CISH and breast cancer: The suppressor of cytokine signaling (SOCS) family proteins has been implicated in the negative regulation of various cytokines.4 Recently, emerging evidence suggests that SOCS is a suppressor for several types of cancers, including colon and rectal cancer, lung cancer, prostate cancer, and breast cancer.5–8 The SOCS pathway is a key negative regulator of cytokine signaling that inhibits the JAK/STAT signal transduction pathway.9 SOCS3 is a major member of SOCS family.