Immunofluorescence staining shows activation of JAK2, JNK, SRC, and c-ABL signaling in SSc with increased staining for P-JAK2 (Tyr-1007/1008), P-JNK (Thr-183/ Tyr-185), P-SRC (Tyr-416), and P-c-ABL (Tyr-412) in fibroblasts of SSc skin as compared to skin from healthy individuals (Fig. 3a, b). Here, JAK2 is linked to systemic sclerosis.