One of the early studies in this area delineated how downregulation or absence of STIM1 and STIM2 in cytotoxic T lymphocytes (CTLs; a subset of anti-tumor immune cells) prevents the production of cytolytic factors (interferon-γ and TNF-α), thus releasing control on tumor cell engraftment and in vivo tumor growth [299]. Here, STIM1 is linked to neoplasm.