Both STAT1 and STAT4 are important factors for Th1 cells polarization,590 STAT1 enhancing cell division.591 STAT6 modulates IL4 and IL13 via Th2 signaling and may inhibit Th1 polarization.590,592 STAT4 can also activate NK cells while STAT5 can promote white blood cells formation, and STAT6 promote B cell proliferation and survival.591 STAT3 is excessively activated in AML, multiple myeloma, and various solid tumors like breast, colon, liver, head and neck, lung, and ovarian cancers, correlating with unfavorable clinical outcomes.593–598. Here, STAT4 is linked to AL amyloidosis.