C6orf120 is a secreted protein that promotes cell cycle progression of CD4(+) T-cells, not hepatocytes. In humans it has its main role in tunicamycin-induced CD4(+) T apoptosis that may be associated with endoplasmatic reticulum stress. This suggests that it might be a new cytokine with immununoregulatory function that is selective for CD4+ T cells. It is mainly expressed in hepatocytes and cells in germinal centre of lymph nodes [1].

1: Role of C6ORF120, an N-glycosylated protein, is implicated in apoptosis of CD4(+) T lymphocytes. Li X, Qiao Y, Chang LS, Xiao F, Lu LH, Hao XH, Zhang RW, Wu H, Wei HS; Chin Med J (Engl). 2011;124:3560-3567. PMID:22340178