical nevi obtained from a patient before (A) and after treatment (B) were stained with a Stat3 antibody that recognized Stat3 protein only when phosphorylated at Tyr705. Depicted on the left is the RGB image of the nevus section, and on the right, the corresponding spectrally segregated image. In the spectral image, the assigned pseudocolor, red, represents Stat protein located in the cytoplasm; blue, the hematoxylin (nuclear) counterstain; and yellow, Stat protein residing in the nucleus. (C) Total cell lysates (20 µg/sample), prepared from snap-frozen sections of an atypical nevus (a and b) and normal skin surrounding the nevus (c and d), obtained from a same patient before (a and c) and after treatment (b and d), were analyzed by immunoblotting with the phospho-Stat3 (Tyr705) antibody.